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94 lines
2.4 KiB
94 lines
2.4 KiB
4 years ago
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#!/usr/bin/python
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import argparse
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from nltk.parse.generate import generate
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from nltk import CFG
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from os.path import exists
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from sys import exit as sys_exit
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DEMO_GRAMMAR = """
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S -> 'import ' ImportList ';' | 'static import ' ImportList ';'
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ImportList -> Import | ImportBindings | Import ', ' ImportList
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Import -> ModuleFullyQualifiedName | ModuleAliasIdentifier ' = ' ModuleFullyQualifiedName
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ImportBindings -> Import ' : ' ImportBindList
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ImportBindList -> ImportBind | ImportBind ', ' ImportBindList
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ImportBind -> Identifier | Identifier ' = ' Identifier
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ModuleAliasIdentifier -> Identifier
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Packages -> PackageName | Packages '.' PackageName
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ModuleFullyQualifiedName -> ModuleName | Packages '.' ModuleName
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PackageName -> Identifier
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ModuleName -> Identifier
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Identifier -> 'x'
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"""
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def valid_file(arg_parser, *args):
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"""
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checks if on of the provided paths is a file
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Parameters
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----------------------------------------------------------------------------
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:param arg_parser:
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argument parser object that is called if no file is found
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:param args: list< str >
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a list of file path that is going to be checked
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:return: str
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----------------------------------------------------------------------------
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path to an existing file
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"""
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arg = None
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found_flag = False
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for arg in args:
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if exists(arg):
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found_flag = True
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break
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if not found_flag:
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arg_parser.error("file(s) do not exist: %s" % args)
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return arg
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def main(args):
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grammar_string = DEMO_GRAMMAR
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if args.input_file_path:
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with open(args.input_file_path, 'r') as f:
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grammar_string = f.read()
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grammar = CFG.fromstring(grammar_string)
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for sentence in generate(grammar, depth=args.depth):
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print(''.join(sentence))
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return 0
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if __name__ == "__main__":
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arg_parser = argparse.ArgumentParser()
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arg_parser.add_argument(
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'-i', '--input_file_path',
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metavar='<path>',
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type=lambda x: valid_file(arg_parser, x),
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help="Path to the grammar file",
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required=False
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)
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arg_parser.add_argument(
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'-d', '--depth',
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metavar='<nr>',
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type=int,
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default=9,
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help='Max depth of grammar tree.'
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)
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FLAGS, unparsed = arg_parser.parse_known_args()
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sys_exit(main(FLAGS))
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