import logging
import os
import pickle
import sys
import traceback
import ply
from ply import yacc
from ..configuration import Configuration
configuration = Configuration()
[docs]
class Parser:
"""
Abstract base class for Abjad parsers.
Rules objects for lexing and parsing must be defined by overriding the
abstract properties ``lexer_rules_object`` and ``parser_rules_object``.
For most parsers these properties should simply return ``self``.
"""
### CLASS VARIABLES ###
__slots__ = ("_debug", "_lexer", "_logger", "_parser")
_is_abstract = True
### INITIALIZER ###
def __init__(self, debug=False):
self._debug = bool(debug)
self._lexer = None
self._parser = None
if self.debug():
logging.basicConfig(
level=logging.DEBUG,
filename=self.logger_path(),
filemode="w",
format="%(filename)10s:%(lineno)8d:%(message)s",
)
self._logger = logging.getLogger()
else:
self._logger = yacc.NullLogger()
self._lexer = ply.lex.lex(
debug=self.debug(),
debuglog=self.logger(),
object=self.lexer_rules_object(),
)
if self.pickle_path() and not os.path.exists(self.pickle_path()):
try:
directory, _ = os.path.split(self.pickle_path())
if not os.path.exists(directory):
os.makedirs(directory)
string = pickle.dumps(None)
with open(self.pickle_path(), "wb") as file_pointer:
file_pointer.write(string)
except (IOError, OSError):
traceback.print_exc()
self._parser = ply.yacc.yacc(
debug=self.debug(),
debuglog=self.logger(),
module=self.parser_rules_object(),
outputdir=self.output_path(),
picklefile=self.pickle_path(),
)
### SPECIAL METHODS ###
def __call__(self, string):
"""
Parses ``string`` and returns result.
"""
if hasattr(self, "_setup"):
self._setup()
if self.debug():
result = self.parser().parse_debug(
string, lexer=self.lexer(), debug=self.logger()
)
else:
result = self.parser().parse(string, lexer=self.lexer())
if hasattr(self, "_cleanup"):
result = self._cleanup(result)
return result
### PUBLIC METHODS ###
[docs]
def tokenize(self, string):
"""
Tokenizes ``string`` and print results.
"""
self.lexer().input(string)
for token in self.lexer():
print(token)
[docs]
def debug(self):
"""
Is true when parser runs in debugging mode.
"""
return self._debug
[docs]
def lexer(self):
"""
Gets parser's PLY Lexer instance.
"""
return self._lexer
[docs]
def logger(self):
"""
Gets parser's logger.
"""
return self._logger
[docs]
def logger_path(self):
"""
Gets parser's logfile output path.
"""
if self.output_path() is None:
return None
string = "-".join(str(x) for x in sys.version_info)
file_name = f"parselog_{type(self).__name__}_{string}.txt"
return os.path.join(self.output_path(), file_name)
[docs]
def output_path(self):
"""
Gets output path for files associated with the parser.
"""
output_path = configuration.abjad_configuration_directory() / "parsers"
if not output_path.is_dir():
try:
os.makedirs(output_path)
except (IOError, OSError):
return None
return output_path
[docs]
def parser(self):
"""
Gets parser's PLY LRParser instance.
"""
return self._parser
[docs]
def pickle_path(self):
"""
Gets output path for the parser's pickled parsing tables.
"""
if self.output_path() is None:
return None
string = "-".join(str(x) for x in sys.version_info)
file_name = f"parse_tables_{type(self).__name__}_{string}.pkl"
return os.path.join(self.output_path(), file_name)