forward chaining algorithm complete

Author: KarimAly12

propositional_logic_inference_algorithms/forward_chaining

@@ -3,7 +3,11 @@ import re
 
 def find_symbols_in_kb(knowledge_base: list[str]) -> dict:
     '''
+    Find all unique symbols in the Knowledge_base
+    :param knowledge_base: a list of string of definite clauses
+    :returns: a dictionary with symbols as the keys their values are False
     '''
+
     inferred = {}
 
     for i in range(len(knowledge_base)):
@@ -18,6 +22,9 @@ def find_symbols_in_kb(knowledge_base: list[str]) -> dict:
 def number_of_symbols_in_premise(knowledge_base: list[str]) -> dict:
 
     '''
+    Count the number of prposiotion symbols in each premise of KB clause
+    :param knowledge_base: a list of string of definite clauses
+    :returns: a dictionary with key as the premise of KB clause and vlaue of count of symbols in the premise
     '''
 
     count = {}
@@ -32,9 +39,13 @@ def number_of_symbols_in_premise(knowledge_base: list[str]) -> dict:
 
 
 def get_known_facts(knowledge_base: list[str]) -> list[str]:
-
     '''
+    Get the known facts in KB
+    :param knowledge_base: a list of string of definite clauses
+    :returns: list of facts
+
     '''
+
     facts = []
     for clause in knowledge_base:
         if len(clause) == 1:
@@ -45,7 +56,17 @@ def get_known_facts(knowledge_base: list[str]) -> list[str]:
 
 
 
-def forward_chianing(knowledge_base: list[str], query:str) -> bool:
+def forward_chaining(knowledge_base: list[str], query:str) -> bool:
+    ''' Forward chaining on Knowledge Base(KB) of definite clauses
+    :param knowledge_base: a list of string of definite clauses
+    :param query: a single proposition sysmbol that you are checking if it is entailed by the  KB
+    :returns: If the query entailed by the KB or not?
+    >>> forward_chaining([ "P => Q", "L & M => P", "B&L=> M", "A&P=>L", "A&B=>L", "A", "B" ], "Q")
+    True
+    >>> forward_chaining([ "P => Q", "L & M => P", "B&L=> M", "A&P=>L", "A&B=>L", "A", "B" ], "C")
+    False
+
+    '''
 
     count = number_of_symbols_in_premise(knowledge_base)
     inferred = find_symbols_in_kb(knowledge_base)
@@ -68,9 +89,35 @@ def forward_chianing(knowledge_base: list[str], query:str) -> bool:
 
 
 
+
+KB = [ 
+        "P => Q", 
+        "L & M => P", 
+        "B&L=> M",
+        "A&P=>L", 
+        "A&B=>L", 
+        "A", 
+        "B" ]
+
+'''
+1)- KB must be written in horn form.
+2)- It must be written as an implcaion whoose 
+its premise(head) must be conjuction of positive literals and its conclusion(body)
+3)- It must contains facts about the world which are written as a single proposition symbol
+'''
+
+QUERY = "Q"
+
+'''
+Query is a signe proposition symbol that you check if it is entailed by the KB
+'''
+
 if __name__ == "__main__":
+
 
-    kb = ["p => q", "q => r", "r => p", "s => t", "u => v", "v => w", "w => u", "a", "b", "c" , "w" , "u&q=>r", "q"]
+    import doctest
 
-    result = forward_chianing(kb, "t")
+    doctest.testmod(verbose=True)
+   
+    result = forward_chaining(KB, QUERY)
     print(result)