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110 lines
4.5 KiB
Python
110 lines
4.5 KiB
Python
import hashlib
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from parso.pgen2.pgen import generate_grammar
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from parso.utils import splitlines, source_to_unicode
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from parso.python.parser import Parser, remove_last_newline
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from parso.python.diff import DiffParser
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from parso.tokenize import generate_tokens
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from parso.cache import parser_cache, load_module, save_module
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class Grammar(object):
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def __init__(self, bnf_text, tokenizer, parser, diff_parser=None):
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self._pgen_grammar = generate_grammar(bnf_text)
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self._parser = parser
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self._tokenizer = tokenizer
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self._diff_parser = diff_parser
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self._sha256 = hashlib.sha256(bnf_text.encode("utf-8")).hexdigest()
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def parse(self, code=None, **kwargs):
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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 path: The path to the file you want to open. Only needed for caching.
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:param grammar: A Python grammar file, created with load_grammar. You may
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not specify it. In that case it's the current Python version.
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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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:param cache_path: If given saves the parso cache in this directory. If not
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given, defaults to the default cache places on each platform.
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:return: A syntax tree node. Typically the module.
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"""
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return self._parse(code=code, **kwargs)
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def _parse(self, code=None, path=None, error_recovery=True,
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start_symbol='file_input', cache=False, diff_cache=False,
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cache_path=None):
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"""
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Wanted python3.5 * operator and keyword only arguments. Therefore just
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wrap it all.
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"""
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if code is None and path is None:
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raise TypeError("Please provide either code or a path.")
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if cache and code is None and path is not None:
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# With the current architecture we cannot load from cache if the
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# code is given, because we just load from cache if it's not older than
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# the latest change (file last modified).
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module_node = load_module(self, path, cache_path=cache_path)
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if module_node is not None:
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return module_node
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if code is None:
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with open(path, 'rb') as f:
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code = source_to_unicode(f.read())
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lines = tokenize_lines = splitlines(code, keepends=True)
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if diff_cache:
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try:
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module_cache_item = parser_cache[path]
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except KeyError:
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pass
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else:
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module_node = module_cache_item.node
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old_lines = module_cache_item.lines
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if old_lines == lines:
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# TODO remove this line? I think it's not needed. (dave)
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save_module(self, path, module_node, lines, pickling=False,
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cache_path=cache_path)
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return module_node
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new_node = DiffParser(self._pgen_grammar, module_node).update(
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old_lines=old_lines,
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new_lines=lines
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)
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save_module(self, path, new_node, lines, pickling=cache,
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cache_path=cache_path)
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return new_node
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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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tokenize_lines = list(tokenize_lines)
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tokenize_lines[-1] += '\n'
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tokenize_lines.append('')
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tokens = generate_tokens(tokenize_lines, use_exact_op_types=True)
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p = Parser(self._pgen_grammar, error_recovery=error_recovery, start_symbol=start_symbol)
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root_node = p.parse(tokens=tokens)
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if added_newline:
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remove_last_newline(root_node)
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if cache or diff_cache:
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save_module(self, path, root_node, lines, pickling=cache,
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cache_path=cache_path)
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return root_node
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def __repr__(self):
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labels = self._pgen_grammar.symbol2number.values()
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txt = ' '.join(list(labels)[:3]) + ' ...'
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return '<%s:%s>' % (self.__class__.__name__, txt)
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