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arpeggio-gm
Commit 2d460242 authored by Igor Dejanovic's avatar Igor Dejanovic
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Fixing peg language

parent 8609d13a
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Showing with 65 additions and 85 deletions
arpeggio/peg.py
View file @ 2d460242
......@@ -16,6 +16,17 @@ from arpeggio.export import PMDOTExporter, PTDOTExporter
__all__ = ['ParserPEG']
# PEG syntax rules
def peggrammar(): return OneOrMore(rule), EOF
def rule(): return rule_name, LEFT_ARROW, ordered_choice, ";"
def ordered_choice(): return sequence, ZeroOrMore(SLASH, sequence)
def sequence(): return OneOrMore(prefix)
def prefix(): return Optional([AND,NOT]), sufix
def sufix(): return expression, Optional([QUESTION, STAR, PLUS])
def expression(): return [regex, rule_crossref,
(OPEN, ordered_choice, CLOSE),
str_match]
# PEG Lexical rules
def LEFT_ARROW(): return "<-"
def SLASH(): return "/"
......@@ -33,84 +44,73 @@ def rule_crossref(): return rule_name
def str_match(): return _(r'(\'(\\\'|[^\'])*\')|("[^"]*")')
def comment(): return "//", _(".*\n")
# PEG syntax rules
def peggrammar(): return OneOrMore(rule), EOF
def rule(): return rule_name, LEFT_ARROW, ordered_choice, ";"
def ordered_choice(): return sequence, ZeroOrMore(SLASH, sequence)
def sequence(): return OneOrMore(prefix)
def prefix(): return Optional([AND,NOT]), sufix
def sufix(): return expression, Optional([QUESTION, STAR, PLUS])
def expression(): return [regex, rule_crossref,
(OPEN, ordered_choice, CLOSE),
str_match]
# ------------------------------------------------------------------
# PEG Semantic Actions
class PEGSemanticAction(SemanticAction):
def _resolve(self, parser, rule_name):
class SemGrammar(SemanticAction):
if rule_name in parser.peg_rules:
resolved_rule = parser.peg_rules[rule_name]
if type(resolved_rule) is CrossRef:
resolved_rule = self._resolve(parser, resolved_rule.rule_name)
def first_pass(self, parser, node, children):
return parser.peg_rules[parser.root_rule_name]
if parser.debug:
print("Resolving: CrossRef {} => {}".format(rule_name,
resolved_rule.name))
def _resolve(self, parser, node):
return resolved_rule
def get_rule_by_name(rule_name):
if rule_name in parser.peg_rules:
return parser.peg_rules[rule_name]
else:
raise SemanticError("Rule \"{}\" does not exists."
.format(rule_name))
def second_pass(self, parser, node):
'''
Resolving cross-references in second pass.
'''
if parser.debug:
print("Second pass:", type(node), str(node))
if isinstance(node, ParsingExpression):
.format(n.rule_name))
for i, n in enumerate(node.nodes):
if isinstance(n, CrossRef):
resolved_rule = self._resolve(parser, n.rule_name)
rule_name = n.rule_name
if parser.debug:
print("Resolving crossref {}".format(rule_name))
resolved_rule = get_rule_by_name(rule_name)
while type(resolved_rule) is CrossRef:
target_rule = resolved_rule.rule_name
resolved_rule = get_rule_by_name(target_rule)
# If resolved rule hasn't got the same name it
# should be cloned and preserved in the peg_rules cache
if resolved_rule.rule_name != n.rule_name:
if resolved_rule.rule_name != rule_name:
resolved_rule = copy.copy(resolved_rule)
resolved_rule.rule_name = n.rule_name
parser.peg_rules[resolved_rule.rule_name] = resolved_rule
resolved_rule.rule_name = rule_name
parser.peg_rules[rule_name] = resolved_rule
if parser.debug:
print("Resolving: cloned to {} = > {}"\
.format(resolved_rule.rule_name, resolved_rule.name))
node.nodes[i] = resolved_rule
else:
resolved_rule = n
return node
elif not isinstance(node, CrossRef):
raise SemanticError("Invalid type '{}'({}) after first pass."
.format(type(node), str(node)))
if not resolved_rule in self.resolved:
self.resolved.add(resolved_rule)
self._resolve(parser, resolved_rule)
def second_pass(self, parser, node):
'''
Resolving cross-references in second pass.
'''
if parser.debug:
print("Second pass:", type(node), str(node))
class SemGrammar(SemanticAction):
def first_pass(self, parser, node, children):
return parser.peg_rules[parser.root_rule_name]
self.resolved = set()
self._resolve(parser, node)
return node
peggrammar.sem = SemGrammar()
class SemRule(PEGSemanticAction):
def first_pass(self, parser, node, children):
def sem_rule(parser, node, children):
rule_name = children[0]
if len(children) > 2:
retval = Sequence(nodes=children[1:])
else:
retval = children[1]
# CrossRef already has rule_name set
# that attrib is a target rule name
if type(retval) is not CrossRef:
retval.rule_name = rule_name
retval.root = True
......@@ -122,29 +122,26 @@ class SemRule(PEGSemanticAction):
# resolving.
parser.peg_rules[rule_name] = retval
return retval
rule.sem = sem_rule
class SemSequence(PEGSemanticAction):
def first_pass(self, parser, node, children):
def sem_sequence(parser, node, children):
if len(children) > 1:
return Sequence(nodes=children[:])
else:
# If only one child rule exists reduce.
return children[0]
sequence.sem = sem_sequence
class SemOrderedChoice(PEGSemanticAction):
def first_pass(self, parser, node, children):
def sem_ordered_choice(parser, node, children):
if len(children) > 1:
retval = OrderedChoice(nodes=children[:])
else:
# If only one child rule exists reduce.
retval = children[0]
return retval
ordered_choice.sem = sem_ordered_choice
class SemPrefix(PEGSemanticAction):
def first_pass(self, parser, node, children):
def sem_prefix(parser, node, children):
if len(children) == 2:
if children[0] == NOT():
retval = Not()
......@@ -159,10 +156,9 @@ class SemPrefix(PEGSemanticAction):
retval = children[0]
return retval
prefix.sem = sem_prefix
class SemSufix(PEGSemanticAction):
def first_pass(self, parser, node, children):
def sem_sufix(parser, node, children):
if len(children) == 2:
if children[1] == STAR():
retval = ZeroOrMore(children[0])
......@@ -178,43 +174,27 @@ class SemSufix(PEGSemanticAction):
retval = children[0]
return retval
sufix.sem = sem_sufix
class SemExpression(PEGSemanticAction):
def first_pass(self, parser, node, children):
return children[0]
class SemRuleCrossRef(SemanticAction):
def first_pass(self, parser, node, children):
def sem_rule_crossref(parser, node, children):
return CrossRef(node.value)
rule_crossref.sem = sem_rule_crossref
class SemRegEx(SemanticAction):
def first_pass(self, parser, node, children):
def sem_regex(parser, node, children):
match = RegExMatch(children[0],
ignore_case=parser.ignore_case)
match.compile()
return match
regex.sem = sem_regex
class SemStrMatch(SemanticAction):
def first_pass(self, parser, node, children):
def sem_strmatch(parser, node, children):
match_str = node.value[1:-1]
match_str = match_str.replace("\\'", "'")
match_str = match_str.replace("\\\\", "\\")
return StrMatch(match_str, ignore_case=parser.ignore_case)
str_match.sem = sem_strmatch
peggrammar.sem = SemGrammar()
rule.sem = SemRule()
ordered_choice.sem = SemOrderedChoice()
sequence.sem = SemSequence()
prefix.sem = SemPrefix()
sufix.sem = SemSufix()
expression.sem = SemExpression()
rule_crossref.sem = SemRuleCrossRef()
regex.sem = SemRegEx()
str_match.sem = SemStrMatch()
expression.sem = SemanticActionSingleChild()
class ParserPEG(Parser):
......
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