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Commit 3fbcf6cd authored by Eckhart Arnold's avatar Eckhart Arnold
Browse files

- guarded_call: Small fixes of potential bugs

parent 24b39899
......@@ -92,6 +92,43 @@ MAX_DROPOUTS = 3 # type: int
# stop trying to recover parsing after so many errors
class ParserError(Exception):
A `ParserError` is thrown for those parser errors that allow the
controlled re-entrance of the parsion process after the error occured.
If a reentry-rule has been configured for the parser where the error
occured, the parser guard can resume the parsing process.
Currently, the only case when a `ParserError` is thrown (and not some
different kind of error like `UnknownParserError`, is when a `Series`-
detects a missing mandatory element.
def __init__(self,
parser: ParserBase,
node: Node,
remaining: StringView,
error: Error):
self.parser = parser # type: Parser
self.node = node # type: Node
self.remaining = remaining # type: StringView
self.error = error # type: Error
def location(self):
return self.parser.grammar.document_length__ - len(self.remaining)
# to be continued...
# class ReentryRule:
# """
# A rule for reentering the parsing process after a ParserError was thrown.
# """
# def __init__(self, parser: ParserBase, fast_forward_re: str):
# self.parser = parser # type: List[Parser]
# self.rules = # type: Sequence[Tuple[str, str]]
def add_parser_guard(parser_func):
Add a wrapper function to a parser functions (i.e. Parser.__call__ method)
......@@ -99,10 +136,10 @@ def add_parser_guard(parser_func):
(aka "history tracking") of parser calls. Returns the wrapped call.
def guarded_call(parser: 'Parser', text: StringView) -> Tuple[Optional[Node], StringView]:
grammar = parser.grammar
location = grammar.document_length__ - len(text)
grammar = parser.grammar
location = grammar.document_length__ - len(text)
if grammar.last_rb__loc__ >= location:
......@@ -112,10 +149,6 @@ def add_parser_guard(parser_func):
# no history recording in case of memoized results
return parser.visited[location]
if grammar.history_tracking__:
grammar.moving_forward__ = True
# break left recursion at the maximum allowed depth
if grammar.left_recursion_handling__:
if parser.recursion_counter[location] > LEFT_RECURSION_DEPTH:
......@@ -123,6 +156,10 @@ def add_parser_guard(parser_func):
return None, text
parser.recursion_counter[location] += 1
if grammar.history_tracking__:
grammar.moving_forward__ = True
# PARSER CALL: run original __call__ method
node, rest = parser_func(parser, text)
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