Support (?i) in regexps

Related to #79.

Author: Totktonada

README.md

@@ -101,13 +101,13 @@ make test
   * tarantool,
   * lulpeg,
   * >=tarantool/avro-schema-2.0-71-gfea0ead,
-  * >=tarantool/shard-1.1-91-gfa88bf8 (optional),
-  * lrexlib-pcre (optional).
+  * >=tarantool/shard-1.1-91-gfa88bf8 (but < 2.0) (optional),
+  * lrexlib-pcre2 or lrexlib-pcre (optional).
 * For test (additionally to 'for use'):
   * python 2.7,
   * virtualenv,
   * luacheck,
-  * >=tarantool/shard-1.1-92-gec1a27e.
+  * >=tarantool/shard-1.1-92-gec1a27e (but < 2.0).
 * For building apidoc (additionally to 'for use'):
   * ldoc.
 

graphql/accessor_general.lua

@@ -9,7 +9,11 @@ local json = require('json')
 local avro_schema = require('avro_schema')
 local utils = require('graphql.utils')
 local clock = require('clock')
-local rex = utils.optional_require('rex_pcre')
+local rex, is_pcre2 = utils.optional_require('rex_pcre2'), true
+if rex == nil then
+    -- fallback to libpcre
+    rex, is_pcre2 = utils.optional_require('rex_pcre'), false
+end
 
 -- XXX: consider using [1] when it will be mature enough;
 -- look into [2] for the status.
@@ -777,8 +781,17 @@ local function match_using_re(obj, pcre)
         assert(rex ~= nil, 'we should not pass over :compile() ' ..
             'with a query contains PCRE matching when there are '..
             'no lrexlib-pcre (rex_pcre) module present')
+        -- emulate behaviour of (?i) on libpcre (libpcre2 supports it)
+        local cfg
+        if not is_pcre2 then
+            local cnt
+            re, cnt = re:gsub('^%(%?i%)', '')
+            if cnt > 0 then
+                cfg = 'i'
+            end
+        end
         -- XXX: compile re once
-        local re = rex.new(re)
+        local re = rex.new(re, cfg)
         if not re:match(obj[field_name]) then
             return false
         end

test/local/space_pcre.result

@@ -12,7 +12,7 @@ QUERY
 VARIABLES
 ---
 middle_name_re: ich$
-first_name_re: ^I
+first_name_re: (?i)^i
 ...
 
 RESULT

test/local/space_pcre.test.lua

@@ -83,7 +83,7 @@ local function run_queries(gql_wrapper)
 
     utils.show_trace(function()
         local variables_1_1 = {
-            first_name_re = '^I',
+            first_name_re = '(?i)^i',
             middle_name_re = 'ich$',
         }
         local result = gql_query_1:execute(variables_1_1)