def simplify_list(pattern): if type(pattern) == ebnf_semantic.Concatenation: terms = [term for term in pattern.terms if term != None] if len(terms) == 0: return None if len(terms) == 1: return terms[0] return ebnf_semantic.Concatenation(terms) elif type(pattern) == ebnf_semantic.Alternation: clauses = sorted(list(set([clause for clause in pattern.clauses if clause != None]))) if len(clauses) == 0: return None if len(clauses) == 1: result = clauses[0] else: result = ebnf_semantic.Alternation(clauses) if None in pattern.clauses: result = ebnf_semantic.Optional(result) return result return pattern
def build_state_node_for_optional(pattern, cache):
subnode = build_state_node(pattern.rhs, cache)
transitions = {symbol: next_pattern for symbol, next_pattern in subnode.transitions.items()}
if None in transitions and transitions[None] != None:
transitions[None] = ebnf_semantic.Optional(transitions[None])
else:
transitions[None] = None
node = StateNode()
node.transitions = transitions
return node
def simplify_alternation_with_repetition(pattern): clauses = [simplify_list(ebnf_semantic.Concatenation([clause.rhs, clause])) if type(clause) == ebnf_semantic.Repetition else clause for clause in pattern.clauses] return ebnf_semantic.Optional(simplify_list(ebnf_semantic.Alternation(clauses)))
def simplify_alternation_with_optional(pattern): clauses = [clause.rhs if type(clause) == ebnf_semantic.Optional else clause for clause in pattern.clauses] return ebnf_semantic.Optional(simplify_list(ebnf_semantic.Alternation(clauses)))
def simplify_concatenation_to_repetition(term1, term2): term1 = ebnf_semantic.Optional(simplify_list(ebnf_semantic.Concatenation([term1.rhs, term1]))) return simplify_concatenation_to_optional(term1, term2)
def merge_maps(prefix_map1, prefix_map2, ast_info, cache):
if ebnf_semantic.Identifier in map(
type, prefix_map1.keys()) and ebnf_semantic.Identifier in map(
type, prefix_map2.keys()):
identkey1 = None
identkey2 = None
for c in prefix_map1.keys():
if type(c) == ebnf_semantic.Identifier:
identkey1 = c
break
for c in prefix_map2.keys():
if type(c) == ebnf_semantic.Identifier:
identkey2 = c
break
if identkey1 != identkey2:
expanded_map1 = expand_for_merge(prefix_map1, ast_info, cache)
expanded_map2 = expand_for_merge(prefix_map2, ast_info, cache)
return merge_maps(expanded_map1, expanded_map2, ast_info, cache)
elif PartialIdentifier in map(
type, prefix_map1.keys()) and PartialIdentifier in map(
type, prefix_map2.keys()):
identkey1 = None
identkey2 = None
for c in prefix_map1.keys():
if type(c) == PartialIdentifier:
identkey1 = c
break
for c in prefix_map2.keys():
if type(c) == PartialIdentifier:
identkey2 = c
break
if is_finished_partial(identkey1) and is_finished_partial(identkey2):
# ambiguous. which to return?
return prefix_map1
if identkey1 != identkey2:
expanded_map1 = expand_for_merge(prefix_map1, ast_info, cache)
expanded_map2 = expand_for_merge(prefix_map2, ast_info, cache)
return merge_maps(expanded_map1, expanded_map2, ast_info, cache)
elif ebnf_semantic.Identifier in map(
type, prefix_map1.keys()) or PartialIdentifier in map(
type, prefix_map1.keys()):
expanded_map1 = expand_for_merge(prefix_map1, ast_info, cache)
return merge_maps(expanded_map1, prefix_map2, ast_info, cache)
elif ebnf_semantic.Identifier in map(
type, prefix_map2.keys()) or PartialIdentifier in map(
type, prefix_map2.keys()):
expanded_map2 = expand_for_merge(prefix_map2, ast_info, cache)
return merge_maps(prefix_map1, expanded_map2, ast_info, cache)
else:
new_map = {}
for c in prefix_map1:
if c in prefix_map2:
subpattern1 = prefix_map1[c]
subpattern2 = prefix_map2[c]
if subpattern1 == None:
if subpattern2 == None:
new_map[c] = None
else:
new_map[c] = ebnf_semantic.Optional(
subpattern2, subpattern2.offset)
else:
if subpattern2 == None:
new_map[c] = ebnf_semantic.Optional(
subpattern1, subpattern1.offset)
else:
if type(subpattern1) == ebnf_semantic.Alternation:
if type(subpattern2) == ebnf_semantic.Alternation:
new_map[c] = ebnf_semantic.Alternation(
list(subpattern1.clauses) +
list(subpattern2.clauses),
subpattern1.clauses[0].offset)
else:
new_map[c] = ebnf_semantic.Alternation(
list(subpattern1.clauses) + [subpattern2],
subpattern1.clauses[0].offset)
else:
if type(subpattern2) == ebnf_semantic.Alternation:
new_map[c] = ebnf_semantic.Alternation(
[subpattern1] + list(subpattern2.clauses),
subpattern1.offset)
else:
new_map[c] = ebnf_semantic.Alternation(
[subpattern1, subpattern2],
subpattern1.offset)
else:
new_map[c] = prefix_map1[c]
for c in prefix_map2:
if c not in prefix_map1:
new_map[c] = prefix_map2[c]
return new_map