forked from VimPlug/jedi
Move the python parser.
This commit is contained in:
Dave Halter
292
jedi/parser/python/parser.py
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292
jedi/parser/python/parser.py
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import re
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from jedi.parser import tree as pt
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from jedi.parser import tokenize
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from jedi.parser.token import (DEDENT, INDENT, ENDMARKER, NEWLINE, NUMBER,
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STRING, tok_name)
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from jedi.parser.pgen2.parse import PgenParser
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from jedi.parser.parser import ParserSyntaxError
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class Parser(object):
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AST_MAPPING = {
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'expr_stmt': pt.ExprStmt,
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'classdef': pt.Class,
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'funcdef': pt.Function,
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'file_input': pt.Module,
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'import_name': pt.ImportName,
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'import_from': pt.ImportFrom,
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'break_stmt': pt.KeywordStatement,
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'continue_stmt': pt.KeywordStatement,
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'return_stmt': pt.ReturnStmt,
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'raise_stmt': pt.KeywordStatement,
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'yield_expr': pt.YieldExpr,
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'del_stmt': pt.KeywordStatement,
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'pass_stmt': pt.KeywordStatement,
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'global_stmt': pt.GlobalStmt,
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'nonlocal_stmt': pt.KeywordStatement,
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'print_stmt': pt.KeywordStatement,
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'assert_stmt': pt.AssertStmt,
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'if_stmt': pt.IfStmt,
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'with_stmt': pt.WithStmt,
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'for_stmt': pt.ForStmt,
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'while_stmt': pt.WhileStmt,
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'try_stmt': pt.TryStmt,
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'comp_for': pt.CompFor,
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'decorator': pt.Decorator,
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'lambdef': pt.Lambda,
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'old_lambdef': pt.Lambda,
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'lambdef_nocond': pt.Lambda,
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}
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def __init__(self, grammar, source, start_symbol='file_input',
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tokens=None, start_parsing=True):
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# Todo Remove start_parsing (with False)
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self._used_names = {}
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self.source = source
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self._added_newline = False
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# The Python grammar needs a newline at the end of each statement.
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if not source.endswith('\n') and start_symbol == 'file_input':
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source += '\n'
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self._added_newline = True
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self._start_symbol = start_symbol
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self._grammar = grammar
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self._parsed = None
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if start_parsing:
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if tokens is None:
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tokens = tokenize.source_tokens(source, use_exact_op_types=True)
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self.parse(tokens)
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def parse(self, tokens):
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if self._parsed is not None:
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return self._parsed
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start_number = self._grammar.symbol2number[self._start_symbol]
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self.pgen_parser = PgenParser(
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self._grammar, self.convert_node, self.convert_leaf,
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self.error_recovery, start_number
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)
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self._parsed = self.pgen_parser.parse(tokens)
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if self._start_symbol == 'file_input' != self._parsed.type:
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# If there's only one statement, we get back a non-module. That's
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# not what we want, we want a module, so we add it here:
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self._parsed = self.convert_node(self._grammar,
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self._grammar.symbol2number['file_input'],
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[self._parsed])
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if self._added_newline:
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self.remove_last_newline()
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# The stack is empty now, we don't need it anymore.
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del self.pgen_parser
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return self._parsed
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def get_parsed_node(self):
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# TODO remove in favor of get_root_node
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return self._parsed
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def get_root_node(self):
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return self._parsed
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def error_recovery(self, grammar, stack, arcs, typ, value, start_pos, prefix,
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add_token_callback):
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raise ParserSyntaxError('SyntaxError: invalid syntax', start_pos)
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def convert_node(self, grammar, type, children):
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"""
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Convert raw node information to a Node instance.
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This is passed to the parser driver which calls it whenever a reduction of a
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grammar rule produces a new complete node, so that the tree is build
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strictly bottom-up.
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"""
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symbol = grammar.number2symbol[type]
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try:
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return Parser.AST_MAPPING[symbol](children)
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except KeyError:
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if symbol == 'suite':
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# We don't want the INDENT/DEDENT in our parser tree. Those
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# leaves are just cancer. They are virtual leaves and not real
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# ones and therefore have pseudo start/end positions and no
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# prefixes. Just ignore them.
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children = [children[0]] + children[2:-1]
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return pt.Node(symbol, children)
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def convert_leaf(self, grammar, type, value, prefix, start_pos):
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# print('leaf', repr(value), token.tok_name[type])
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if type == tokenize.NAME:
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if value in grammar.keywords:
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return pt.Keyword(value, start_pos, prefix)
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else:
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name = pt.Name(value, start_pos, prefix)
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# Keep a listing of all used names
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arr = self._used_names.setdefault(name.value, [])
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arr.append(name)
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return name
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elif type == STRING:
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return pt.String(value, start_pos, prefix)
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elif type == NUMBER:
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return pt.Number(value, start_pos, prefix)
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elif type == NEWLINE:
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return pt.Newline(value, start_pos, prefix)
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elif type == ENDMARKER:
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return pt.EndMarker(value, start_pos, prefix)
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else:
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return pt.Operator(value, start_pos, prefix)
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def remove_last_newline(self):
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endmarker = self._parsed.children[-1]
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# The newline is either in the endmarker as a prefix or the previous
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# leaf as a newline token.
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prefix = endmarker.prefix
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if prefix.endswith('\n'):
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endmarker.prefix = prefix = prefix[:-1]
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last_end = 0
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if '\n' not in prefix:
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# Basically if the last line doesn't end with a newline. we
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# have to add the previous line's end_position.
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previous_leaf = endmarker.get_previous_leaf()
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if previous_leaf is not None:
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last_end = previous_leaf.end_pos[1]
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last_line = re.sub('.*\n', '', prefix)
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endmarker.start_pos = endmarker.line - 1, last_end + len(last_line)
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else:
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newline = endmarker.get_previous_leaf()
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if newline is None:
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return # This means that the parser is empty.
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assert newline.value.endswith('\n')
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newline.value = newline.value[:-1]
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endmarker.start_pos = \
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newline.start_pos[0], newline.start_pos[1] + len(newline.value)
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class ParserWithRecovery(Parser):
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"""
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This class is used to parse a Python file, it then divides them into a
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class structure of different scopes.
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:param grammar: The grammar object of pgen2. Loaded by load_grammar.
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:param source: The codebase for the parser. Must be unicode.
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:param module_path: The path of the module in the file system, may be None.
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:type module_path: str
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"""
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def __init__(self, grammar, source, module_path=None, tokens=None,
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start_parsing=True):
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self.syntax_errors = []
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self._omit_dedent_list = []
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self._indent_counter = 0
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self._module_path = module_path
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# TODO do print absolute import detection here.
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# try:
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# del python_grammar_no_print_statement.keywords["print"]
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# except KeyError:
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# pass # Doesn't exist in the Python 3 grammar.
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# if self.options["print_function"]:
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# python_grammar = pygram.python_grammar_no_print_statement
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# else:
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super(ParserWithRecovery, self).__init__(
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grammar, source,
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tokens=tokens,
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start_parsing=start_parsing
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)
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def parse(self, tokenizer):
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root_node = super(ParserWithRecovery, self).parse(self._tokenize(tokenizer))
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self.module = root_node
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self.module.used_names = self._used_names
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self.module.path = self._module_path
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return root_node
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def error_recovery(self, grammar, stack, arcs, typ, value, start_pos, prefix,
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add_token_callback):
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"""
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This parser is written in a dynamic way, meaning that this parser
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allows using different grammars (even non-Python). However, error
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recovery is purely written for Python.
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"""
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def current_suite(stack):
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# For now just discard everything that is not a suite or
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# file_input, if we detect an error.
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for index, (dfa, state, (type_, nodes)) in reversed(list(enumerate(stack))):
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# `suite` can sometimes be only simple_stmt, not stmt.
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symbol = grammar.number2symbol[type_]
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if symbol == 'file_input':
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break
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elif symbol == 'suite' and len(nodes) > 1:
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# suites without an indent in them get discarded.
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break
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elif symbol == 'simple_stmt' and len(nodes) > 1:
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# simple_stmt can just be turned into a Node, if there are
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# enough statements. Ignore the rest after that.
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break
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return index, symbol, nodes
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index, symbol, nodes = current_suite(stack)
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if symbol == 'simple_stmt':
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index -= 2
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(_, _, (type_, suite_nodes)) = stack[index]
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symbol = grammar.number2symbol[type_]
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suite_nodes.append(pt.Node(symbol, list(nodes)))
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# Remove
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nodes[:] = []
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nodes = suite_nodes
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stack[index]
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# print('err', token.tok_name[typ], repr(value), start_pos, len(stack), index)
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if self._stack_removal(grammar, stack, arcs, index + 1, value, start_pos):
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add_token_callback(typ, value, start_pos, prefix)
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else:
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if typ == INDENT:
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# For every deleted INDENT we have to delete a DEDENT as well.
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# Otherwise the parser will get into trouble and DEDENT too early.
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self._omit_dedent_list.append(self._indent_counter)
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else:
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error_leaf = pt.ErrorLeaf(tok_name[typ].lower(), value, start_pos, prefix)
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stack[-1][2][1].append(error_leaf)
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def _stack_removal(self, grammar, stack, arcs, start_index, value, start_pos):
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failed_stack = []
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found = False
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all_nodes = []
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for dfa, state, (typ, nodes) in stack[start_index:]:
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if nodes:
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found = True
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if found:
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symbol = grammar.number2symbol[typ]
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failed_stack.append((symbol, nodes))
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all_nodes += nodes
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if failed_stack:
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stack[start_index - 1][2][1].append(pt.ErrorNode(all_nodes))
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stack[start_index:] = []
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return failed_stack
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def _tokenize(self, tokenizer):
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for typ, value, start_pos, prefix in tokenizer:
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# print(tokenize.tok_name[typ], repr(value), start_pos, repr(prefix))
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if typ == DEDENT:
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# We need to count indents, because if we just omit any DEDENT,
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# we might omit them in the wrong place.
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o = self._omit_dedent_list
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if o and o[-1] == self._indent_counter:
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o.pop()
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continue
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self._indent_counter -= 1
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elif typ == INDENT:
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self._indent_counter += 1
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yield typ, value, start_pos, prefix
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def __repr__(self):
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return "<%s: %s>" % (type(self).__name__, self.module)
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