From 589778a521dba5e066b318bd1b312bfb674a0a62 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Mon, 19 Feb 2018 19:46:56 +0300
Subject: [PATCH 01/26] add comments on gql queries assert and compile
 functions

---
 graphql/tarantool_graphql.lua | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index 2805bc7..5e01ca3 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -414,6 +414,8 @@ local function parse_cfg(cfg)
     return state
 end
 
+--- The function checks if given query has an appropriate type
+--- (mutations are not supported yet)
 local function assert_gql_query_ast(func_name, ast)
     assert(#ast.definitions == 1,
         func_name .. ': expected an one query')
@@ -442,6 +444,8 @@ local function gql_execute(qstate, variables)
         operation_name)
 end
 
+--- The function parses a raw query string, validate the resulting query
+--- and return it ready for execution
 local function gql_compile(state, query)
     assert(type(state) == 'table' and type(query) == 'string',
         'use :validate(...) instead of .validate(...)')

From 417c83e70c783e156196a55a3c73cadfe7844497 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Tue, 20 Feb 2018 16:32:02 +0300
Subject: [PATCH 02/26] do small refactor; add comments

---
 graphql/tarantool_graphql.lua | 71 +++++++++++++++++++++++++++--------
 1 file changed, 55 insertions(+), 16 deletions(-)

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index 5e01ca3..3bf7ee4 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -30,6 +30,14 @@ local function avro_type(avro_schema)
             return 'record*'
         elseif utils.is_array(avro_schema) then
             return 'union'
+        elseif avro_schema.type == 'array' then
+            return 'array'
+        elseif avro_schema.type == 'array*' then
+            return 'array*'
+        elseif avro_schema.type == 'map' then
+            return 'map'
+        elseif avro_schema.type == 'map*' then
+            return 'map*'
         end
     elseif type(avro_schema) == 'string' then
         if avro_schema == 'int' then
@@ -105,6 +113,8 @@ end
 
 --- Non-recursive version of the @{gql_type} function that returns
 --- InputObject instead of Object.
+--- An error will be raised in case of fields that are not scalar types
+--- as there are no sense in non scalar arguments
 local function gql_argument_type(state, avro_schema)
     assert(type(state) == 'table',
         'state must be a table, got ' .. type(state))
@@ -115,17 +125,23 @@ local function gql_argument_type(state, avro_schema)
         assert(type(avro_schema.name) == 'string',
             ('avro_schema.name must be a string, got %s (avro_schema %s)')
             :format(type(avro_schema.name), json.encode(avro_schema)))
+
         assert(type(avro_schema.fields) == 'table',
             ('avro_schema.fields must be a table, got %s (avro_schema %s)')
             :format(type(avro_schema.fields), json.encode(avro_schema)))
 
+        ---@tfixme iteration over null table
+        --- maybe avro.scheme was meant?
         local fields = {}
-        for _, field in ipairs(fields) do
+        for _, field in ipairs(avro_schema.fields) do
+
             assert(type(field.name) == 'string',
                 ('field.name must be a string, got %s (schema %s)')
                 :format(type(field.name), json.encode(field)))
+
             local gql_field_type = convert_scalar_type(
                 field.type, {raise = true})
+
             fields[field.name] = {
                 name = field.name,
                 kind = types.nonNull(gql_field_type),
@@ -140,6 +156,8 @@ local function gql_argument_type(state, avro_schema)
         }))
 
         return res
+    --- elseif avro_type(avro_schema) == 'array' then
+
     else
         local res = convert_scalar_type(avro_schema, {raise = false})
         if res == nil then
@@ -149,20 +167,25 @@ local function gql_argument_type(state, avro_schema)
     end
 end
 
+
+--- Returns table of record's arguments
+--- all arguments are nullable
 local function convert_record_fields_to_args(state, fields)
     local args = {}
     for _, field in ipairs(fields) do
+
         assert(type(field.name) == 'string',
             ('field.name must be a string, got %s (schema %s)')
             :format(type(field.name), json.encode(field)))
+
         local gql_class = gql_argument_type(state, field.type)
         args[field.name] = nullable(gql_class)
     end
     return args
 end
 
---- Convert each field of an avro-schema to a graphql type and corresponding
---- argument for an upper graphql type.
+--- Recursively convert each field of an avro-schema to a graphql type and
+--- corresponding argument for an upper graphql type.
 ---
 --- @tparam table state for read state.accessor and previously filled
 --- state.types
@@ -170,10 +193,12 @@ end
 local function convert_record_fields(state, fields)
     local res = {}
     local object_args = {}
+
     for _, field in ipairs(fields) do
         assert(type(field.name) == 'string',
             ('field.name must be a string, got %s (schema %s)')
             :format(type(field.name), json.encode(field)))
+
         res[field.name] = {
             name = field.name,
             kind = gql_type(state, field.type),
@@ -186,7 +211,7 @@ end
 --- The function recursively converts passed avro-schema to a graphql type.
 ---
 --- @tparam table state for read state.accessor and previously filled
---- state.types
+--- state.types (state.types are gql types)
 --- @tparam table avro_schema input avro-schema
 --- @tparam[opt] table collection table with schema_name, connections fields
 --- described a collection (e.g. tarantool's spaces)
@@ -230,6 +255,7 @@ gql_type = function(state, avro_schema, collection, collection_name)
 
         local fields, _ = convert_record_fields(state, avro_schema.fields)
 
+        -- if collection param is passed
         for _, c in ipairs((collection or {}).connections or {}) do
             assert(type(c.type) == 'string',
                 'connection.type must be a string, got ' .. type(c.type))
@@ -333,9 +359,12 @@ gql_type = function(state, avro_schema, collection, collection_name)
             error('unrecognized avro-schema type: ' .. json.encode(avro_schema))
         end
         return res
+
     end
+
 end
 
+
 local function parse_cfg(cfg)
     local state = {}
     state.types = utils.gen_booking_table({})
@@ -356,10 +385,11 @@ local function parse_cfg(cfg)
 
     local fields = {}
 
-    for name, collection in pairs(state.collections) do
-        collection.name = name
+    for collection_name, collection in pairs(state.collections) do
+        collection.name = collection_name
         assert(collection.schema_name ~= nil,
             'collection.schema_name must not be nil')
+
         local schema = cfg.schemas[collection.schema_name]
         assert(schema ~= nil, ('cfg.schemas[%s] must not be nil'):format(
             tostring(collection.schema_name)))
@@ -367,21 +397,25 @@ local function parse_cfg(cfg)
             ('top-level schema name does not match the name in ' ..
             'the schema itself: "%s" vs "%s"'):format(collection.schema_name,
             schema.name))
-        state.types[name] = gql_type(state, schema, collection, name)
 
+        -- recursively converts all avro types into gql types in the given schema
+        state.types[collection_name] = gql_type(state, schema, collection, collection_name)
+
+        -- prepare arguments
         local _, object_args = convert_record_fields(state,
             schema.fields)
         local list_args = convert_record_fields_to_args(
-            state, accessor:list_args(name))
+            state, accessor:list_args(collection_name))
         local args = utils.merge_tables(object_args, list_args)
-        state.object_arguments[name] = object_args
-        state.list_arguments[name] = list_args
-        state.all_arguments[name] = args
+
+        state.object_arguments[collection_name] = object_args
+        state.list_arguments[collection_name] = list_args
+        state.all_arguments[collection_name] = args
 
         -- create entry points from collection names
-        fields[name] = {
-            kind = types.nonNull(types.list(state.types[name])),
-            arguments = state.all_arguments[name],
+        fields[collection_name] = {
+            kind = types.nonNull(types.list(state.types[collection_name])),
+            arguments = state.all_arguments[collection_name],
             resolve = function(rootValue, args_instance, info)
                 local object_args_instance = {} -- passed to 'filter'
                 local list_args_instance = {} -- passed to 'args'
@@ -397,7 +431,7 @@ local function parse_cfg(cfg)
                     end
                 end
                 local from = nil
-                return accessor:select(rootValue, name, from,
+                return accessor:select(rootValue, collection_name, from,
                     object_args_instance, list_args_instance)
             end,
         }
@@ -414,7 +448,7 @@ local function parse_cfg(cfg)
     return state
 end
 
---- The function checks if given query has an appropriate type
+--- The function checks if given query has an appropriate type 'query'
 --- (mutations are not supported yet)
 local function assert_gql_query_ast(func_name, ast)
     assert(#ast.definitions == 1,
@@ -427,6 +461,7 @@ local function assert_gql_query_ast(func_name, ast)
         type(operation_name))
 end
 
+--- The function just makes some assertions and then call graphql-lua execute
 local function gql_execute(qstate, variables)
     assert(qstate.state)
     local state = qstate.state
@@ -446,6 +481,9 @@ end
 
 --- The function parses a raw query string, validate the resulting query
 --- and return it ready for execution
+--- @tparam table state current state of graphql-lib, including
+--- schemas, collections and accessor
+--- @tparam string query raw query string
 local function gql_compile(state, query)
     assert(type(state) == 'table' and type(query) == 'string',
         'use :validate(...) instead of .validate(...)')
@@ -462,6 +500,7 @@ local function gql_compile(state, query)
         ast = ast,
         operation_name = operation_name,
     }
+
     local gql_query = setmetatable(qstate, {
         __index = {
             execute = gql_execute,

From 24ec6c4bfe129087c5d0cb0699dfabb31c997f2a Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Wed, 21 Feb 2018 21:16:31 +0300
Subject: [PATCH 03/26] add support for array avro type (only with scalars);
 change args generation behavior - now args are NOT generated from arrays; do
 small refactor; add test for array avro type usage

---
 graphql/tarantool_graphql.lua | 95 ++++++++++++++++++++++++++++++-----
 1 file changed, 82 insertions(+), 13 deletions(-)

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index 3bf7ee4..be1e19c 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -22,6 +22,7 @@ local tarantool_graphql = {}
 -- forward declarations
 local gql_type
 
+--- Returns type of the top element in the avro schema
 local function avro_type(avro_schema)
     if type(avro_schema) == 'table' then
         if avro_schema.type == 'record' then
@@ -104,10 +105,18 @@ local function convert_scalar_type(avro_schema, opts)
     elseif avro_t == 'string*' then
         return types.string
     end
+
+    if opts.is_items_type then
+        error('avro array items must have know scalar type, not: ' ..
+                json.encode(avro_schema))
+    end
+
     if raise then
         error('unrecognized avro-schema scalar type: ' ..
-            json.encode(avro_schema))
+        json.encode(avro_schema))
     end
+
+
     return nil
 end
 
@@ -130,8 +139,6 @@ local function gql_argument_type(state, avro_schema)
             ('avro_schema.fields must be a table, got %s (avro_schema %s)')
             :format(type(avro_schema.fields), json.encode(avro_schema)))
 
-        ---@tfixme iteration over null table
-        --- maybe avro.scheme was meant?
         local fields = {}
         for _, field in ipairs(avro_schema.fields) do
 
@@ -170,8 +177,15 @@ end
 
 --- Returns table of record's arguments
 --- all arguments are nullable
-local function convert_record_fields_to_args(state, fields)
+---
+--- @tparam table state
+--- @tparam table fields
+--- @tparam table opts include is_for_args flag to specify
+--- case when the function is used to collect arguments
+local function convert_record_fields_to_args(state, fields, opts)
     local args = {}
+    local is_for_args = opts and opts.is_for_args or false
+
     for _, field in ipairs(fields) do
 
         assert(type(field.name) == 'string',
@@ -179,7 +193,15 @@ local function convert_record_fields_to_args(state, fields)
             :format(type(field.name), json.encode(field)))
 
         local gql_class = gql_argument_type(state, field.type)
-        args[field.name] = nullable(gql_class)
+
+        -- arrays (gql lists) and maps can't be arguments
+        -- so these kinds are to be skipped
+
+        ---@todo consider case when gql_class is wrapper nonNull around List
+        --- or Map
+        if not(is_for_args and (gql_class == 'List' or gql_class == 'Map')) then
+            args[field.name] = nullable(gql_class)
+        end
     end
     return args
 end
@@ -190,9 +212,12 @@ end
 --- @tparam table state for read state.accessor and previously filled
 --- state.types
 --- @tparam table fields fields part from an avro-schema
-local function convert_record_fields(state, fields)
+--- @tparam table opts include is_for_args flag to specify
+--- case when the function is used to collect arguments
+local function convert_record_fields(state, fields, opts)
     local res = {}
     local object_args = {}
+    local is_for_args = opts and opts.is_for_args or false
 
     for _, field in ipairs(fields) do
         assert(type(field.name) == 'string',
@@ -203,12 +228,22 @@ local function convert_record_fields(state, fields)
             name = field.name,
             kind = gql_type(state, field.type),
         }
-        object_args[field.name] = nullable(res[field.name].kind)
+
+
+        -- arrays (gql lists) and maps can't be arguments
+        -- so these kinds are to be skipped
+
+        ---@todo consider case when gql_class is wrapper nonNull around List
+        --- or Map
+        if not (is_for_args and (res[field.name].kind == 'List'
+                            or res[field.name].kind == 'Map')) then
+            object_args[field.name] = nullable(res[field.name].kind)
+        end
     end
     return res, object_args
 end
 
---- The function recursively converts passed avro-schema to a graphql type.
+--- The function recursively converts passed avro-schema to a graphql type (kind)
 ---
 --- @tparam table state for read state.accessor and previously filled
 --- state.types (state.types are gql types)
@@ -237,12 +272,14 @@ gql_type = function(state, avro_schema, collection, collection_name)
         ('collection and collection_name must be nils or ' ..
         'non-nils simultaneously, got: %s and %s'):format(type(collection),
         type(collection_name)))
+
     local accessor = state.accessor
     assert(accessor ~= nil, 'state.accessor must not be nil')
     assert(accessor.select ~= nil, 'state.accessor.select must not be nil')
     assert(accessor.list_args ~= nil,
         'state.accessor.list_args must not be nil')
 
+    -- type of the top element in the avro schema
     local avro_t = avro_type(avro_schema)
 
     if avro_t == 'record' or avro_t == 'record*' then
@@ -255,7 +292,7 @@ gql_type = function(state, avro_schema, collection, collection_name)
 
         local fields, _ = convert_record_fields(state, avro_schema.fields)
 
-        -- if collection param is passed
+        -- if collection param is passed then go over all connections
         for _, c in ipairs((collection or {}).connections or {}) do
             assert(type(c.type) == 'string',
                 'connection.type must be a string, got ' .. type(c.type))
@@ -269,6 +306,7 @@ gql_type = function(state, avro_schema, collection, collection_name)
             assert(type(c.parts) == 'table',
                 'connection.parts must be a string, got ' .. type(c.parts))
 
+            -- gql type of connection field
             local destination_type =
                 state.types[c.destination_collection]
             assert(destination_type ~= nil,
@@ -287,6 +325,7 @@ gql_type = function(state, avro_schema, collection, collection_name)
 
             local c_list_args = state.list_arguments[c.destination_collection]
 
+            -- change fields that are represented by connections
             fields[c.name] = {
                 name = c.name,
                 kind = destination_type,
@@ -294,13 +333,16 @@ gql_type = function(state, avro_schema, collection, collection_name)
                 resolve = function(parent, args_instance, info)
                     local destination_args_names = {}
                     local destination_args_values = {}
+
                     for _, part in ipairs(c.parts) do
+
                         assert(type(part.source_field) == 'string',
                             'part.source_field must be a string, got ' ..
                             type(part.destination_field))
                         assert(type(part.destination_field) == 'string',
                             'part.destination_field must be a string, got ' ..
                             type(part.destination_field))
+
                         destination_args_names[#destination_args_names + 1] =
                             part.destination_field
                         destination_args_values[#destination_args_values + 1] =
@@ -344,6 +386,7 @@ gql_type = function(state, avro_schema, collection, collection_name)
             }
         end
 
+        -- create gql schema
         local res = types.object({
             name = collection ~= nil and collection.name or avro_schema.name,
             description = 'generated from avro-schema for ' ..
@@ -351,8 +394,30 @@ gql_type = function(state, avro_schema, collection, collection_name)
             fields = fields,
         })
         return avro_t == 'enum' and types.nonNull(res) or res
+
     elseif avro_t == 'enum' then
         error('enums not implemented yet') -- XXX
+
+    elseif avro_t == 'array' or avro_t == 'array*' then
+
+        assert(avro_schema.items ~= nil,
+            'items field must not be nil in array avro schema')
+        assert(type(avro_schema.items) == 'string',
+            'avro_schema.items must be a string, got ' .. type(avro_schema.item))
+
+        local gql_items_type = convert_scalar_type(avro_schema.items,
+            {is_items_type=true, raise=true})
+
+        local gql_array = types.list(gql_items_type)
+
+        if  avro_t == 'array*' then
+            return gql_array
+        end
+
+        if avro_t == 'array' then
+            return types.nonNull(gql_array)
+        end
+
     else
         local res = convert_scalar_type(avro_schema, {raise = false})
         if res == nil then
@@ -399,15 +464,19 @@ local function parse_cfg(cfg)
             schema.name))
 
         -- recursively converts all avro types into gql types in the given schema
+        assert(schema.type == 'record',
+            'top-level schema must have record avro type, not' .. schema.type)
         state.types[collection_name] = gql_type(state, schema, collection, collection_name)
 
-        -- prepare arguments
+        -- prepare arguments (their kinds)
         local _, object_args = convert_record_fields(state,
-            schema.fields)
+            schema.fields, {is_for_args=true})
         local list_args = convert_record_fields_to_args(
-            state, accessor:list_args(collection_name))
+            state, accessor:list_args(collection_name), {is_for_args=true})
         local args = utils.merge_tables(object_args, list_args)
 
+        -- list and map (avro array and map) can't be arguments
+
         state.object_arguments[collection_name] = object_args
         state.list_arguments[collection_name] = list_args
         state.all_arguments[collection_name] = args
@@ -580,4 +649,4 @@ function tarantool_graphql.new(cfg)
     })
 end
 
-return tarantool_graphql
+return tarantool_graphql
\ No newline at end of file

From 9a43096ee2e503aa10a8e66374084546fbd6d0b3 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Thu, 22 Feb 2018 14:45:40 +0300
Subject: [PATCH 04/26] simplify conditional statements

---
 graphql/tarantool_graphql.lua | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index be1e19c..4fbb0fe 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -199,7 +199,7 @@ local function convert_record_fields_to_args(state, fields, opts)
 
         ---@todo consider case when gql_class is wrapper nonNull around List
         --- or Map
-        if not(is_for_args and (gql_class == 'List' or gql_class == 'Map')) then
+        if (not is_for_args) or (gql_class ~= 'List' and gql_class ~= 'Map') then
             args[field.name] = nullable(gql_class)
         end
     end
@@ -235,8 +235,8 @@ local function convert_record_fields(state, fields, opts)
 
         ---@todo consider case when gql_class is wrapper nonNull around List
         --- or Map
-        if not (is_for_args and (res[field.name].kind == 'List'
-                            or res[field.name].kind == 'Map')) then
+        if (not is_for_args) or (res[field.name].kind ~= 'List'
+                            and res[field.name].kind ~= 'Map') then
             object_args[field.name] = nullable(res[field.name].kind)
         end
     end
@@ -257,6 +257,9 @@ end
 ---    automatically generate corresponding decucible fields.
 --- 2. The collection name will be used as the resulting graphql type name
 ---    instead of the avro-schema name.
+---
+--- Resulting object will look like this:
+---
 gql_type = function(state, avro_schema, collection, collection_name)
     assert(type(state) == 'table',
         'state must be a table, got ' .. type(state))
@@ -450,6 +453,7 @@ local function parse_cfg(cfg)
 
     local fields = {}
 
+    -- create fields (from collections) for top-level gql type 'query)
     for collection_name, collection in pairs(state.collections) do
         collection.name = collection_name
         assert(collection.schema_name ~= nil,

From 6bd1ca21f1aa3b56787166551e8b429de0dbdd2c Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Thu, 22 Feb 2018 15:22:56 +0300
Subject: [PATCH 05/26] add mised simple test for array support

---
 test/local/simple_array.result   |  7 +++
 test/local/simple_array.test.lua | 95 ++++++++++++++++++++++++++++++++
 2 files changed, 102 insertions(+)
 create mode 100644 test/local/simple_array.result
 create mode 100644 test/local/simple_array.test.lua

diff --git a/test/local/simple_array.result b/test/local/simple_array.result
new file mode 100644
index 0000000..a3f6c68
--- /dev/null
+++ b/test/local/simple_array.result
@@ -0,0 +1,7 @@
+RESULT
+---
+user_collection:
+- user_id: def
+  favs:
+    - potato
+    - fruit
\ No newline at end of file
diff --git a/test/local/simple_array.test.lua b/test/local/simple_array.test.lua
new file mode 100644
index 0000000..8a1ee82
--- /dev/null
+++ b/test/local/simple_array.test.lua
@@ -0,0 +1,95 @@
+#!/usr/bin/env tarantool
+
+local fio = require('fio')
+
+-- require in-repo version of graphql/ sources despite current working directory
+package.path = fio.abspath(debug.getinfo(1).source:match("@?(.*/)")
+                                :gsub('/./', '/'):gsub('/+$', '')) .. '/../../?.lua' .. ';' ..
+        package.path
+
+local json = require('json')
+local yaml = require('yaml')
+local graphql = require('graphql')
+local utils = require('graphql.utils')
+
+local schemas = json.decode([[{
+    "user": {
+        "name": "user",
+        "type": "record",
+        "fields": [
+            { "name": "id", "type": "string" },
+            { "name": "favs", "type": { "type": "array", "items": "string" } }
+        ]
+    }
+}]])
+
+local collections = json.decode([[{
+    "user_collection": {
+        "schema_name": "user"
+}]])
+
+local function access_function(parent, collection_name, filter, args)
+    --[[
+    print('DEBUG: collection_name: ' .. collection_name)
+    print('DEBUG: filter: ' .. json.encode(filter))
+    print('DEBUG: args: ' .. json.encode(args))
+    print('DEBUG: --------')
+    --]]
+    local obj
+    if collection_name == 'user_collection' then
+        obj = {
+            user_id = 'def',
+            favs = {'potato', 'fruit'}
+        }
+    else
+        error('NIY: ' .. collection_name)
+    end
+    if not utils.is_subtable(obj, filter) then
+        return {}
+    end
+    return { obj }
+end
+
+local accessor = setmetatable({}, {
+    __index = {
+        select = function(self, parent, collection_name, connection_name,
+                          filter, args)
+            return access_function(parent, collection_name, filter, args)
+        end,
+        list_args = function(self, connection_type)
+            if connection_type == '1:1' then
+                return {}
+            end
+            return {
+                { name = 'limit', type = 'int' },
+                { name = 'offset', type = 'long' },
+            -- {name = 'filter', type = ...},
+            }
+        end,
+    }
+})
+
+local gql_wrapper = graphql.new({
+-- class_name:class mapping
+    schemas = schemas,
+-- collection_{schema_name=..., connections=...} mapping
+    collections = collections,
+-- :select() and :list_args() provider
+    accessor = accessor,
+})
+
+local query_1 = [[
+    query obtainUserFavs($user_id: String) {
+        user_collection(user_id: $user_id, type: "type 1", size: 2) {
+            id
+            favs
+        }
+    }
+]]
+
+utils.show_trace(function()
+    local variables_1 = { user_id = 'def' }
+    local gql_query_1 = gql_wrapper:compile(query_1)
+    local result = gql_query_1:execute(variables_1)
+    print(('RESULT\n%s'):format(yaml.encode(result)))
+end)

From 31897d613082ce0f0b4678c551c091843f27701b Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Fri, 23 Feb 2018 20:05:22 +0300
Subject: [PATCH 06/26] add simple test for array avro type usage

---
 test/local/array_and_map.result   |  18 ++++
 test/local/array_and_map.test.lua | 131 ++++++++++++++++++++++++++++++
 2 files changed, 149 insertions(+)
 create mode 100644 test/local/array_and_map.result
 create mode 100755 test/local/array_and_map.test.lua

diff --git a/test/local/array_and_map.result b/test/local/array_and_map.result
new file mode 100644
index 0000000..f2614db
--- /dev/null
+++ b/test/local/array_and_map.result
@@ -0,0 +1,18 @@
+RESULT
+---
+user_collection:
+- user_id: def
+  favorite_food:
+  - meat
+  - potato
+...
+
+RESULT
+---
+organization_collection:
+- organization_id: def
+  organization_events:
+    holiday: nice holiday
+    new_year: hey hou
+...
+
diff --git a/test/local/array_and_map.test.lua b/test/local/array_and_map.test.lua
new file mode 100755
index 0000000..10b85e5
--- /dev/null
+++ b/test/local/array_and_map.test.lua
@@ -0,0 +1,131 @@
+#!/usr/bin/env tarantool
+
+local fio = require('fio')
+
+-- require in-repo version of graphql/ sources despite current working directory
+package.path = fio.abspath(debug.getinfo(1).source:match("@?(.*/)")
+                                :gsub('/./', '/'):gsub('/+$', '')) .. '/../../?.lua' .. ';' ..
+        package.path
+
+local json = require('json')
+local yaml = require('yaml')
+local graphql = require('graphql')
+local utils = require('graphql.utils')
+
+local schemas = json.decode([[{
+    "user": {
+        "name": "user",
+        "type": "record",
+        "fields": [
+            { "name": "user_id", "type": "string" },
+            { "name": "favorite_food", "type": {"type": "array", "items": "string"} }
+        ]
+    },
+    "organization": {
+        "name": "organization",
+        "type": "record",
+        "fields": [
+            { "name": "organization_id", "type": "string" },
+            { "name": "organization_events", "type": {"type": "map", "values": "string"} }
+        ]
+    }
+}]])
+
+local collections = json.decode([[{
+    "user_collection": {
+        "schema_name": "user"
+    },
+    "organization_collection": {
+        "schema_name": "organization"
+    }
+}]])
+
+local function access_function(parent, collection_name, filter, args)
+    --[[
+    print('DEBUG: collection_name: ' .. collection_name)
+    print('DEBUG: filter: ' .. json.encode(filter))
+    print('DEBUG: args: ' .. json.encode(args))
+    print('DEBUG: --------')
+    --]]
+    local obj
+    if collection_name == 'user_collection' then
+        obj = {
+            user_id = 'def',
+            favorite_food = { 'meat', 'potato' },
+        }
+    elseif collection_name == 'organization_collection' then
+        obj = {
+            organization_id = 'def',
+            organization_events = { holiday = 'nice holiday',
+                                    new_year = 'hey hou' },
+        }
+    else
+        error('NIY: ' .. collection_name)
+    end
+    if not utils.is_subtable(obj, filter) then
+        return {}
+    end
+    return { obj }
+end
+
+local accessor = setmetatable({}, {
+    __index = {
+        select = function(self, parent, collection_name, connection_name,
+                          filter, args)
+            return access_function(parent, collection_name, filter, args)
+        end,
+        list_args = function(self, connection_type)
+            if connection_type == '1:1' then
+                return {}
+            end
+            return {
+                { name = 'limit', type = 'int' },
+                { name = 'offset', type = 'long' },
+            -- {name = 'filter', type = ...},
+            }
+        end,
+    }
+})
+
+local gql_wrapper = graphql.new({
+-- class_name:class mapping
+    schemas = schemas,
+-- collection_{schema_name=..., connections=...} mapping
+    collections = collections,
+-- :select() and :list_args() provider
+    accessor = accessor,
+})
+
+local query_with_list = [[
+    query userFavs($user_id: String) {
+        user_collection(user_id: $user_id) {
+            user_id
+            favorite_food
+        }
+    }
+]]
+
+
+local query_with_map = [[
+    query obtainOrganizationEvents($organization_id: String) {
+        organization_collection(organization_id: $organization_id) {
+            organization_id,
+            organization_events
+        }
+    }
+]]
+
+
+utils.show_trace(function()
+    local variables_2 = { user_id = 'def' }
+    local gql_query_2 = gql_wrapper:compile(query_with_list)
+    local result = gql_query_2:execute(variables_2)
+    print(('RESULT\n%s'):format(yaml.encode(result)))
+end)
+
+utils.show_trace(function()
+    local variables_1 = {organization_id = 'def'}
+    local gql_query_1 = gql_wrapper:compile(query_with_map)
+    local result = gql_query_1:execute(variables_1)
+    print(('RESULT\n%s'):format(yaml.encode(result)))
+end)

From f0fb9f42a40dd00d187b9d6a6ea0e5e27d86c690 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Fri, 23 Feb 2018 20:07:37 +0300
Subject: [PATCH 07/26] move nullable function to utils as it is will be
 necessary for tests

---
 graphql/utils.lua | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/graphql/utils.lua b/graphql/utils.lua
index 1a472fa..e2df5db 100644
--- a/graphql/utils.lua
+++ b/graphql/utils.lua
@@ -132,4 +132,16 @@ function utils.gen_booking_table(data)
     })
 end
 
+-- XXX: recursive skip several NonNull's?
+function utils.nullable(gql_class)
+    assert(type(gql_class) == 'table', 'gql_class must be a table, got ' ..
+            type(gql_class))
+
+    if gql_class.__type ~= 'NonNull' then return gql_class end
+
+    assert(gql_class.ofType ~= nil, 'gql_class.ofType must not be nil')
+    return gql_class.ofType
+end
+
+
 return utils

From ac9f0ed5a3dbfdf59c7a66b113a9c0350b341f5e Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Fri, 23 Feb 2018 20:26:43 +0300
Subject: [PATCH 08/26] readability refactor; clean up comments; move nullable
 function to utils

---
 graphql/tarantool_graphql.lua | 56 +++++++++++++----------------------
 1 file changed, 20 insertions(+), 36 deletions(-)

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index be1e19c..64a3365 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -17,12 +17,13 @@ local execute = require('graphql.core.execute')
 
 local utils = require('graphql.utils')
 
+--local nullable = utils.nullable
+
 local tarantool_graphql = {}
 
 -- forward declarations
 local gql_type
 
---- Returns type of the top element in the avro schema
 local function avro_type(avro_schema)
     if type(avro_schema) == 'table' then
         if avro_schema.type == 'record' then
@@ -58,16 +59,7 @@ local function avro_type(avro_schema)
     error('unrecognized avro-schema type: ' .. json.encode(avro_schema))
 end
 
--- XXX: recursive skip several NonNull's?
-local function nullable(gql_class)
-    assert(type(gql_class) == 'table', 'gql_class must be a table, got ' ..
-        type(gql_class))
-
-    if gql_class.__type ~= 'NonNull' then return gql_class end
-
-    assert(gql_class.ofType ~= nil, 'gql_class.ofType must not be nil')
-    return gql_class.ofType
-end
+local nullable = utils.nullable
 
 local types_long = types.scalar({
     name = 'Long',
@@ -123,7 +115,7 @@ end
 --- Non-recursive version of the @{gql_type} function that returns
 --- InputObject instead of Object.
 --- An error will be raised in case of fields that are not scalar types
---- as there are no sense in non scalar arguments
+--- as there are no sense in non scalar arguments.
 local function gql_argument_type(state, avro_schema)
     assert(type(state) == 'table',
         'state must be a table, got ' .. type(state))
@@ -163,8 +155,6 @@ local function gql_argument_type(state, avro_schema)
         }))
 
         return res
-    --- elseif avro_type(avro_schema) == 'array' then
-
     else
         local res = convert_scalar_type(avro_schema, {raise = false})
         if res == nil then
@@ -175,17 +165,13 @@ local function gql_argument_type(state, avro_schema)
 end
 
 
---- Returns table of record's arguments
---- all arguments are nullable
+--- Recursively convert each field of an avro-schema to a graphql type and
+--- corresponding argument for an upper graphql type.
 ---
 --- @tparam table state
 --- @tparam table fields
---- @tparam table opts include is_for_args flag to specify
---- case when the function is used to collect arguments
-local function convert_record_fields_to_args(state, fields, opts)
+local function convert_record_fields_to_args(state, fields)
     local args = {}
-    local is_for_args = opts and opts.is_for_args or false
-
     for _, field in ipairs(fields) do
 
         assert(type(field.name) == 'string',
@@ -197,9 +183,8 @@ local function convert_record_fields_to_args(state, fields, opts)
         -- arrays (gql lists) and maps can't be arguments
         -- so these kinds are to be skipped
 
-        ---@todo consider case when gql_class is wrapper nonNull around List
-        --- or Map
-        if not(is_for_args and (gql_class == 'List' or gql_class == 'Map')) then
+        if (nullable(gql_class) ~= 'List'
+                            and nullable(gql_class) ~= 'Map') then
             args[field.name] = nullable(gql_class)
         end
     end
@@ -217,7 +202,8 @@ end
 local function convert_record_fields(state, fields, opts)
     local res = {}
     local object_args = {}
-    local is_for_args = opts and opts.is_for_args or false
+    local opts = opts or {}
+    local is_for_args = opts.is_for_args or false
 
     for _, field in ipairs(fields) do
         assert(type(field.name) == 'string',
@@ -231,19 +217,15 @@ local function convert_record_fields(state, fields, opts)
 
 
         -- arrays (gql lists) and maps can't be arguments
-        -- so these kinds are to be skipped
-
-        ---@todo consider case when gql_class is wrapper nonNull around List
-        --- or Map
-        if not (is_for_args and (res[field.name].kind == 'List'
-                            or res[field.name].kind == 'Map')) then
+        if not is_for_args or (nullable(res[field.name].kind) ~= 'List'
+                            and nullable(res[field.name].kind) ~= 'Map') then
             object_args[field.name] = nullable(res[field.name].kind)
         end
     end
     return res, object_args
 end
 
---- The function recursively converts passed avro-schema to a graphql type (kind)
+--- The function recursively converts passed avro-schema to a graphql type (kind).
 ---
 --- @tparam table state for read state.accessor and previously filled
 --- state.types (state.types are gql types)
@@ -518,7 +500,7 @@ local function parse_cfg(cfg)
 end
 
 --- The function checks if given query has an appropriate type 'query'
---- (mutations are not supported yet)
+--- (mutations are not supported yet).
 local function assert_gql_query_ast(func_name, ast)
     assert(#ast.definitions == 1,
         func_name .. ': expected an one query')
@@ -530,7 +512,8 @@ local function assert_gql_query_ast(func_name, ast)
         type(operation_name))
 end
 
---- The function just makes some assertions and then call graphql-lua execute
+--- The function just makes some reasonable assertions on input
+--- and then call graphql-lua execute.
 local function gql_execute(qstate, variables)
     assert(qstate.state)
     local state = qstate.state
@@ -549,7 +532,8 @@ local function gql_execute(qstate, variables)
 end
 
 --- The function parses a raw query string, validate the resulting query
---- and return it ready for execution
+--- and make it ready for execution.
+---
 --- @tparam table state current state of graphql-lib, including
 --- schemas, collections and accessor
 --- @tparam string query raw query string
@@ -649,4 +633,4 @@ function tarantool_graphql.new(cfg)
     })
 end
 
-return tarantool_graphql
\ No newline at end of file
+return tarantool_graphql

From 8110208eeac03c6c2ca9932e1c0fb9276b974cce Mon Sep 17 00:00:00 2001
From: Ivan Koptelov <ivan.koptelov@phystech.edu>
Date: Fri, 23 Feb 2018 20:30:26 +0300
Subject: [PATCH 09/26] Update tarantool_graphql.lua

---
 graphql/tarantool_graphql.lua | 2 --
 1 file changed, 2 deletions(-)

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index 64a3365..83b0bcd 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -17,8 +17,6 @@ local execute = require('graphql.core.execute')
 
 local utils = require('graphql.utils')
 
---local nullable = utils.nullable
-
 local tarantool_graphql = {}
 
 -- forward declarations

From 043d6f9487bca644bb700f50096d033dd012ac9b Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Sun, 25 Feb 2018 22:41:20 +0300
Subject: [PATCH 10/26] small style fixes

---
 graphql/tarantool_graphql.lua | 41 +++++++++++++----------------------
 1 file changed, 15 insertions(+), 26 deletions(-)

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index 83b0bcd..e2cbbdd 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -96,24 +96,20 @@ local function convert_scalar_type(avro_schema, opts)
         return types.string
     end
 
-    if opts.is_items_type then
-        error('avro array items must have know scalar type, not: ' ..
-                json.encode(avro_schema))
-    end
-
     if raise then
         error('unrecognized avro-schema scalar type: ' ..
         json.encode(avro_schema))
     end
 
-
     return nil
 end
 
 --- Non-recursive version of the @{gql_type} function that returns
 --- InputObject instead of Object.
---- An error will be raised in case of fields that are not scalar types
---- as there are no sense in non scalar arguments.
+--- An error will be raised if avro_schema type is 'record'
+--- and its' fields are not scalar type because currently
+--- triple nesting level (record with record as a field - ok,
+--- record with record wich has inside another level - not ok)
 local function gql_argument_type(state, avro_schema)
     assert(type(state) == 'table',
         'state must be a table, got ' .. type(state))
@@ -131,7 +127,6 @@ local function gql_argument_type(state, avro_schema)
 
         local fields = {}
         for _, field in ipairs(avro_schema.fields) do
-
             assert(type(field.name) == 'string',
                 ('field.name must be a string, got %s (schema %s)')
                 :format(type(field.name), json.encode(field)))
@@ -163,15 +158,17 @@ local function gql_argument_type(state, avro_schema)
 end
 
 
---- Recursively convert each field of an avro-schema to a graphql type and
---- corresponding argument for an upper graphql type.
+-- Convert list of fields in the avro-schema format to list of GraphQL types
+-- with intention to use it as GraphQL arguments later.
+-- It uses the @{gql_argument_type} function to convert each field, then skips
+-- fields of array and map types and gives the resulting list of converted fields.
 ---
---- @tparam table state
---- @tparam table fields
+--- @tparam table state for read state.accessor and previously filled
+--- state.types
+--- @tparam table fields fields part from an avro-schema
 local function convert_record_fields_to_args(state, fields)
     local args = {}
     for _, field in ipairs(fields) do
-
         assert(type(field.name) == 'string',
             ('field.name must be a string, got %s (schema %s)')
             :format(type(field.name), json.encode(field)))
@@ -179,10 +176,8 @@ local function convert_record_fields_to_args(state, fields)
         local gql_class = gql_argument_type(state, field.type)
 
         -- arrays (gql lists) and maps can't be arguments
-        -- so these kinds are to be skipped
-
-        if (nullable(gql_class) ~= 'List'
-                            and nullable(gql_class) ~= 'Map') then
+        -- so these graphql types are to be skipped
+        if nullable(gql_class) ~= 'List' and nullable(gql_class) ~= 'Map' then
             args[field.name] = nullable(gql_class)
         end
     end
@@ -213,7 +208,6 @@ local function convert_record_fields(state, fields, opts)
             kind = gql_type(state, field.type),
         }
 
-
         -- arrays (gql lists) and maps can't be arguments
         if not is_for_args or (nullable(res[field.name].kind) ~= 'List'
                             and nullable(res[field.name].kind) ~= 'Map') then
@@ -223,7 +217,7 @@ local function convert_record_fields(state, fields, opts)
     return res, object_args
 end
 
---- The function recursively converts passed avro-schema to a graphql type (kind).
+--- The function converts passed avro-schema to a GraphQL type.
 ---
 --- @tparam table state for read state.accessor and previously filled
 --- state.types (state.types are gql types)
@@ -379,15 +373,13 @@ gql_type = function(state, avro_schema, collection, collection_name)
         error('enums not implemented yet') -- XXX
 
     elseif avro_t == 'array' or avro_t == 'array*' then
-
         assert(avro_schema.items ~= nil,
             'items field must not be nil in array avro schema')
         assert(type(avro_schema.items) == 'string',
             'avro_schema.items must be a string, got ' .. type(avro_schema.item))
 
         local gql_items_type = convert_scalar_type(avro_schema.items,
-            {is_items_type=true, raise=true})
-
+            {raise=true})
         local gql_array = types.list(gql_items_type)
 
         if  avro_t == 'array*' then
@@ -397,16 +389,13 @@ gql_type = function(state, avro_schema, collection, collection_name)
         if avro_t == 'array' then
             return types.nonNull(gql_array)
         end
-
     else
         local res = convert_scalar_type(avro_schema, {raise = false})
         if res == nil then
             error('unrecognized avro-schema type: ' .. json.encode(avro_schema))
         end
         return res
-
     end
-
 end
 
 

From 7714393a4d3aae1195797c553791a01967cfe6f4 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Mon, 26 Feb 2018 11:44:19 +0300
Subject: [PATCH 11/26] readability and comments fixes

---
 graphql/tarantool_graphql.lua | 66 ++++++++++++++++-------------------
 1 file changed, 31 insertions(+), 35 deletions(-)

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index e2cbbdd..1874b2b 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -195,8 +195,6 @@ end
 local function convert_record_fields(state, fields, opts)
     local res = {}
     local object_args = {}
-    local opts = opts or {}
-    local is_for_args = opts.is_for_args or false
 
     for _, field in ipairs(fields) do
         assert(type(field.name) == 'string',
@@ -209,8 +207,9 @@ local function convert_record_fields(state, fields, opts)
         }
 
         -- arrays (gql lists) and maps can't be arguments
-        if not is_for_args or (nullable(res[field.name].kind) ~= 'List'
-                            and nullable(res[field.name].kind) ~= 'Map') then
+        local avro_t = avro_type(field.type)
+        if avro_t ~= 'array' and avro_t ~= 'array*' and avro_t ~= 'map'
+                and avro_t ~= 'map*' then
             object_args[field.name] = nullable(res[field.name].kind)
         end
     end
@@ -231,6 +230,10 @@ end
 ---    automatically generate corresponding decucible fields.
 --- 2. The collection name will be used as the resulting graphql type name
 ---    instead of the avro-schema name.
+---
+--- XXX As it is not clear now what to do with complex types inside arrays
+---(just pass to results or allow to use filters), only scalar arrays
+--- is allowed for now.
 gql_type = function(state, avro_schema, collection, collection_name)
     assert(type(state) == 'table',
         'state must be a table, got ' .. type(state))
@@ -253,7 +256,7 @@ gql_type = function(state, avro_schema, collection, collection_name)
     assert(accessor.list_args ~= nil,
         'state.accessor.list_args must not be nil')
 
-    -- type of the top element in the avro schema
+    -- type of the top element in the avro-schema
     local avro_t = avro_type(avro_schema)
 
     if avro_t == 'record' or avro_t == 'record*' then
@@ -299,7 +302,6 @@ gql_type = function(state, avro_schema, collection, collection_name)
 
             local c_list_args = state.list_arguments[c.destination_collection]
 
-            -- change fields that are represented by connections
             fields[c.name] = {
                 name = c.name,
                 kind = destination_type,
@@ -309,7 +311,6 @@ gql_type = function(state, avro_schema, collection, collection_name)
                     local destination_args_values = {}
 
                     for _, part in ipairs(c.parts) do
-
                         assert(type(part.source_field) == 'string',
                             'part.source_field must be a string, got ' ..
                             type(part.destination_field))
@@ -322,6 +323,7 @@ gql_type = function(state, avro_schema, collection, collection_name)
                         destination_args_values[#destination_args_values + 1] =
                             parent[part.source_field]
                     end
+
                     local from = {
                         collection_name = collection_name,
                         connection_name = c.name,
@@ -360,7 +362,7 @@ gql_type = function(state, avro_schema, collection, collection_name)
             }
         end
 
-        -- create gql schema
+        -- create gql type
         local res = types.object({
             name = collection ~= nil and collection.name or avro_schema.name,
             description = 'generated from avro-schema for ' ..
@@ -368,27 +370,21 @@ gql_type = function(state, avro_schema, collection, collection_name)
             fields = fields,
         })
         return avro_t == 'enum' and types.nonNull(res) or res
-
     elseif avro_t == 'enum' then
         error('enums not implemented yet') -- XXX
-
     elseif avro_t == 'array' or avro_t == 'array*' then
         assert(avro_schema.items ~= nil,
             'items field must not be nil in array avro schema')
         assert(type(avro_schema.items) == 'string',
-            'avro_schema.items must be a string, got ' .. type(avro_schema.item))
-
-        local gql_items_type = convert_scalar_type(avro_schema.items,
-            {raise=true})
-        local gql_array = types.list(gql_items_type)
+            'avro_schema.items must be a string, got '
+                .. type(avro_schema.item))
 
-        if  avro_t == 'array*' then
-            return gql_array
-        end
+        local gql_items_type = convert_scalar_type(avro_schema.items)
 
-        if avro_t == 'array' then
-            return types.nonNull(gql_array)
-        end
+        assert(gql_items_type, "only scalars are supported as array items for now,
+            and " .. avro_type(avro_schema.items) .. " is not a scalar")
+        local gql_array = types.list(gql_items_type)
+        return avro_t == 'array' and types.nonNull(gql_array) or gql_array
     else
         local res = convert_scalar_type(avro_schema, {raise = false})
         if res == nil then
@@ -398,7 +394,6 @@ gql_type = function(state, avro_schema, collection, collection_name)
     end
 end
 
-
 local function parse_cfg(cfg)
     local state = {}
     state.types = utils.gen_booking_table({})
@@ -434,18 +429,18 @@ local function parse_cfg(cfg)
 
         -- recursively converts all avro types into gql types in the given schema
         assert(schema.type == 'record',
-            'top-level schema must have record avro type, not' .. schema.type)
-        state.types[collection_name] = gql_type(state, schema, collection, collection_name)
+            'top-level schema must have record avro type, not'
+                .. schema.type)
+        state.types[collection_name] = gql_type(state, schema, collection,
+            collection_name)
 
-        -- prepare arguments (their kinds)
+        -- prepare arguments' types
         local _, object_args = convert_record_fields(state,
-            schema.fields, {is_for_args=true})
+            schema.fields)
         local list_args = convert_record_fields_to_args(
-            state, accessor:list_args(collection_name), {is_for_args=true})
+            state, accessor:list_args(collection_name))
         local args = utils.merge_tables(object_args, list_args)
 
-        -- list and map (avro array and map) can't be arguments
-
         state.object_arguments[collection_name] = object_args
         state.list_arguments[collection_name] = list_args
         state.all_arguments[collection_name] = args
@@ -486,8 +481,9 @@ local function parse_cfg(cfg)
     return state
 end
 
---- The function checks if given query has an appropriate type 'query'
---- (mutations are not supported yet).
+--- The function checks that one and only one GraphQL operation
+--- (query/mutation/subscription) is defined in the AST and it's type
+--- is 'query' as mutations and subscriptions are not supported yet
 local function assert_gql_query_ast(func_name, ast)
     assert(#ast.definitions == 1,
         func_name .. ': expected an one query')
@@ -518,10 +514,10 @@ local function gql_execute(qstate, variables)
         operation_name)
 end
 
---- The function parses a raw query string, validate the resulting query
---- and make it ready for execution.
----
---- @tparam table state current state of graphql-lib, including
+--- The function parses a query string, validate the resulting query
+--- against the GraphQL schema and provides an object with the function to
+--- execute the query with specific variables values
+--- @tparam table state current state of graphql, including
 --- schemas, collections and accessor
 --- @tparam string query raw query string
 local function gql_compile(state, query)

From 470e8e101be844fdb99e435ce76d4e3c2cf4ab47 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Mon, 26 Feb 2018 11:44:57 +0300
Subject: [PATCH 12/26] remove excess test

---
 test/local/simple_array.result   |  7 ---
 test/local/simple_array.test.lua | 95 --------------------------------
 2 files changed, 102 deletions(-)
 delete mode 100644 test/local/simple_array.result
 delete mode 100644 test/local/simple_array.test.lua

diff --git a/test/local/simple_array.result b/test/local/simple_array.result
deleted file mode 100644
index a3f6c68..0000000
--- a/test/local/simple_array.result
+++ /dev/null
@@ -1,7 +0,0 @@
-RESULT
----
-user_collection:
-- user_id: def
-  favs:
-    - potato
-    - fruit
\ No newline at end of file
diff --git a/test/local/simple_array.test.lua b/test/local/simple_array.test.lua
deleted file mode 100644
index 8a1ee82..0000000
--- a/test/local/simple_array.test.lua
+++ /dev/null
@@ -1,95 +0,0 @@
-#!/usr/bin/env tarantool
-
-local fio = require('fio')
-
--- require in-repo version of graphql/ sources despite current working directory
-package.path = fio.abspath(debug.getinfo(1).source:match("@?(.*/)")
-                                :gsub('/./', '/'):gsub('/+$', '')) .. '/../../?.lua' .. ';' ..
-        package.path
-
-local json = require('json')
-local yaml = require('yaml')
-local graphql = require('graphql')
-local utils = require('graphql.utils')
-
-local schemas = json.decode([[{
-    "user": {
-        "name": "user",
-        "type": "record",
-        "fields": [
-            { "name": "id", "type": "string" },
-            { "name": "favs", "type": { "type": "array", "items": "string" } }
-        ]
-    }
-}]])
-
-local collections = json.decode([[{
-    "user_collection": {
-        "schema_name": "user"
-}]])
-
-local function access_function(parent, collection_name, filter, args)
-    --[[
-    print('DEBUG: collection_name: ' .. collection_name)
-    print('DEBUG: filter: ' .. json.encode(filter))
-    print('DEBUG: args: ' .. json.encode(args))
-    print('DEBUG: --------')
-    --]]
-    local obj
-    if collection_name == 'user_collection' then
-        obj = {
-            user_id = 'def',
-            favs = {'potato', 'fruit'}
-        }
-    else
-        error('NIY: ' .. collection_name)
-    end
-    if not utils.is_subtable(obj, filter) then
-        return {}
-    end
-    return { obj }
-end
-
-local accessor = setmetatable({}, {
-    __index = {
-        select = function(self, parent, collection_name, connection_name,
-                          filter, args)
-            return access_function(parent, collection_name, filter, args)
-        end,
-        list_args = function(self, connection_type)
-            if connection_type == '1:1' then
-                return {}
-            end
-            return {
-                { name = 'limit', type = 'int' },
-                { name = 'offset', type = 'long' },
-            -- {name = 'filter', type = ...},
-            }
-        end,
-    }
-})
-
-local gql_wrapper = graphql.new({
--- class_name:class mapping
-    schemas = schemas,
--- collection_{schema_name=..., connections=...} mapping
-    collections = collections,
--- :select() and :list_args() provider
-    accessor = accessor,
-})
-
-local query_1 = [[
-    query obtainUserFavs($user_id: String) {
-        user_collection(user_id: $user_id, type: "type 1", size: 2) {
-            id
-            favs
-        }
-    }
-]]
-
-utils.show_trace(function()
-    local variables_1 = { user_id = 'def' }
-    local gql_query_1 = gql_wrapper:compile(query_1)
-    local result = gql_query_1:execute(variables_1)
-    print(('RESULT\n%s'):format(yaml.encode(result)))
-end)

From 0160c690fb797a354533b8ba5774f591d01f7efb Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Mon, 26 Feb 2018 11:46:30 +0300
Subject: [PATCH 13/26] remove redundant 'map' test cases

---
 test/local/array_and_map.result   |  9 --------
 test/local/array_and_map.test.lua | 38 ++-----------------------------
 2 files changed, 2 insertions(+), 45 deletions(-)

diff --git a/test/local/array_and_map.result b/test/local/array_and_map.result
index f2614db..da7035d 100644
--- a/test/local/array_and_map.result
+++ b/test/local/array_and_map.result
@@ -7,12 +7,3 @@ user_collection:
   - potato
 ...
 
-RESULT
----
-organization_collection:
-- organization_id: def
-  organization_events:
-    holiday: nice holiday
-    new_year: hey hou
-...
-
diff --git a/test/local/array_and_map.test.lua b/test/local/array_and_map.test.lua
index 10b85e5..e2bb119 100755
--- a/test/local/array_and_map.test.lua
+++ b/test/local/array_and_map.test.lua
@@ -20,23 +20,12 @@ local schemas = json.decode([[{
             { "name": "user_id", "type": "string" },
             { "name": "favorite_food", "type": {"type": "array", "items": "string"} }
         ]
-    },
-    "organization": {
-        "name": "organization",
-        "type": "record",
-        "fields": [
-            { "name": "organization_id", "type": "string" },
-            { "name": "organization_events", "type": {"type": "map", "values": "string"} }
-        ]
-    }
-}]])
+        }
+    }]])
 
 local collections = json.decode([[{
     "user_collection": {
         "schema_name": "user"
-    },
-    "organization_collection": {
-        "schema_name": "organization"
     }
 }]])
 
@@ -53,12 +42,6 @@ local function access_function(parent, collection_name, filter, args)
             user_id = 'def',
             favorite_food = { 'meat', 'potato' },
         }
-    elseif collection_name == 'organization_collection' then
-        obj = {
-            organization_id = 'def',
-            organization_events = { holiday = 'nice holiday',
-                                    new_year = 'hey hou' },
-        }
     else
         error('NIY: ' .. collection_name)
     end
@@ -105,17 +88,6 @@ local query_with_list = [[
     }
 ]]
 
-
-local query_with_map = [[
-    query obtainOrganizationEvents($organization_id: String) {
-        organization_collection(organization_id: $organization_id) {
-            organization_id,
-            organization_events
-        }
-    }
-]]
-
-
 utils.show_trace(function()
     local variables_2 = { user_id = 'def' }
     local gql_query_2 = gql_wrapper:compile(query_with_list)
@@ -123,9 +95,3 @@ utils.show_trace(function()
     print(('RESULT\n%s'):format(yaml.encode(result)))
 end)
 
-utils.show_trace(function()
-    local variables_1 = {organization_id = 'def'}
-    local gql_query_1 = gql_wrapper:compile(query_with_map)
-    local result = gql_query_1:execute(variables_1)
-    print(('RESULT\n%s'):format(yaml.encode(result)))
-end)

From 19b8d8b3a4c5b861509e922f9ba9aca9f51b9823 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Mon, 26 Feb 2018 13:52:53 +0300
Subject: [PATCH 14/26] fix small error; now general convert_scalar_type
 accepts nil as opt

---
 graphql/tarantool_graphql.lua | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index 1874b2b..a0d2485 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -78,7 +78,7 @@ local function convert_scalar_type(avro_schema, opts)
     assert(type(opts) == 'table', 'opts must be nil or table, got ' ..
         type(opts))
     local raise = opts.raise or false
-    assert(type(opts.raise) == 'boolean', 'opts.raise must be boolean, got ' ..
+    assert(type(raise) == 'boolean', 'opts.raise must be boolean, got ' ..
         type(opts.raise))
 
     local avro_t = avro_type(avro_schema)
@@ -381,8 +381,8 @@ gql_type = function(state, avro_schema, collection, collection_name)
 
         local gql_items_type = convert_scalar_type(avro_schema.items)
 
-        assert(gql_items_type, "only scalars are supported as array items for now,
-            and " .. avro_type(avro_schema.items) .. " is not a scalar")
+        assert(gql_items_type, "only scalars are supported as array items for now "
+            .. avro_type(avro_schema.items) .. " is not a scalar")
         local gql_array = types.list(gql_items_type)
         return avro_t == 'array' and types.nonNull(gql_array) or gql_array
     else

From 1377c751981e683c3ae5d38d9e42c9d1a7b5b5e5 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Mon, 26 Feb 2018 19:34:32 +0300
Subject: [PATCH 15/26] add test for avro-array usage (with space accessor);

---
 test/local/avro_array.result                  |   9 ++
 test/local/avro_array.test.lua                |  57 +++++++++
 ...nd_map.result => simple_avro_array.result} |   0
 ...ap.test.lua => simple_avro_array.test.lua} |  15 +--
 test/testdata/array_and_map_testdata.lua      | 113 ++++++++++++++++++
 5 files changed, 187 insertions(+), 7 deletions(-)
 create mode 100644 test/local/avro_array.result
 create mode 100755 test/local/avro_array.test.lua
 rename test/local/{array_and_map.result => simple_avro_array.result} (100%)
 rename test/local/{array_and_map.test.lua => simple_avro_array.test.lua} (84%)
 create mode 100755 test/testdata/array_and_map_testdata.lua

diff --git a/test/local/avro_array.result b/test/local/avro_array.result
new file mode 100644
index 0000000..6b6cdbb
--- /dev/null
+++ b/test/local/avro_array.result
@@ -0,0 +1,9 @@
+RESULT
+---
+user_collection:
+- user_id: user_id_1
+  favorite_food:
+  - meat
+  - potato
+...
+
diff --git a/test/local/avro_array.test.lua b/test/local/avro_array.test.lua
new file mode 100755
index 0000000..24f25ec
--- /dev/null
+++ b/test/local/avro_array.test.lua
@@ -0,0 +1,57 @@
+#!/usr/bin/env tarantool
+
+box.cfg{background = false}
+local fio = require('fio')
+
+-- require in-repo version of graphql/ sources despite current working directory
+package.path = fio.abspath(debug.getinfo(1).source:match("@?(.*/)")
+   :gsub('/./', '/'):gsub('/+$', '')) .. '/../../?.lua' .. ';' ..
+package.path
+
+local graphql = require('graphql')
+local testdata = require('test.testdata.array_and_map_testdata')
+
+-- init box, upload test data and acquire metadata
+-- -----------------------------------------------
+
+
+-- init box and data schema
+testdata.init_spaces()
+
+-- upload test data
+testdata.fill_test_data()
+
+-- acquire metadata
+local metadata = testdata.get_test_metadata()
+local schemas = metadata.schemas
+local collections = metadata.collections
+local service_fields = metadata.service_fields
+local indexes = metadata.indexes
+
+-- build accessor and graphql schemas
+-- ----------------------------------
+
+local accessor = graphql.accessor_space.new({
+    schemas = schemas,
+    collections = collections,
+    service_fields = service_fields,
+    indexes = indexes,
+})
+
+local gql_wrapper = graphql.new({
+    schemas = schemas,
+    collections = collections,
+    accessor = accessor,
+})
+
+-- run queries
+-- -----------
+
+testdata.run_queries(gql_wrapper)
+
+-- clean up
+-- --------
+
+testdata.drop_spaces()
+
+os.exit()
diff --git a/test/local/array_and_map.result b/test/local/simple_avro_array.result
similarity index 100%
rename from test/local/array_and_map.result
rename to test/local/simple_avro_array.result
diff --git a/test/local/array_and_map.test.lua b/test/local/simple_avro_array.test.lua
similarity index 84%
rename from test/local/array_and_map.test.lua
rename to test/local/simple_avro_array.test.lua
index e2bb119..257cc8c 100755
--- a/test/local/array_and_map.test.lua
+++ b/test/local/simple_avro_array.test.lua
@@ -2,11 +2,12 @@
 
 local fio = require('fio')
 
--- require in-repo version of graphql/ sources despite current working directory
+ --require in-repo version of graphql/ sources despite current working directory
 package.path = fio.abspath(debug.getinfo(1).source:match("@?(.*/)")
                                 :gsub('/./', '/'):gsub('/+$', '')) .. '/../../?.lua' .. ';' ..
         package.path
 
+
 local json = require('json')
 local yaml = require('yaml')
 local graphql = require('graphql')
@@ -29,7 +30,7 @@ local collections = json.decode([[{
     }
 }]])
 
-local function access_function(parent, collection_name, filter, args)
+local function simple_access_function(parent, collection_name, filter, args)
     --[[
     print('DEBUG: collection_name: ' .. collection_name)
     print('DEBUG: filter: ' .. json.encode(filter))
@@ -51,11 +52,11 @@ local function access_function(parent, collection_name, filter, args)
     return { obj }
 end
 
-local accessor = setmetatable({}, {
+local simple_accessor = setmetatable({}, {
     __index = {
         select = function(self, parent, collection_name, connection_name,
                           filter, args)
-            return access_function(parent, collection_name, filter, args)
+            return simple_access_function(parent, collection_name, filter, args)
         end,
         list_args = function(self, connection_type)
             if connection_type == '1:1' then
@@ -70,13 +71,13 @@ local accessor = setmetatable({}, {
     }
 })
 
-local gql_wrapper = graphql.new({
+local gql_wrapper_simple_accessor = graphql.new({
 -- class_name:class mapping
     schemas = schemas,
 -- collection_{schema_name=..., connections=...} mapping
     collections = collections,
 -- :select() and :list_args() provider
-    accessor = accessor,
+    accessor = simple_accessor,
 })
 
 local query_with_list = [[
@@ -90,7 +91,7 @@ local query_with_list = [[
 
 utils.show_trace(function()
     local variables_2 = { user_id = 'def' }
-    local gql_query_2 = gql_wrapper:compile(query_with_list)
+    local gql_query_2 = gql_wrapper_simple_accessor:compile(query_with_list)
     local result = gql_query_2:execute(variables_2)
     print(('RESULT\n%s'):format(yaml.encode(result)))
 end)
diff --git a/test/testdata/array_and_map_testdata.lua b/test/testdata/array_and_map_testdata.lua
new file mode 100755
index 0000000..c264b9c
--- /dev/null
+++ b/test/testdata/array_and_map_testdata.lua
@@ -0,0 +1,113 @@
+local json = require('json')
+local yaml = require('yaml')
+local utils = require('graphql.utils')
+
+local array_testdata = {}
+
+local function print_and_return(...)
+    print(...)
+    return table.concat({ ... }, ' ') .. '\n'
+end
+
+function array_testdata.get_test_metadata()
+
+    local schemas = json.decode([[{
+    "user": {
+        "name": "user",
+        "type": "record",
+        "fields": [
+            { "name": "user_id", "type": "string" },
+            { "name": "favorite_food", "type": {"type": "array", "items": "string"} }
+        ]
+        }
+    }]])
+
+    local collections = json.decode([[{
+    "user_collection": {
+        "schema_name": "user",
+        "connections": []
+    }
+}]])
+
+    local service_fields = {
+        user = {
+            { name = 'expires_on', type = 'long', default = 0 },
+        },
+        order = {},
+    }
+
+    local indexes = {
+        user_collection = {
+            user_id_index = {
+                service_fields = {},
+                fields = { 'user_id' },
+                index_type = 'tree',
+                unique = true,
+                primary = true,
+            },
+        }
+    }
+
+    return {
+        schemas = schemas,
+        collections = collections,
+        service_fields = service_fields,
+        indexes = indexes,
+    }
+end
+
+function array_testdata.init_spaces()
+    -- user_collection fields
+    local U_USER_ID_FN = 2
+
+    box.once('test_space_init_spaces', function()
+        box.schema.create_space('user_collection')
+        box.space.user_collection:create_index('user_id_index',
+            { type = 'tree', unique = true, parts = {
+                U_USER_ID_FN, 'string'
+            } }
+        )
+    end)
+end
+
+function array_testdata.fill_test_data(shard)
+    local shard = shard or box.space
+
+    shard.user_collection:replace(
+        { 1827767717, 'user_id_1', { 'meat', 'potato' } })
+    shard.user_collection:replace(
+        { 1827767717, 'user_id_2', { 'fruit' } })
+    --@todo add empty array
+end
+
+function array_testdata.drop_spaces()
+    box.space._schema:delete('oncetest_space_init_spaces')
+    box.space.user_collection:drop()
+end
+
+function array_testdata.run_queries(gql_wrapper)
+
+    local results = ''
+
+    local query_1 = [[
+        query user_favorites($user_id: String) {
+            user_collection(user_id: $user_id) {
+                user_id
+                favorite_food
+            }
+        }
+    ]]
+
+    --assert(false, 'err')
+    utils.show_trace(function()
+        local variables_1 = { user_id = 'user_id_1' }
+        local gql_query_1 = gql_wrapper:compile(query_1)
+        local result = gql_query_1:execute(variables_1)
+        results = results .. print_and_return(
+            ('RESULT\n%s'):format(yaml.encode(result)))
+    end)
+
+    return results
+end
+
+return array_testdata

From 5af08d8fd49ef8e19bc8b95da540901feec11dea Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Mon, 26 Feb 2018 19:52:41 +0300
Subject: [PATCH 16/26] move nullable back to tarantool_graphql from utils

---
 graphql/tarantool_graphql.lua | 11 ++++++++++-
 graphql/utils.lua             | 12 ------------
 2 files changed, 10 insertions(+), 13 deletions(-)
 mode change 100644 => 100755 graphql/utils.lua

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index a0d2485..ee2a0dd 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -57,7 +57,16 @@ local function avro_type(avro_schema)
     error('unrecognized avro-schema type: ' .. json.encode(avro_schema))
 end
 
-local nullable = utils.nullable
+-- XXX: recursive skip several NonNull's?
+local function nullable(gql_class)
+    assert(type(gql_class) == 'table', 'gql_class must be a table, got ' ..
+        type(gql_class))
+
+    if gql_class.__type ~= 'NonNull' then return gql_class end
+
+    assert(gql_class.ofType ~= nil, 'gql_class.ofType must not be nil')
+    return gql_class.ofType
+end
 
 local types_long = types.scalar({
     name = 'Long',
diff --git a/graphql/utils.lua b/graphql/utils.lua
old mode 100644
new mode 100755
index e2df5db..1a472fa
--- a/graphql/utils.lua
+++ b/graphql/utils.lua
@@ -132,16 +132,4 @@ function utils.gen_booking_table(data)
     })
 end
 
--- XXX: recursive skip several NonNull's?
-function utils.nullable(gql_class)
-    assert(type(gql_class) == 'table', 'gql_class must be a table, got ' ..
-            type(gql_class))
-
-    if gql_class.__type ~= 'NonNull' then return gql_class end
-
-    assert(gql_class.ofType ~= nil, 'gql_class.ofType must not be nil')
-    return gql_class.ofType
-end
-
-
 return utils

From be8457c434444344c74e9bab5f358caf1dee4cf7 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Tue, 27 Feb 2018 11:29:46 +0300
Subject: [PATCH 17/26] add support of avro map and test for simple case with
 scalar map values and mock accessor

---
 graphql/tarantool_graphql.lua            |  28 ++++++-
 test/local/simple_avro_map.result        |   9 ++
 test/local/simple_avro_map.test.lua      | 102 +++++++++++++++++++++++
 test/testdata/array_and_map_testdata.lua |  24 +++---
 4 files changed, 150 insertions(+), 13 deletions(-)
 create mode 100644 test/local/simple_avro_map.result
 create mode 100755 test/local/simple_avro_map.test.lua

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index ee2a0dd..1b90281 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -80,6 +80,20 @@ local types_long = types.scalar({
     end
 })
 
+local types_map = types.scalar({
+    name = 'Map',
+    description = 'Map is a dictionary with string keys and values of ' ..
+        'arbitrary but same among all values type',
+    serialize = function(value) return value end,
+    parseValue = function(value)return value end,
+    -- node == ast
+    parseLiteral = function(node)
+        if node.kind == 'Map' then
+            return node.value
+        end
+    end
+})
+
 -- XXX: boolean
 -- XXX: float
 local function convert_scalar_type(avro_schema, opts)
@@ -394,6 +408,18 @@ gql_type = function(state, avro_schema, collection, collection_name)
             .. avro_type(avro_schema.items) .. " is not a scalar")
         local gql_array = types.list(gql_items_type)
         return avro_t == 'array' and types.nonNull(gql_array) or gql_array
+    elseif avro_t == 'map' or avro_t == 'map*' then
+        assert(avro_schema.values ~= nil,
+            'values must not be nil in map avro schema')
+        assert(type(avro_schema.values) == 'table'
+            or type(avro_schema.values) == 'string',
+            ('avro_schema.values must be a table or a string,' ..
+            'got %s (avro_schema %s)'):format(type(avro_schema.values),
+            json.encode(avro_schema)))
+
+        convert_scalar_type(avro_schema.values, {raise = true})
+        local gql_map = types_map
+        return avro_t == 'map' and types.nonNull(gql_map) or gql_map
     else
         local res = convert_scalar_type(avro_schema, {raise = false})
         if res == nil then
@@ -438,7 +464,7 @@ local function parse_cfg(cfg)
 
         -- recursively converts all avro types into gql types in the given schema
         assert(schema.type == 'record',
-            'top-level schema must have record avro type, not'
+            'top-level schema must have record avro type, not '
                 .. schema.type)
         state.types[collection_name] = gql_type(state, schema, collection,
             collection_name)
diff --git a/test/local/simple_avro_map.result b/test/local/simple_avro_map.result
new file mode 100644
index 0000000..a3982bd
--- /dev/null
+++ b/test/local/simple_avro_map.result
@@ -0,0 +1,9 @@
+RESULT
+---
+user_collection:
+- user_id: def
+  favorite_holidays:
+    december: new year
+    march: vacation
+...
+
diff --git a/test/local/simple_avro_map.test.lua b/test/local/simple_avro_map.test.lua
new file mode 100755
index 0000000..029e6fa
--- /dev/null
+++ b/test/local/simple_avro_map.test.lua
@@ -0,0 +1,102 @@
+#!/usr/bin/env tarantool
+
+local fio = require('fio')
+
+--require in-repo version of graphql/ sources despite current working directory
+package.path = fio.abspath(debug.getinfo(1).source:match("@?(.*/)")
+    :gsub('/./', '/'):gsub('/+$', '')) .. '/../../?.lua' .. ';' ..
+    package.path
+
+local json = require('json')
+local yaml = require('yaml')
+local graphql = require('graphql')
+local utils = require('graphql.utils')
+
+local schemas = json.decode([[{
+    "user": {
+        "name": "user",
+        "type": "record",
+        "fields": [
+            { "name": "user_id", "type": "string" },
+            { "name": "favorite_holidays", "type": {"type": "map", "values": "string"} }
+        ]
+    }
+}]])
+
+local collections = json.decode([[{
+    "user_collection": {
+        "schema_name": "user"
+    }
+}]])
+
+local function simple_access_function(parent, collection_name, filter, args)
+    --[[
+    print('DEBUG: collection_name: ' .. collection_name)
+    print('DEBUG: filter: ' .. json.encode(filter))
+    print('DEBUG: args: ' .. json.encode(args))
+    print('DEBUG: --------')
+    --]]
+    local obj
+    if collection_name == 'user_collection' then
+        obj = {
+            user_id = 'def',
+            favorite_holidays = { december = 'new year', march = 'vacation' }
+        }
+    else
+        error('NIY: ' .. collection_name)
+    end
+    if not utils.is_subtable(obj, filter) then
+        return {}
+    end
+    return { obj }
+end
+
+local simple_accessor = setmetatable({}, {
+    __index = {
+        select = function(self, parent, collection_name, connection_name,
+                          filter, args)
+            return simple_access_function(parent, collection_name, filter, args)
+        end,
+        list_args = function(self, connection_type)
+            if connection_type == '1:1' then
+                return {}
+            end
+            return {
+                { name = 'limit', type = 'int' },
+                { name = 'offset', type = 'long' },
+            -- {name = 'filter', type = ...},
+            }
+        end,
+    }
+})
+
+local gql_wrapper_simple_accessor
+local query_with_map
+utils.show_trace(function()
+    gql_wrapper_simple_accessor = graphql.new({
+    -- class_name:class mapping
+        schemas = schemas,
+    -- collection_{schema_name=..., connections=...} mapping
+        collections = collections,
+    -- :select() and :list_args() provider
+        accessor = simple_accessor,
+    })
+
+    query_with_map = [[
+        query userFavs($user_id: String) {
+            user_collection(user_id: $user_id) {
+                user_id
+                favorite_holidays
+            }
+        }
+    ]]
+
+end
+)
+
+utils.show_trace(function()
+    local variables_2 = { user_id = 'def' }
+    local gql_query_2 = gql_wrapper_simple_accessor:compile(query_with_map)
+    local result = gql_query_2:execute(variables_2)
+    print(('RESULT\n%s'):format(yaml.encode(result)))
+end)
diff --git a/test/testdata/array_and_map_testdata.lua b/test/testdata/array_and_map_testdata.lua
index c264b9c..eeccaf1 100755
--- a/test/testdata/array_and_map_testdata.lua
+++ b/test/testdata/array_and_map_testdata.lua
@@ -12,22 +12,22 @@ end
 function array_testdata.get_test_metadata()
 
     local schemas = json.decode([[{
-    "user": {
-        "name": "user",
-        "type": "record",
-        "fields": [
-            { "name": "user_id", "type": "string" },
-            { "name": "favorite_food", "type": {"type": "array", "items": "string"} }
-        ]
+        "user": {
+            "name": "user",
+            "type": "record",
+            "fields": [
+                { "name": "user_id", "type": "string" },
+                { "name": "favorite_food", "type": {"type": "array", "items": "string"} }
+            ]
         }
     }]])
 
     local collections = json.decode([[{
-    "user_collection": {
-        "schema_name": "user",
-        "connections": []
-    }
-}]])
+        "user_collection": {
+            "schema_name": "user",
+            "connections": []
+        }
+    }]])
 
     local service_fields = {
         user = {

From fec3b31b087ae67b4fc0917cca4a3a6187e87327 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Tue, 27 Feb 2018 14:22:55 +0300
Subject: [PATCH 18/26] add test for map with space accessor

---
 ...ray.result => array_and_map_simple.result} |  1 +
 ...test.lua => array_and_map_simple.test.lua} | 40 +++++++++++--------
 test/testdata/array_and_map_testdata.lua      | 18 ++++-----
 3 files changed, 34 insertions(+), 25 deletions(-)
 rename test/local/{avro_array.result => array_and_map_simple.result} (57%)
 rename test/local/{avro_array.test.lua => array_and_map_simple.test.lua} (62%)

diff --git a/test/local/avro_array.result b/test/local/array_and_map_simple.result
similarity index 57%
rename from test/local/avro_array.result
rename to test/local/array_and_map_simple.result
index 6b6cdbb..8274dd3 100644
--- a/test/local/avro_array.result
+++ b/test/local/array_and_map_simple.result
@@ -2,6 +2,7 @@ RESULT
 ---
 user_collection:
 - user_id: user_id_1
+  favorite_holidays: {'december': 'new year', 'march': 'vacation'}
   favorite_food:
   - meat
   - potato
diff --git a/test/local/avro_array.test.lua b/test/local/array_and_map_simple.test.lua
similarity index 62%
rename from test/local/avro_array.test.lua
rename to test/local/array_and_map_simple.test.lua
index 24f25ec..aa16c47 100755
--- a/test/local/avro_array.test.lua
+++ b/test/local/array_and_map_simple.test.lua
@@ -1,12 +1,11 @@
 #!/usr/bin/env tarantool
 
-box.cfg{background = false}
+box.cfg { background = false }
 local fio = require('fio')
 
 -- require in-repo version of graphql/ sources despite current working directory
 package.path = fio.abspath(debug.getinfo(1).source:match("@?(.*/)")
-   :gsub('/./', '/'):gsub('/+$', '')) .. '/../../?.lua' .. ';' ..
-package.path
+    :gsub('/./', '/'):gsub('/+$', '')) .. '/../../?.lua' .. ';' .. package.path
 
 local graphql = require('graphql')
 local testdata = require('test.testdata.array_and_map_testdata')
@@ -27,22 +26,31 @@ local schemas = metadata.schemas
 local collections = metadata.collections
 local service_fields = metadata.service_fields
 local indexes = metadata.indexes
+local utils = require('graphql.utils')
 
 -- build accessor and graphql schemas
 -- ----------------------------------
-
-local accessor = graphql.accessor_space.new({
-    schemas = schemas,
-    collections = collections,
-    service_fields = service_fields,
-    indexes = indexes,
-})
-
-local gql_wrapper = graphql.new({
-    schemas = schemas,
-    collections = collections,
-    accessor = accessor,
-})
+local accessor
+utils.show_trace(
+function()
+    accessor = graphql.accessor_space.new({
+        schemas = schemas,
+        collections = collections,
+        service_fields = service_fields,
+        indexes = indexes,
+    })
+end
+)
+
+local gql_wrapper
+utils.show_trace(function()
+    gql_wrapper = graphql.new({
+        schemas = schemas,
+        collections = collections,
+        accessor = accessor,
+    })
+end
+)
 
 -- run queries
 -- -----------
diff --git a/test/testdata/array_and_map_testdata.lua b/test/testdata/array_and_map_testdata.lua
index eeccaf1..092193a 100755
--- a/test/testdata/array_and_map_testdata.lua
+++ b/test/testdata/array_and_map_testdata.lua
@@ -17,7 +17,8 @@ function array_testdata.get_test_metadata()
             "type": "record",
             "fields": [
                 { "name": "user_id", "type": "string" },
-                { "name": "favorite_food", "type": {"type": "array", "items": "string"} }
+                { "name": "favorite_food", "type": {"type": "array", "items": "string"} },
+                { "name": "favorite_holidays", "type": {"type": "map", "values": "string"} }
             ]
         }
     }]])
@@ -74,9 +75,8 @@ function array_testdata.fill_test_data(shard)
     local shard = shard or box.space
 
     shard.user_collection:replace(
-        { 1827767717, 'user_id_1', { 'meat', 'potato' } })
-    shard.user_collection:replace(
-        { 1827767717, 'user_id_2', { 'fruit' } })
+        { 1827767717, 'user_id_1', { 'meat', 'potato' },
+        { december = 'new year', march = 'vacation'} })
     --@todo add empty array
 end
 
@@ -89,22 +89,22 @@ function array_testdata.run_queries(gql_wrapper)
 
     local results = ''
 
-    local query_1 = [[
-        query user_favorites($user_id: String) {
+    local query_map = [[
+        query user_holidays($user_id: String) {
             user_collection(user_id: $user_id) {
                 user_id
                 favorite_food
+                favorite_holidays
             }
         }
     ]]
 
-    --assert(false, 'err')
     utils.show_trace(function()
         local variables_1 = { user_id = 'user_id_1' }
-        local gql_query_1 = gql_wrapper:compile(query_1)
+        local gql_query_1 = gql_wrapper:compile(query_map)
         local result = gql_query_1:execute(variables_1)
         results = results .. print_and_return(
-            ('RESULT\n%s'):format(yaml.encode(result)))
+        ('RESULT\n%s'):format(yaml.encode(result)))
     end)
 
     return results

From 0423ec45313a52fdadd5cb1c4e786666e560d6f6 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Wed, 28 Feb 2018 13:02:44 +0300
Subject: [PATCH 19/26] add gql support of avro map/array with records as
 items/values

---
 graphql/tarantool_graphql.lua                 | 14 +++----
 test/local/array_and_map_simple.result        | 10 -----
 .../local/array_and_map_space_accessor.result | 14 +++++++
 ... => array_and_map_space_accessor.test.lua} |  0
 test/testdata/array_and_map_testdata.lua      | 37 +++++++++++++++++--
 5 files changed, 53 insertions(+), 22 deletions(-)
 delete mode 100644 test/local/array_and_map_simple.result
 create mode 100644 test/local/array_and_map_space_accessor.result
 rename test/local/{array_and_map_simple.test.lua => array_and_map_space_accessor.test.lua} (100%)

diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index 1b90281..3d422b0 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -398,14 +398,12 @@ gql_type = function(state, avro_schema, collection, collection_name)
     elseif avro_t == 'array' or avro_t == 'array*' then
         assert(avro_schema.items ~= nil,
             'items field must not be nil in array avro schema')
-        assert(type(avro_schema.items) == 'string',
-            'avro_schema.items must be a string, got '
-                .. type(avro_schema.item))
+        assert(type(avro_schema.items) == 'string'
+            or type(avro_schema.items) == 'table',
+            'avro_schema.items must be a string or a table, got '
+                .. type(avro_schema.items))
 
-        local gql_items_type = convert_scalar_type(avro_schema.items)
-
-        assert(gql_items_type, "only scalars are supported as array items for now "
-            .. avro_type(avro_schema.items) .. " is not a scalar")
+        local gql_items_type = gql_type(state, avro_schema.items)
         local gql_array = types.list(gql_items_type)
         return avro_t == 'array' and types.nonNull(gql_array) or gql_array
     elseif avro_t == 'map' or avro_t == 'map*' then
@@ -417,7 +415,7 @@ gql_type = function(state, avro_schema, collection, collection_name)
             'got %s (avro_schema %s)'):format(type(avro_schema.values),
             json.encode(avro_schema)))
 
-        convert_scalar_type(avro_schema.values, {raise = true})
+        gql_type(state, avro_schema.values)
         local gql_map = types_map
         return avro_t == 'map' and types.nonNull(gql_map) or gql_map
     else
diff --git a/test/local/array_and_map_simple.result b/test/local/array_and_map_simple.result
deleted file mode 100644
index 8274dd3..0000000
--- a/test/local/array_and_map_simple.result
+++ /dev/null
@@ -1,10 +0,0 @@
-RESULT
----
-user_collection:
-- user_id: user_id_1
-  favorite_holidays: {'december': 'new year', 'march': 'vacation'}
-  favorite_food:
-  - meat
-  - potato
-...
-
diff --git a/test/local/array_and_map_space_accessor.result b/test/local/array_and_map_space_accessor.result
new file mode 100644
index 0000000..d293bc3
--- /dev/null
+++ b/test/local/array_and_map_space_accessor.result
@@ -0,0 +1,14 @@
+RESULT
+---
+user_collection:
+- favorite_holidays: {'december': 'new year', 'march': 'vacation'}
+  user_id: user_id_1
+  user_balances:
+  - value: 33
+  - value: 44
+  favorite_food:
+  - meat
+  - potato
+  customer_balances: {'salary': {'value': 333}, 'deposit': {'value': 444}}
+...
+
diff --git a/test/local/array_and_map_simple.test.lua b/test/local/array_and_map_space_accessor.test.lua
similarity index 100%
rename from test/local/array_and_map_simple.test.lua
rename to test/local/array_and_map_space_accessor.test.lua
diff --git a/test/testdata/array_and_map_testdata.lua b/test/testdata/array_and_map_testdata.lua
index 092193a..26bc40b 100755
--- a/test/testdata/array_and_map_testdata.lua
+++ b/test/testdata/array_and_map_testdata.lua
@@ -18,7 +18,29 @@ function array_testdata.get_test_metadata()
             "fields": [
                 { "name": "user_id", "type": "string" },
                 { "name": "favorite_food", "type": {"type": "array", "items": "string"} },
-                { "name": "favorite_holidays", "type": {"type": "map", "values": "string"} }
+                { "name": "favorite_holidays", "type": {"type": "map", "values": "string"} },
+                { "name": "user_balances", "type":
+                    {"type": "array", "items":
+                        {   "name": "balance",
+                            "type": "record",
+                            "fields": [{
+                                "name": "value",
+                                "type": "int"
+                            }]
+                        }
+                    }
+                },
+                { "name": "customer_balances", "type":
+                    {"type": "map", "values":
+                        {   "name": "another_balance",
+                            "type": "record",
+                            "fields": [{
+                                "name": "value",
+                                "type": "int"
+                            }]
+                        }
+                    }
+                }
             ]
         }
     }]])
@@ -76,7 +98,10 @@ function array_testdata.fill_test_data(shard)
 
     shard.user_collection:replace(
         { 1827767717, 'user_id_1', { 'meat', 'potato' },
-        { december = 'new year', march = 'vacation'} })
+        { december = 'new year', march = 'vacation' },
+          { { 33 }, { 44 } },
+          { salary = {333}, deposit = { 444}}
+        })
     --@todo add empty array
 end
 
@@ -89,19 +114,23 @@ function array_testdata.run_queries(gql_wrapper)
 
     local results = ''
 
-    local query_map = [[
+    local query = [[
         query user_holidays($user_id: String) {
             user_collection(user_id: $user_id) {
                 user_id
                 favorite_food
                 favorite_holidays
+                user_balances {
+                    value
+                }
+                customer_balances
             }
         }
     ]]
 
     utils.show_trace(function()
         local variables_1 = { user_id = 'user_id_1' }
-        local gql_query_1 = gql_wrapper:compile(query_map)
+        local gql_query_1 = gql_wrapper:compile(query)
         local result = gql_query_1:execute(variables_1)
         results = results .. print_and_return(
         ('RESULT\n%s'):format(yaml.encode(result)))

From a936771930f7b6ba014af31468873800e88f290f Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Wed, 28 Feb 2018 14:36:58 +0300
Subject: [PATCH 20/26] style/readability fixes after review

---
 graphql/core/execute.lua                 | 81 +++++++++++++++++++++++-
 graphql/tarantool_graphql.lua            | 39 ++++++------
 test/local/simple_avro_array.test.lua    |  9 ++-
 test/testdata/array_and_map_testdata.lua |  8 +--
 4 files changed, 106 insertions(+), 31 deletions(-)

diff --git a/graphql/core/execute.lua b/graphql/core/execute.lua
index 181b0c9..e740100 100644
--- a/graphql/core/execute.lua
+++ b/graphql/core/execute.lua
@@ -79,6 +79,13 @@ local function mergeSelectionSets(fields)
 end
 
 local function defaultResolver(object, arguments, info)
+  --print('print from default resolver in execute 82 ')
+  --print(object)
+  --require('pl.pretty').dump(object)
+  --require('pl.pretty').dump(object)
+  --print('print from default resolver in 86')
+  --require('pl.pretty').dump(info.fieldASTs[1].name.value)
+  --require('pl.pretty').dump(object[info.fieldASTs[1].name.value])
   return object[info.fieldASTs[1].name.value]
 end
 
@@ -145,6 +152,25 @@ end
 
 local evaluateSelections
 
+--- check if given object is flat and have only scalars
+local function is_simple_object(object)
+  assert(type(object) == 'table', 'object type must be table')
+
+  for _, v in pairs(object) do
+    if type(v) == 'table' or type(v) == 'function' then
+      return false
+    end
+  end
+
+  for _, v in ipairs(object) do
+    if type(v) == 'table' or type(v) == 'function' then
+      return false
+    end
+  end
+
+  return true
+end
+
 local function completeValue(fieldType, result, subSelections, context)
   local fieldTypeName = fieldType.__type
 
@@ -163,6 +189,7 @@ local function completeValue(fieldType, result, subSelections, context)
     return nil
   end
 
+
   if fieldTypeName == 'List' then
     local innerType = fieldType.ofType
 
@@ -172,7 +199,21 @@ local function completeValue(fieldType, result, subSelections, context)
 
     local values = {}
     for i, value in ipairs(result) do
+      --print('print from List section in completeValue() 182 with i == ' .. i)
+      --print('INNER TYPE')
+      --require('pl.pretty').dump(innerType)
+      --print('VALUE')
+      --require('pl.pretty').dump(value)
+      --
+      --print("is simple object?")
+      --print(is_simple_object(value))
+
+      --values[i] = is_simple_object(value) and value or
+      --  completeValue(innerType, value, subSelections, context)
       values[i] = completeValue(innerType, value, subSelections, context)
+      --print('result after completeValue()')
+      --require('pl.pretty').dump(value[i])
+
     end
 
     return next(values) and values or context.schema.__emptyList
@@ -183,6 +224,9 @@ local function completeValue(fieldType, result, subSelections, context)
   end
 
   if fieldTypeName == 'Object' then
+    -- можно добавить условие, что если объект простой
+    -- и вложенностей нет
+    -- то вернуть его как есть и не делать evaluateSelections
     local fields = evaluateSelections(fieldType, result, subSelections, context)
     return next(fields) and fields or context.schema.__emptyObject
   elseif fieldTypeName == 'Interface' or fieldTypeName == 'Union' then
@@ -194,10 +238,17 @@ local function completeValue(fieldType, result, subSelections, context)
 end
 
 local function getFieldEntry(objectType, object, fields, context)
+
+  --print('print from 242 execute lua')
+
   local firstField = fields[1]
   local fieldName = firstField.name.value
   local responseKey = getFieldResponseKey(firstField)
   local fieldType = introspection.fieldMap[fieldName] or objectType.fields[fieldName]
+  --
+  --require('pl.pretty').dump(fieldName)
+  --require('pl.pretty').dump(fieldType)
+
 
   if fieldType == nil then
     return nil
@@ -227,25 +278,53 @@ local function getFieldEntry(objectType, object, fields, context)
 
   local resolvedObject = (fieldType.resolve or defaultResolver)(object, arguments, info)
   local subSelections = mergeSelectionSets(fields)
+  --print('print from 258 in execute')
+  --require('pl.pretty').dump(resolvedObject)
+
+
+  --print('resolvedObject')
+  --require('pl.pretty').dump(objectType)
+
+  local res = completeValue(fieldType.kind, resolvedObject, subSelections, context)
+  --print('complete value result from 256 in execute.lua')
+  --require('pl.pretty').dump(res)
 
-  return completeValue(fieldType.kind, resolvedObject, subSelections, context)
+  return res
 end
 
 evaluateSelections = function(objectType, object, selections, context)
   local groupedFieldSet = collectFields(objectType, selections, {}, {}, context)
 
+  --print('print from 298, groupedFieldSet')
+  --require('pl.pretty').dump(groupedFieldSet)
+  --print('OBJECT')
+  --require('pl.pretty').dump(object)
+  --print('OBJECT TYPE')
+  --require('pl.pretty').dump(objectType)
+  --print('SELECTIONS')
+  --require('pl.pretty').dump(selections)
+
+
+
+
   return util.map(groupedFieldSet, function(fields)
     return getFieldEntry(objectType, object, fields, context)
   end)
 end
 
 return function(schema, tree, rootValue, variables, operationName)
+
+
   local context = buildContext(schema, tree, rootValue, variables, operationName)
   local rootType = schema[context.operation.operation]
 
+
+
   if not rootType then
     error('Unsupported operation "' .. context.operation.operation .. '"')
   end
 
+
+
   return evaluateSelections(rootType, rootValue, context.operation.selectionSet.selections, context)
 end
diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index 3d422b0..6cb7469 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -102,7 +102,7 @@ local function convert_scalar_type(avro_schema, opts)
         type(opts))
     local raise = opts.raise or false
     assert(type(raise) == 'boolean', 'opts.raise must be boolean, got ' ..
-        type(opts.raise))
+        type(raise))
 
     local avro_t = avro_type(avro_schema)
     if avro_t == 'int' then
@@ -121,7 +121,7 @@ local function convert_scalar_type(avro_schema, opts)
 
     if raise then
         error('unrecognized avro-schema scalar type: ' ..
-        json.encode(avro_schema))
+            json.encode(avro_schema))
     end
 
     return nil
@@ -132,7 +132,7 @@ end
 --- An error will be raised if avro_schema type is 'record'
 --- and its' fields are not scalar type because currently
 --- triple nesting level (record with record as a field - ok,
---- record with record wich has inside another level - not ok)
+--- record with record which has inside another level - not ok).
 local function gql_argument_type(state, avro_schema)
     assert(type(state) == 'table',
         'state must be a table, got ' .. type(state))
@@ -174,13 +174,13 @@ local function gql_argument_type(state, avro_schema)
     else
         local res = convert_scalar_type(avro_schema, {raise = false})
         if res == nil then
-            error('unrecognized avro-schema type: ' .. json.encode(avro_schema))
+            error('unrecognized avro-schema type: ' ..
+                json.encode(avro_schema))
         end
         return res
     end
 end
 
-
 -- Convert list of fields in the avro-schema format to list of GraphQL types
 -- with intention to use it as GraphQL arguments later.
 -- It uses the @{gql_argument_type} function to convert each field, then skips
@@ -207,15 +207,13 @@ local function convert_record_fields_to_args(state, fields)
     return args
 end
 
---- Recursively convert each field of an avro-schema to a graphql type and
+--- Convert each field of an avro-schema to a graphql type and
 --- corresponding argument for an upper graphql type.
 ---
 --- @tparam table state for read state.accessor and previously filled
 --- state.types
 --- @tparam table fields fields part from an avro-schema
---- @tparam table opts include is_for_args flag to specify
---- case when the function is used to collect arguments
-local function convert_record_fields(state, fields, opts)
+local function convert_record_fields(state, fields)
     local res = {}
     local object_args = {}
 
@@ -255,7 +253,7 @@ end
 ---    instead of the avro-schema name.
 ---
 --- XXX As it is not clear now what to do with complex types inside arrays
----(just pass to results or allow to use filters), only scalar arrays
+--- (just pass to results or allow to use filters), only scalar arrays
 --- is allowed for now.
 gql_type = function(state, avro_schema, collection, collection_name)
     assert(type(state) == 'table',
@@ -400,8 +398,8 @@ gql_type = function(state, avro_schema, collection, collection_name)
             'items field must not be nil in array avro schema')
         assert(type(avro_schema.items) == 'string'
             or type(avro_schema.items) == 'table',
-            'avro_schema.items must be a string or a table, got '
-                .. type(avro_schema.items))
+            'avro_schema.items must be a string or a table, got ' ..
+            type(avro_schema.items))
 
         local gql_items_type = gql_type(state, avro_schema.items)
         local gql_array = types.list(gql_items_type)
@@ -421,7 +419,8 @@ gql_type = function(state, avro_schema, collection, collection_name)
     else
         local res = convert_scalar_type(avro_schema, {raise = false})
         if res == nil then
-            error('unrecognized avro-schema type: ' .. json.encode(avro_schema))
+            error('unrecognized avro-schema type: ' ..
+                json.encode(avro_schema))
         end
         return res
     end
@@ -460,10 +459,11 @@ local function parse_cfg(cfg)
             'the schema itself: "%s" vs "%s"'):format(collection.schema_name,
             schema.name))
 
-        -- recursively converts all avro types into gql types in the given schema
+        -- recursively converts all avro types into GraphQL types in the given
+        -- schema
         assert(schema.type == 'record',
-            'top-level schema must have record avro type, not '
-                .. schema.type)
+            'top-level schema must have record avro type, got ' ..
+            tostring(schema.type))
         state.types[collection_name] = gql_type(state, schema, collection,
             collection_name)
 
@@ -516,7 +516,7 @@ end
 
 --- The function checks that one and only one GraphQL operation
 --- (query/mutation/subscription) is defined in the AST and it's type
---- is 'query' as mutations and subscriptions are not supported yet
+--- is 'query' as mutations and subscriptions are not supported yet.
 local function assert_gql_query_ast(func_name, ast)
     assert(#ast.definitions == 1,
         func_name .. ': expected an one query')
@@ -549,10 +549,11 @@ end
 
 --- The function parses a query string, validate the resulting query
 --- against the GraphQL schema and provides an object with the function to
---- execute the query with specific variables values
+--- execute the query with specific variables values.
+---
 --- @tparam table state current state of graphql, including
 --- schemas, collections and accessor
---- @tparam string query raw query string
+--- @tparam string query query string
 local function gql_compile(state, query)
     assert(type(state) == 'table' and type(query) == 'string',
         'use :validate(...) instead of .validate(...)')
diff --git a/test/local/simple_avro_array.test.lua b/test/local/simple_avro_array.test.lua
index 257cc8c..5657b46 100755
--- a/test/local/simple_avro_array.test.lua
+++ b/test/local/simple_avro_array.test.lua
@@ -4,8 +4,7 @@ local fio = require('fio')
 
  --require in-repo version of graphql/ sources despite current working directory
 package.path = fio.abspath(debug.getinfo(1).source:match("@?(.*/)")
-                                :gsub('/./', '/'):gsub('/+$', '')) .. '/../../?.lua' .. ';' ..
-        package.path
+    :gsub('/./', '/'):gsub('/+$', '')) .. '/../../?.lua' .. ';' .. package.path
 
 
 local json = require('json')
@@ -72,11 +71,11 @@ local simple_accessor = setmetatable({}, {
 })
 
 local gql_wrapper_simple_accessor = graphql.new({
--- class_name:class mapping
+    -- class_name:class mapping
     schemas = schemas,
--- collection_{schema_name=..., connections=...} mapping
+    -- collection_{schema_name=..., connections=...} mapping
     collections = collections,
--- :select() and :list_args() provider
+    -- :select() and :list_args() provider
     accessor = simple_accessor,
 })
 
diff --git a/test/testdata/array_and_map_testdata.lua b/test/testdata/array_and_map_testdata.lua
index 26bc40b..ae280b1 100755
--- a/test/testdata/array_and_map_testdata.lua
+++ b/test/testdata/array_and_map_testdata.lua
@@ -10,7 +10,6 @@ local function print_and_return(...)
 end
 
 function array_testdata.get_test_metadata()
-
     local schemas = json.decode([[{
         "user": {
             "name": "user",
@@ -86,9 +85,7 @@ function array_testdata.init_spaces()
     box.once('test_space_init_spaces', function()
         box.schema.create_space('user_collection')
         box.space.user_collection:create_index('user_id_index',
-            { type = 'tree', unique = true, parts = {
-                U_USER_ID_FN, 'string'
-            } }
+            { type = 'tree', unique = true, parts = { U_USER_ID_FN, 'string' }}
         )
     end)
 end
@@ -100,7 +97,7 @@ function array_testdata.fill_test_data(shard)
         { 1827767717, 'user_id_1', { 'meat', 'potato' },
         { december = 'new year', march = 'vacation' },
           { { 33 }, { 44 } },
-          { salary = {333}, deposit = { 444}}
+          { salary = { 333 }, deposit = { 444 } }
         })
     --@todo add empty array
 end
@@ -111,7 +108,6 @@ function array_testdata.drop_spaces()
 end
 
 function array_testdata.run_queries(gql_wrapper)
-
     local results = ''
 
     local query = [[

From c8abf95ab733349777043b5a12de7c551c4ff7c2 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Wed, 28 Feb 2018 14:39:16 +0300
Subject: [PATCH 21/26] remove executable bit

---
 graphql/utils.lua | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 mode change 100755 => 100644 graphql/utils.lua

diff --git a/graphql/utils.lua b/graphql/utils.lua
old mode 100755
new mode 100644

From 951e7eab049cb90ea391b9edf056c17803969e90 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Wed, 28 Feb 2018 16:41:02 +0300
Subject: [PATCH 22/26] add info about Map

---
 README.md | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/README.md b/README.md
index d273bc3..c001bbb 100644
--- a/README.md
+++ b/README.md
@@ -47,6 +47,42 @@ GraphQL queries on data from the local Tarantool's storage called spaces.
 It is planned to implement another data accessor that allows to fetch objects
 sharded using tarantool/shard module.
 
+### Notes on types
+
+User should distinguish between Object and Map types. Both of them consists of
+keys and values but there are some important differences. 
+
+While Object is a GraphQL
+built-in type, Map is a scalar-based type. In case of Object-based type 
+all key-value pairs are set during type definition and values may have different 
+arbitrary types.
+
+In contrast, all values of Map-based type must have the same
+type and specific key-value pairs are not set during type definition.
+
+Map-based types should be queried as a scalar type, not as a object type 
+(because map's keys are not part of the schema)
+
+
+This works
+```
+{
+    …
+    map_based_type
+    …
+}
+```
+
+This doesn't work
+```
+{
+    …
+    map_based_type {
+        key_1
+    }
+    …
+}
+```
 ## Run tests
 
 ```

From 91bd8bf95d242ba07bd65c6dc06c77872736293c Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Wed, 28 Feb 2018 16:42:10 +0300
Subject: [PATCH 23/26] typo fix

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index c001bbb..332f8a5 100644
--- a/README.md
+++ b/README.md
@@ -60,7 +60,7 @@ arbitrary types.
 In contrast, all values of Map-based type must have the same
 type and specific key-value pairs are not set during type definition.
 
-Map-based types should be queried as a scalar type, not as a object type 
+Map-based types should be queried as a scalar type, not as an object type 
 (because map's keys are not part of the schema)
 
 

From d9a762383272da1f739811b7058b8f079dbc2206 Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Wed, 28 Feb 2018 19:42:05 +0300
Subject: [PATCH 24/26] remove whitespaces at the end of lines

---
 README.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 332f8a5..f124801 100644
--- a/README.md
+++ b/README.md
@@ -50,17 +50,17 @@ sharded using tarantool/shard module.
 ### Notes on types
 
 User should distinguish between Object and Map types. Both of them consists of
-keys and values but there are some important differences. 
+keys and values but there are some important differences.
 
 While Object is a GraphQL
-built-in type, Map is a scalar-based type. In case of Object-based type 
+built-in type, Map is a scalar-based type. In case of Object-based type
 all key-value pairs are set during type definition and values may have different 
 arbitrary types.
 
 In contrast, all values of Map-based type must have the same
 type and specific key-value pairs are not set during type definition.
 
-Map-based types should be queried as a scalar type, not as an object type 
+Map-based types should be queried as a scalar type, not as an object type
 (because map's keys are not part of the schema)
 
 

From 1f2583a84779534ff09e16dd74a0d1af1984948a Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Wed, 28 Feb 2018 19:53:19 +0300
Subject: [PATCH 25/26] remove all debug prints

---
 graphql/core/execute.lua | 81 +---------------------------------------
 1 file changed, 1 insertion(+), 80 deletions(-)

diff --git a/graphql/core/execute.lua b/graphql/core/execute.lua
index 5ed6714..92d5070 100644
--- a/graphql/core/execute.lua
+++ b/graphql/core/execute.lua
@@ -79,13 +79,6 @@ local function mergeSelectionSets(fields)
 end
 
 local function defaultResolver(object, arguments, info)
-  --print('print from default resolver in execute 82 ')
-  --print(object)
-  --require('pl.pretty').dump(object)
-  --require('pl.pretty').dump(object)
-  --print('print from default resolver in 86')
-  --require('pl.pretty').dump(info.fieldASTs[1].name.value)
-  --require('pl.pretty').dump(object[info.fieldASTs[1].name.value])
   return object[info.fieldASTs[1].name.value]
 end
 
@@ -155,25 +148,6 @@ end
 
 local evaluateSelections
 
---- check if given object is flat and have only scalars
-local function is_simple_object(object)
-  assert(type(object) == 'table', 'object type must be table')
-
-  for _, v in pairs(object) do
-    if type(v) == 'table' or type(v) == 'function' then
-      return false
-    end
-  end
-
-  for _, v in ipairs(object) do
-    if type(v) == 'table' or type(v) == 'function' then
-      return false
-    end
-  end
-
-  return true
-end
-
 local function completeValue(fieldType, result, subSelections, context)
   local fieldTypeName = fieldType.__type
 
@@ -192,7 +166,6 @@ local function completeValue(fieldType, result, subSelections, context)
     return nil
   end
 
-
   if fieldTypeName == 'List' then
     local innerType = fieldType.ofType
 
@@ -202,21 +175,7 @@ local function completeValue(fieldType, result, subSelections, context)
 
     local values = {}
     for i, value in ipairs(result) do
-      --print('print from List section in completeValue() 182 with i == ' .. i)
-      --print('INNER TYPE')
-      --require('pl.pretty').dump(innerType)
-      --print('VALUE')
-      --require('pl.pretty').dump(value)
-      --
-      --print("is simple object?")
-      --print(is_simple_object(value))
-
-      --values[i] = is_simple_object(value) and value or
-      --  completeValue(innerType, value, subSelections, context)
       values[i] = completeValue(innerType, value, subSelections, context)
-      --print('result after completeValue()')
-      --require('pl.pretty').dump(value[i])
-
     end
 
     return next(values) and values or context.schema.__emptyList
@@ -227,9 +186,6 @@ local function completeValue(fieldType, result, subSelections, context)
   end
 
   if fieldTypeName == 'Object' then
-    -- можно добавить условие, что если объект простой
-    -- и вложенностей нет
-    -- то вернуть его как есть и не делать evaluateSelections
     local fields = evaluateSelections(fieldType, result, subSelections, context)
     return next(fields) and fields or context.schema.__emptyObject
   elseif fieldTypeName == 'Interface' or fieldTypeName == 'Union' then
@@ -241,17 +197,10 @@ local function completeValue(fieldType, result, subSelections, context)
 end
 
 local function getFieldEntry(objectType, object, fields, context)
-
-  --print('print from 242 execute lua')
-
   local firstField = fields[1]
   local fieldName = firstField.name.value
   local responseKey = getFieldResponseKey(firstField)
   local fieldType = introspection.fieldMap[fieldName] or objectType.fields[fieldName]
-  --
-  --require('pl.pretty').dump(fieldName)
-  --require('pl.pretty').dump(fieldType)
-
 
   if fieldType == nil then
     return nil
@@ -282,53 +231,25 @@ local function getFieldEntry(objectType, object, fields, context)
 
   local resolvedObject = (fieldType.resolve or defaultResolver)(object, arguments, info)
   local subSelections = mergeSelectionSets(fields)
-  --print('print from 258 in execute')
-  --require('pl.pretty').dump(resolvedObject)
-
-
-  --print('resolvedObject')
-  --require('pl.pretty').dump(objectType)
-
-  local res = completeValue(fieldType.kind, resolvedObject, subSelections, context)
-  --print('complete value result from 256 in execute.lua')
-  --require('pl.pretty').dump(res)
 
-  return res
+  return completeValue(fieldType.kind, resolvedObject, subSelections, context)
 end
 
 evaluateSelections = function(objectType, object, selections, context)
   local groupedFieldSet = collectFields(objectType, selections, {}, {}, context)
 
-  --print('print from 298, groupedFieldSet')
-  --require('pl.pretty').dump(groupedFieldSet)
-  --print('OBJECT')
-  --require('pl.pretty').dump(object)
-  --print('OBJECT TYPE')
-  --require('pl.pretty').dump(objectType)
-  --print('SELECTIONS')
-  --require('pl.pretty').dump(selections)
-
-
-
-
   return util.map(groupedFieldSet, function(fields)
     return getFieldEntry(objectType, object, fields, context)
   end)
 end
 
 return function(schema, tree, rootValue, variables, operationName)
-
-
   local context = buildContext(schema, tree, rootValue, variables, operationName)
   local rootType = schema[context.operation.operation]
 
-
-
   if not rootType then
     error('Unsupported operation "' .. context.operation.operation .. '"')
   end
 
-
-
   return evaluateSelections(rootType, rootValue, context.operation.selectionSet.selections, context)
 end

From e406a314d7d614d4c6d54986bedc7831ac89310f Mon Sep 17 00:00:00 2001
From: SudoBobo <ivan.koptelov@phystech.edu>
Date: Wed, 28 Feb 2018 20:08:56 +0300
Subject: [PATCH 26/26] make Map and Object explanation more specific

---
 README.md | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 270acbb..209047d 100644
--- a/README.md
+++ b/README.md
@@ -54,14 +54,15 @@ keys and values but there are some important differences.
 
 While Object is a GraphQL
 built-in type, Map is a scalar-based type. In case of Object-based type
-all key-value pairs are set during type definition and values may have different 
-arbitrary types.
+all key-value pairs are set during type definition and values may have
+different types (as defined in the schema).
 
-In contrast, all values of Map-based type must have the same
-type and specific key-value pairs are not set during type definition.
+In contrast, set of valid Map keys is not defined in the schema, any key-value
+pair is valid despite name of the key while value has schema-determined type
+(which is the same among all values in the map).
 
 Map-based types should be queried as a scalar type, not as an object type
-(because map's keys are not part of the schema)
+(because map's keys are not part of the schema).
 
 
 This works