mirror of
https://github.com/thegeeklab/ansible-later.git
synced 2024-11-16 01:50:39 +00:00
134 lines
4.8 KiB
Python
134 lines
4.8 KiB
Python
#-----------------------------------------------------------------
|
|
# plyparser.py
|
|
#
|
|
# PLYParser class and other utilites for simplifying programming
|
|
# parsers with PLY
|
|
#
|
|
# Eli Bendersky [https://eli.thegreenplace.net/]
|
|
# License: BSD
|
|
#-----------------------------------------------------------------
|
|
|
|
import warnings
|
|
|
|
class Coord(object):
|
|
""" Coordinates of a syntactic element. Consists of:
|
|
- File name
|
|
- Line number
|
|
- (optional) column number, for the Lexer
|
|
"""
|
|
__slots__ = ('file', 'line', 'column', '__weakref__')
|
|
def __init__(self, file, line, column=None):
|
|
self.file = file
|
|
self.line = line
|
|
self.column = column
|
|
|
|
def __str__(self):
|
|
str = "%s:%s" % (self.file, self.line)
|
|
if self.column: str += ":%s" % self.column
|
|
return str
|
|
|
|
|
|
class ParseError(Exception): pass
|
|
|
|
|
|
class PLYParser(object):
|
|
def _create_opt_rule(self, rulename):
|
|
""" Given a rule name, creates an optional ply.yacc rule
|
|
for it. The name of the optional rule is
|
|
<rulename>_opt
|
|
"""
|
|
optname = rulename + '_opt'
|
|
|
|
def optrule(self, p):
|
|
p[0] = p[1]
|
|
|
|
optrule.__doc__ = '%s : empty\n| %s' % (optname, rulename)
|
|
optrule.__name__ = 'p_%s' % optname
|
|
setattr(self.__class__, optrule.__name__, optrule)
|
|
|
|
def _coord(self, lineno, column=None):
|
|
return Coord(
|
|
file=self.clex.filename,
|
|
line=lineno,
|
|
column=column)
|
|
|
|
def _token_coord(self, p, token_idx):
|
|
""" Returns the coordinates for the YaccProduction objet 'p' indexed
|
|
with 'token_idx'. The coordinate includes the 'lineno' and
|
|
'column'. Both follow the lex semantic, starting from 1.
|
|
"""
|
|
last_cr = p.lexer.lexer.lexdata.rfind('\n', 0, p.lexpos(token_idx))
|
|
if last_cr < 0:
|
|
last_cr = -1
|
|
column = (p.lexpos(token_idx) - (last_cr))
|
|
return self._coord(p.lineno(token_idx), column)
|
|
|
|
def _parse_error(self, msg, coord):
|
|
raise ParseError("%s: %s" % (coord, msg))
|
|
|
|
|
|
def parameterized(*params):
|
|
""" Decorator to create parameterized rules.
|
|
|
|
Parameterized rule methods must be named starting with 'p_' and contain
|
|
'xxx', and their docstrings may contain 'xxx' and 'yyy'. These will be
|
|
replaced by the given parameter tuples. For example, ``p_xxx_rule()`` with
|
|
docstring 'xxx_rule : yyy' when decorated with
|
|
``@parameterized(('id', 'ID'))`` produces ``p_id_rule()`` with the docstring
|
|
'id_rule : ID'. Using multiple tuples produces multiple rules.
|
|
"""
|
|
def decorate(rule_func):
|
|
rule_func._params = params
|
|
return rule_func
|
|
return decorate
|
|
|
|
|
|
def template(cls):
|
|
""" Class decorator to generate rules from parameterized rule templates.
|
|
|
|
See `parameterized` for more information on parameterized rules.
|
|
"""
|
|
issued_nodoc_warning = False
|
|
for attr_name in dir(cls):
|
|
if attr_name.startswith('p_'):
|
|
method = getattr(cls, attr_name)
|
|
if hasattr(method, '_params'):
|
|
# Remove the template method
|
|
delattr(cls, attr_name)
|
|
# Create parameterized rules from this method; only run this if
|
|
# the method has a docstring. This is to address an issue when
|
|
# pycparser's users are installed in -OO mode which strips
|
|
# docstrings away.
|
|
# See: https://github.com/eliben/pycparser/pull/198/ and
|
|
# https://github.com/eliben/pycparser/issues/197
|
|
# for discussion.
|
|
if method.__doc__ is not None:
|
|
_create_param_rules(cls, method)
|
|
elif not issued_nodoc_warning:
|
|
warnings.warn(
|
|
'parsing methods must have __doc__ for pycparser to work properly',
|
|
RuntimeWarning,
|
|
stacklevel=2)
|
|
issued_nodoc_warning = True
|
|
return cls
|
|
|
|
|
|
def _create_param_rules(cls, func):
|
|
""" Create ply.yacc rules based on a parameterized rule function
|
|
|
|
Generates new methods (one per each pair of parameters) based on the
|
|
template rule function `func`, and attaches them to `cls`. The rule
|
|
function's parameters must be accessible via its `_params` attribute.
|
|
"""
|
|
for xxx, yyy in func._params:
|
|
# Use the template method's body for each new method
|
|
def param_rule(self, p):
|
|
func(self, p)
|
|
|
|
# Substitute in the params for the grammar rule and function name
|
|
param_rule.__doc__ = func.__doc__.replace('xxx', xxx).replace('yyy', yyy)
|
|
param_rule.__name__ = func.__name__.replace('xxx', xxx)
|
|
|
|
# Attach the new method to the class
|
|
setattr(cls, param_rule.__name__, param_rule)
|