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parser_base.py
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2182 lines (1695 loc) · 73.1 KB
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# The file was automatically generated by Lark v0.8.5
#
#
# Lark Stand-alone Generator Tool
# ----------------------------------
# Generates a stand-alone LALR(1) parser with a standard lexer
#
# Git: https://github.com/erezsh/lark
# Author: Erez Shinan (erezshin@gmail.com)
#
###
# Modified: github/supposedly
###
#
# >>> LICENSE
#
# This tool and its generated code use a separate license from Lark,
# and are subject to the terms of the Mozilla Public License, v. 2.0.
# If a copy of the MPL was not distributed with this
# file, You can obtain one at https://mozilla.org/MPL/2.0/.
#
# If you wish to purchase a commercial license for this tool and its
# generated code, you may contact me via email or otherwise.
#
# If MPL2 is incompatible with your free or open-source project,
# contact me and we'll work it out.
#
#
import os
from io import open
class LarkError(Exception):
pass
class GrammarError(LarkError):
pass
class ParseError(LarkError):
pass
class LexError(LarkError):
pass
class UnexpectedEOF(ParseError):
def __init__(self, expected):
self.expected = expected
message = ("Unexpected end-of-input. Expected one of: \n\t* %s\n" % '\n\t* '.join(x.name for x in self.expected))
super(UnexpectedEOF, self).__init__(message)
class UnexpectedInput(LarkError):
pos_in_stream = None
def get_context(self, text, span=40):
pos = self.pos_in_stream
start = max(pos - span, 0)
end = pos + span
before = text[start:pos].rsplit('\n', 1)[-1]
after = text[pos:end].split('\n', 1)[0]
return before + after + '\n' + ' ' * len(before) + '^\n'
def match_examples(self, parse_fn, examples):
""" Given a parser instance and a dictionary mapping some label with
some malformed syntax examples, it'll return the label for the
example that bests matches the current error.
"""
assert self.state is not None, "Not supported for this exception"
candidate = None
for label, example in examples.items():
assert not isinstance(example, STRING_TYPE)
for malformed in example:
try:
parse_fn(malformed)
except UnexpectedInput as ut:
if ut.state == self.state:
try:
if ut.token == self.token: # Try exact match first
return label
except AttributeError:
pass
if not candidate:
candidate = label
return candidate
class UnexpectedCharacters(LexError, UnexpectedInput):
def __init__(self, seq, lex_pos, line, column, allowed=None, considered_tokens=None, state=None, token_history=None):
message = "No terminal defined for '%s' at line %d col %d" % (seq[lex_pos], line, column)
self.line = line
self.column = column
self.allowed = allowed
self.considered_tokens = considered_tokens
self.pos_in_stream = lex_pos
self.state = state
message += '\n\n' + self.get_context(seq)
if allowed:
message += '\nExpecting: %s\n' % allowed
if token_history:
message += '\nPrevious tokens: %s\n' % ', '.join(repr(t) for t in token_history)
super(UnexpectedCharacters, self).__init__(message)
class UnexpectedToken(ParseError, UnexpectedInput):
def __init__(self, token, expected, considered_rules=None, state=None):
self.token = token
self.expected = expected # XXX str shouldn't necessary
self.line = getattr(token, 'line', '?')
self.column = getattr(token, 'column', '?')
self.considered_rules = considered_rules
self.state = state
self.pos_in_stream = getattr(token, 'pos_in_stream', None)
message = ("Unexpected token %r at line %s, column %s.\n"
"Expected one of: \n\t* %s\n"
% (token, self.line, self.column, '\n\t* '.join(self.expected)))
super(UnexpectedToken, self).__init__(message)
class VisitError(LarkError):
"""VisitError is raised when visitors are interrupted by an exception
It provides the following attributes for inspection:
- obj: the tree node or token it was processing when the exception was raised
- orig_exc: the exception that cause it to fail
"""
def __init__(self, rule, obj, orig_exc):
self.obj = obj
self.orig_exc = orig_exc
message = 'Error trying to process rule "%s":\n\n%s' % (rule, orig_exc)
super(VisitError, self).__init__(message)
def classify(seq, key=None, value=None):
d = {}
for item in seq:
k = key(item) if (key is not None) else item
v = value(item) if (value is not None) else item
if k in d:
d[k].append(v)
else:
d[k] = [v]
return d
def _deserialize(data, namespace, memo):
if isinstance(data, dict):
if '__type__' in data: # Object
class_ = namespace[data['__type__']]
return class_.deserialize(data, memo)
elif '@' in data:
return memo[data['@']]
return {key:_deserialize(value, namespace, memo) for key, value in data.items()}
elif isinstance(data, list):
return [_deserialize(value, namespace, memo) for value in data]
return data
class Serialize(object):
def memo_serialize(self, types_to_memoize):
memo = SerializeMemoizer(types_to_memoize)
return self.serialize(memo), memo.serialize()
def serialize(self, memo=None):
if memo and memo.in_types(self):
return {'@': memo.memoized.get(self)}
fields = getattr(self, '__serialize_fields__')
res = {f: _serialize(getattr(self, f), memo) for f in fields}
res['__type__'] = type(self).__name__
postprocess = getattr(self, '_serialize', None)
if postprocess:
postprocess(res, memo)
return res
@classmethod
def deserialize(cls, data, memo):
namespace = getattr(cls, '__serialize_namespace__', {})
namespace = {c.__name__:c for c in namespace}
fields = getattr(cls, '__serialize_fields__')
if '@' in data:
return memo[data['@']]
inst = cls.__new__(cls)
for f in fields:
try:
setattr(inst, f, _deserialize(data[f], namespace, memo))
except KeyError as e:
raise KeyError("Cannot find key for class", cls, e)
postprocess = getattr(inst, '_deserialize', None)
if postprocess:
postprocess()
return inst
class SerializeMemoizer(Serialize):
__serialize_fields__ = 'memoized',
def __init__(self, types_to_memoize):
self.types_to_memoize = tuple(types_to_memoize)
self.memoized = Enumerator()
def in_types(self, value):
return isinstance(value, self.types_to_memoize)
def serialize(self):
return _serialize(self.memoized.reversed(), None)
@classmethod
def deserialize(cls, data, namespace, memo):
return _deserialize(data, namespace, memo)
try:
STRING_TYPE = basestring
except NameError: # Python 3
STRING_TYPE = str
import types
from functools import wraps, partial
from contextlib import contextmanager
Str = type(u'')
try:
classtype = types.ClassType # Python2
except AttributeError:
classtype = type # Python3
def smart_decorator(f, create_decorator):
if isinstance(f, types.FunctionType):
return wraps(f)(create_decorator(f, True))
elif isinstance(f, (classtype, type, types.BuiltinFunctionType)):
return wraps(f)(create_decorator(f, False))
elif isinstance(f, types.MethodType):
return wraps(f)(create_decorator(f.__func__, True))
elif isinstance(f, partial):
# wraps does not work for partials in 2.7: https://bugs.python.org/issue3445
return wraps(f.func)(create_decorator(lambda *args, **kw: f(*args[1:], **kw), True))
else:
return create_decorator(f.__func__.__call__, True)
import sys, re
Py36 = (sys.version_info[:2] >= (3, 6))
import sre_parse
import sre_constants
def get_regexp_width(regexp):
try:
return [int(x) for x in sre_parse.parse(regexp).getwidth()]
except sre_constants.error:
raise ValueError(regexp)
class Meta:
def __init__(self):
self.empty = True
class Tree(object):
def __init__(self, data, children, meta=None):
self.data = data
self.children = children
self._meta = meta
@property
def meta(self):
if self._meta is None:
self._meta = Meta()
return self._meta
def __repr__(self):
return 'Tree(%s, %s)' % (self.data, self.children)
def _pretty_label(self):
return self.data
def _pretty(self, level, indent_str):
if len(self.children) == 1 and not isinstance(self.children[0], Tree):
return [ indent_str*level, self._pretty_label(), '\t', '%s' % (self.children[0],), '\n']
l = [ indent_str*level, self._pretty_label(), '\n' ]
for n in self.children:
if isinstance(n, Tree):
l += n._pretty(level+1, indent_str)
else:
l += [ indent_str*(level+1), '%s' % (n,), '\n' ]
return l
def pretty(self, indent_str=' '):
return ''.join(self._pretty(0, indent_str))
def __eq__(self, other):
try:
return self.data == other.data and self.children == other.children
except AttributeError:
return False
def __ne__(self, other):
return not (self == other)
def __hash__(self):
return hash((self.data, tuple(self.children)))
def iter_subtrees(self):
queue = [self]
subtrees = OrderedDict()
for subtree in queue:
subtrees[id(subtree)] = subtree
queue += [c for c in reversed(subtree.children)
if isinstance(c, Tree) and id(c) not in subtrees]
del queue
return reversed(list(subtrees.values()))
def find_pred(self, pred):
"Find all nodes where pred(tree) == True"
return filter(pred, self.iter_subtrees())
def find_data(self, data):
"Find all nodes where tree.data == data"
return self.find_pred(lambda t: t.data == data)
from inspect import getmembers, getmro
class Discard(Exception):
pass
# Transformers
class _Decoratable:
@classmethod
def _apply_decorator(cls, decorator, **kwargs):
mro = getmro(cls)
assert mro[0] is cls
libmembers = {name for _cls in mro[1:] for name, _ in getmembers(_cls)}
for name, value in getmembers(cls):
# Make sure the function isn't inherited (unless it's overwritten)
if name.startswith('_') or (name in libmembers and name not in cls.__dict__):
continue
if not callable(value):
continue
# Skip if v_args already applied (at the function level)
if hasattr(cls.__dict__[name], 'vargs_applied') or hasattr(value, 'vargs_applied'):
continue
static = isinstance(cls.__dict__[name], (staticmethod, classmethod))
setattr(cls, name, decorator(value, static=static, **kwargs))
return cls
def __class_getitem__(cls, _):
return cls
class Transformer(_Decoratable):
"""Visits the tree recursively, starting with the leaves and finally the root (bottom-up)
Calls its methods (provided by user via inheritance) according to tree.data
The returned value replaces the old one in the structure.
Can be used to implement map or reduce.
"""
__visit_tokens__ = True # For backwards compatibility
def __init__(self, visit_tokens=True):
self.__visit_tokens__ = visit_tokens
def _call_userfunc(self, tree, new_children=None):
# Assumes tree is already transformed
children = new_children if new_children is not None else tree.children
try:
f = getattr(self, tree.data)
except AttributeError:
return self.__default__(tree.data, children, tree.meta)
else:
try:
wrapper = getattr(f, 'visit_wrapper', None)
if wrapper is not None:
return f.visit_wrapper(f, tree.data, children, tree.meta)
else:
return f(children)
except (GrammarError, Discard):
raise
except Exception as e:
raise# VisitError(tree.data, tree, e)
def _call_userfunc_token(self, token):
try:
f = getattr(self, token.type)
except AttributeError:
return self.__default_token__(token)
else:
try:
return f(token)
except (GrammarError, Discard):
raise
except Exception as e:
raise VisitError(token.type, token, e)
def _transform_children(self, children):
for c in children:
try:
if isinstance(c, Tree):
yield self._transform_tree(c)
elif self.__visit_tokens__ and isinstance(c, Token):
yield self._call_userfunc_token(c)
else:
yield c
except Discard:
pass
def _transform_tree(self, tree):
children = list(self._transform_children(tree.children))
return self._call_userfunc(tree, children)
def transform(self, tree):
return self._transform_tree(tree)
def __mul__(self, other):
return TransformerChain(self, other)
def __default__(self, data, children, meta):
"Default operation on tree (for override)"
return Tree(data, children, meta)
def __default_token__(self, token):
"Default operation on token (for override)"
return token
class InlineTransformer(Transformer): # XXX Deprecated
def _call_userfunc(self, tree, new_children=None):
# Assumes tree is already transformed
children = new_children if new_children is not None else tree.children
try:
f = getattr(self, tree.data)
except AttributeError:
return self.__default__(tree.data, children, tree.meta)
else:
return f(*children)
class TransformerChain(object):
def __init__(self, *transformers):
self.transformers = transformers
def transform(self, tree):
for t in self.transformers:
tree = t.transform(tree)
return tree
def __mul__(self, other):
return TransformerChain(*self.transformers + (other,))
class Transformer_InPlace(Transformer):
"Non-recursive. Changes the tree in-place instead of returning new instances"
def _transform_tree(self, tree): # Cancel recursion
return self._call_userfunc(tree)
def transform(self, tree):
for subtree in tree.iter_subtrees():
subtree.children = list(self._transform_children(subtree.children))
return self._transform_tree(tree)
class Transformer_NonRecursive(Transformer):
"Non-recursive. Doesn't change the original tree."
def transform(self, tree):
# Tree to postfix
rev_postfix = []
q = [tree]
while q:
t = q.pop()
rev_postfix.append( t )
if isinstance(t, Tree):
q += t.children
# Postfix to tree
stack = []
for x in reversed(rev_postfix):
if isinstance(x, Tree):
size = len(x.children)
if size:
args = stack[-size:]
del stack[-size:]
else:
args = []
stack.append(self._call_userfunc(x, args))
else:
stack.append(x)
t ,= stack # We should have only one tree remaining
return t
class Transformer_InPlaceRecursive(Transformer):
"Recursive. Changes the tree in-place instead of returning new instances"
def _transform_tree(self, tree):
tree.children = list(self._transform_children(tree.children))
return self._call_userfunc(tree)
# Visitors
class VisitorBase:
def _call_userfunc(self, tree):
return getattr(self, tree.data, self.__default__)(tree)
def __default__(self, tree):
"Default operation on tree (for override)"
return tree
def __class_getitem__(cls, _):
return cls
class Visitor(VisitorBase):
"""Bottom-up visitor, non-recursive
Visits the tree, starting with the leaves and finally the root (bottom-up)
Calls its methods (provided by user via inheritance) according to tree.data
"""
def visit(self, tree):
for subtree in tree.iter_subtrees():
self._call_userfunc(subtree)
return tree
def visit_topdown(self,tree):
for subtree in tree.iter_subtrees_topdown():
self._call_userfunc(subtree)
return tree
class Visitor_Recursive(VisitorBase):
"""Bottom-up visitor, recursive
Visits the tree, starting with the leaves and finally the root (bottom-up)
Calls its methods (provided by user via inheritance) according to tree.data
"""
def visit(self, tree):
for child in tree.children:
if isinstance(child, Tree):
self.visit(child)
self._call_userfunc(tree)
return tree
def visit_topdown(self,tree):
self._call_userfunc(tree)
for child in tree.children:
if isinstance(child, Tree):
self.visit_topdown(child)
return tree
def visit_children_decor(func):
"See Interpreter"
@wraps(func)
def inner(cls, tree):
values = cls.visit_children(tree)
return func(cls, values)
return inner
class Interpreter(_Decoratable):
"""Top-down visitor, recursive
Visits the tree, starting with the root and finally the leaves (top-down)
Calls its methods (provided by user via inheritance) according to tree.data
Unlike Transformer and Visitor, the Interpreter doesn't automatically visit its sub-branches.
The user has to explicitly call visit_children, or use the @visit_children_decor
"""
def visit(self, tree):
f = getattr(self, tree.data)
wrapper = getattr(f, 'visit_wrapper', None)
if wrapper is not None:
return f.visit_wrapper(f, tree.data, tree.children, tree.meta)
else:
return f(tree)
def visit_children(self, tree):
return [self.visit(child) if isinstance(child, Tree) else child
for child in tree.children]
def __getattr__(self, name):
return self.__default__
def __default__(self, tree):
return self.visit_children(tree)
# Decorators
def _apply_decorator(obj, decorator, **kwargs):
try:
_apply = obj._apply_decorator
except AttributeError:
return decorator(obj, **kwargs)
else:
return _apply(decorator, **kwargs)
def _inline_args__func(func):
@wraps(func)
def create_decorator(_f, with_self):
if with_self:
def f(self, children):
return _f(self, *children)
else:
def f(self, children):
return _f(*children)
return f
return smart_decorator(func, create_decorator)
def inline_args(obj): # XXX Deprecated
return _apply_decorator(obj, _inline_args__func)
def _visitor_args_func_dec(func, visit_wrapper=None, static=False):
def create_decorator(_f, with_self):
if with_self:
def f(self, *args, **kwargs):
return _f(self, *args, **kwargs)
else:
def f(self, *args, **kwargs):
return _f(*args, **kwargs)
return f
if static:
f = wraps(func)(create_decorator(func, False))
else:
f = smart_decorator(func, create_decorator)
f.vargs_applied = True
f.visit_wrapper = visit_wrapper
return f
def _vargs_inline(f, data, children, meta):
return f(*children)
def _vargs_meta_inline(f, data, children, meta):
return f(meta, *children)
def _vargs_meta(f, data, children, meta):
return f(children, meta) # TODO swap these for consistency? Backwards incompatible!
def _vargs_tree(f, data, children, meta):
return f(Tree(data, children, meta))
def v_args(inline=False, meta=False, tree=False, wrapper=None):
"A convenience decorator factory, for modifying the behavior of user-supplied visitor methods"
if tree and (meta or inline):
raise ValueError("Visitor functions cannot combine 'tree' with 'meta' or 'inline'.")
func = None
if meta:
if inline:
func = _vargs_meta_inline
else:
func = _vargs_meta
elif inline:
func = _vargs_inline
elif tree:
func = _vargs_tree
if wrapper is not None:
if func is not None:
raise ValueError("Cannot use 'wrapper' along with 'tree', 'meta' or 'inline'.")
func = wrapper
def _visitor_args_dec(obj):
return _apply_decorator(obj, _visitor_args_func_dec, visit_wrapper=func)
return _visitor_args_dec
class Indenter:
def __init__(self):
self.paren_level = None
self.indent_level = None
assert self.tab_len > 0
def handle_NL(self, token):
if self.paren_level > 0:
return
yield token
indent_str = token.rsplit('\n', 1)[1] # Tabs and spaces
indent = indent_str.count(' ') + indent_str.count('\t') * self.tab_len
if indent > self.indent_level[-1]:
self.indent_level.append(indent)
yield Token.new_borrow_pos(self.INDENT_type, indent_str, token)
else:
while indent < self.indent_level[-1]:
self.indent_level.pop()
yield Token.new_borrow_pos(self.DEDENT_type, indent_str, token)
assert indent == self.indent_level[-1], '%s != %s' % (indent, self.indent_level[-1])
def _process(self, stream):
for token in stream:
if token.type == self.NL_type:
for t in self.handle_NL(token):
yield t
else:
yield token
if token.type in self.OPEN_PAREN_types:
self.paren_level += 1
elif token.type in self.CLOSE_PAREN_types:
self.paren_level -= 1
assert self.paren_level >= 0
while len(self.indent_level) > 1:
self.indent_level.pop()
yield Token(self.DEDENT_type, '')
assert self.indent_level == [0], self.indent_level
def process(self, stream):
self.paren_level = 0
self.indent_level = [0]
return self._process(stream)
# XXX Hack for ContextualLexer. Maybe there's a more elegant solution?
@property
def always_accept(self):
return (self.NL_type,)
class Symbol(Serialize):
__slots__ = ('name',)
is_term = NotImplemented
def __init__(self, name):
self.name = name
def __eq__(self, other):
assert isinstance(other, Symbol), other
return self.is_term == other.is_term and self.name == other.name
def __ne__(self, other):
return not (self == other)
def __hash__(self):
return hash(self.name)
def __repr__(self):
return '%s(%r)' % (type(self).__name__, self.name)
fullrepr = property(__repr__)
class Terminal(Symbol):
__serialize_fields__ = 'name', 'filter_out'
is_term = True
def __init__(self, name, filter_out=False):
self.name = name
self.filter_out = filter_out
@property
def fullrepr(self):
return '%s(%r, %r)' % (type(self).__name__, self.name, self.filter_out)
class NonTerminal(Symbol):
__serialize_fields__ = 'name',
is_term = False
class RuleOptions(Serialize):
__serialize_fields__ = 'keep_all_tokens', 'expand1', 'priority', 'template_source', 'empty_indices'
def __init__(self, keep_all_tokens=False, expand1=False, priority=None, template_source=None, empty_indices=()):
self.keep_all_tokens = keep_all_tokens
self.expand1 = expand1
self.priority = priority
self.template_source = template_source
self.empty_indices = empty_indices
def __repr__(self):
return 'RuleOptions(%r, %r, %r, %r)' % (
self.keep_all_tokens,
self.expand1,
self.priority,
self.template_source
)
class Rule(Serialize):
"""
origin : a symbol
expansion : a list of symbols
order : index of this expansion amongst all rules of the same name
"""
__slots__ = ('origin', 'expansion', 'alias', 'options', 'order', '_hash')
__serialize_fields__ = 'origin', 'expansion', 'order', 'alias', 'options'
__serialize_namespace__ = Terminal, NonTerminal, RuleOptions
def __init__(self, origin, expansion, order=0, alias=None, options=None):
self.origin = origin
self.expansion = expansion
self.alias = alias
self.order = order
self.options = options or RuleOptions()
self._hash = hash((self.origin, tuple(self.expansion)))
def _deserialize(self):
self._hash = hash((self.origin, tuple(self.expansion)))
def __str__(self):
return '<%s : %s>' % (self.origin.name, ' '.join(x.name for x in self.expansion))
def __repr__(self):
return 'Rule(%r, %r, %r, %r)' % (self.origin, self.expansion, self.alias, self.options)
def __hash__(self):
return self._hash
def __eq__(self, other):
if not isinstance(other, Rule):
return False
return self.origin == other.origin and self.expansion == other.expansion
class Pattern(Serialize):
def __init__(self, value, flags=()):
self.value = value
self.flags = frozenset(flags)
def __repr__(self):
return repr(self.to_regexp())
# Pattern Hashing assumes all subclasses have a different priority!
def __hash__(self):
return hash((type(self), self.value, self.flags))
def __eq__(self, other):
return type(self) == type(other) and self.value == other.value and self.flags == other.flags
def to_regexp(self):
raise NotImplementedError()
if Py36:
# Python 3.6 changed syntax for flags in regular expression
def _get_flags(self, value):
for f in self.flags:
value = ('(?%s:%s)' % (f, value))
return value
else:
def _get_flags(self, value):
for f in self.flags:
value = ('(?%s)' % f) + value
return value
class PatternStr(Pattern):
__serialize_fields__ = 'value', 'flags'
type = "str"
def to_regexp(self):
return self._get_flags(re.escape(self.value))
@property
def min_width(self):
return len(self.value)
max_width = min_width
class PatternRE(Pattern):
__serialize_fields__ = 'value', 'flags', '_width'
type = "re"
def to_regexp(self):
return self._get_flags(self.value)
_width = None
def _get_width(self):
if self._width is None:
self._width = get_regexp_width(self.to_regexp())
return self._width
@property
def min_width(self):
return self._get_width()[0]
@property
def max_width(self):
return self._get_width()[1]
class TerminalDef(Serialize):
__serialize_fields__ = 'name', 'pattern', 'priority'
__serialize_namespace__ = PatternStr, PatternRE
def __init__(self, name, pattern, priority=1):
assert isinstance(pattern, Pattern), pattern
self.name = name
self.pattern = pattern
self.priority = priority
def __repr__(self):
return '%s(%r, %r)' % (type(self).__name__, self.name, self.pattern)
class Token(Str):
__slots__ = ('type', 'pos_in_stream', 'value', 'line', 'column', 'end_line', 'end_column', 'end_pos')
def __new__(cls, type_, value, pos_in_stream=None, line=None, column=None, end_line=None, end_column=None, end_pos=None, tbl=None):
try:
self = super(Token, cls).__new__(cls, value)
except UnicodeDecodeError:
value = value.decode('latin1')
self = super(Token, cls).__new__(cls, value)
if tbl is None:
raise Exception()
if tbl is not None and type_ == 'STATE' and int(value) >= tbl.n_states:
tbl.n_states = 1 + int(value)
self.type = type_
self.pos_in_stream = pos_in_stream
self.value = value
self.line = line
self.column = column
self.end_line = end_line
self.end_column = end_column
self.end_pos = end_pos
return self
def update(self, type_=None, value=None):
return Token.new_borrow_pos(
type_ if type_ is not None else self.type,
value if value is not None else self.value,
self
)
@classmethod
def new_borrow_pos(cls, type_, value, borrow_t, tbl=None):
return cls(type_, value, borrow_t.pos_in_stream, borrow_t.line, borrow_t.column, borrow_t.end_line, borrow_t.end_column, borrow_t.end_pos, tbl=tbl)
def __reduce__(self):
return (self.__class__, (self.type, self.value, self.pos_in_stream, self.line, self.column, ))
def __repr__(self):
return 'Token(%s, %r)' % (self.type, self.value)
def __deepcopy__(self, memo):
return Token(self.type, self.value, self.pos_in_stream, self.line, self.column)
def __eq__(self, other):