forked from VimPlug/jedi
87 lines
2.6 KiB
Python
87 lines
2.6 KiB
Python
"""
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Parsers for Python
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"""
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import os
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from jedi._compatibility import FileNotFoundError
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from jedi.parser.pgen2.pgen import generate_grammar
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from jedi.parser.python.parser import Parser, ParserWithRecovery
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from jedi.parser.tokenize import source_tokens
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_loaded_grammars = {}
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def load_grammar(version=None):
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"""
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Loads a Python grammar. The default version is always the latest.
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If you need support for a specific version, please use e.g.
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`version='3.3'`.
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"""
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if version is None:
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version = '3.6'
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if version in ('3.2', '3.3'):
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version = '3.4'
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elif version == '2.6':
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version = '2.7'
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file = 'grammar' + version + '.txt'
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global _loaded_grammars
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path = os.path.join(os.path.dirname(__file__), file)
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try:
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return _loaded_grammars[path]
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except KeyError:
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try:
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with open(path) as f:
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bnf_text = f.read()
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grammar = generate_grammar(bnf_text)
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return _loaded_grammars.setdefault(path, grammar)
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except FileNotFoundError:
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# Just load the default if the file does not exist.
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return load_grammar()
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def parse(code, grammar=None, error_recovery=True, start_symbol='file_input'):
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"""
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If you want to parse a Python file you want to start here, most likely.
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If you need finer grained control over the parsed instance, there will be
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other ways to access it.
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:param code: A unicode string that contains Python code.
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:param grammar: A Python grammar file, created with load_grammar.
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:param error_recovery: If enabled, any code will be returned. If it is
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invalid, it will be returned as an error node. If disabled, you will
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get a ParseError when encountering syntax errors in your code.
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:param start_symbol: The grammar symbol that you want to parse. Only
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allowed to be used when error_recovery is disabled.
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:return: A syntax tree node. Typically the module.
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"""
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if start_symbol != 'file_input' and error_recovery:
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raise Exception(
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'The start_symbol is only allowed when error recovery is disabled.')
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added_newline = not code.endswith('\n')
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if added_newline:
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code += '\n'
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if grammar is None:
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grammar = load_grammar()
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tokens = source_tokens(code, use_exact_op_types=True)
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kwargs = {}
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if error_recovery:
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parser = ParserWithRecovery
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else:
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kwargs = dict(start_symbol=start_symbol)
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parser = Parser
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p = parser(grammar, code, tokens=tokens, **kwargs)
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if added_newline:
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p._remove_last_newline()
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return p.get_root_node()
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