X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/d5c95f6a8f274f42cce81bfe544266a7bb53474b..43b53a034c9e3ada9295bf7f93be473b66b74f75:/.vim/bundle/black/src/blib2to3/pgen2/parse.py diff --git a/.vim/bundle/black/src/blib2to3/pgen2/parse.py b/.vim/bundle/black/src/blib2to3/pgen2/parse.py deleted file mode 100644 index 47c8f02b..00000000 --- a/.vim/bundle/black/src/blib2to3/pgen2/parse.py +++ /dev/null @@ -1,235 +0,0 @@ -# Copyright 2004-2005 Elemental Security, Inc. All Rights Reserved. -# Licensed to PSF under a Contributor Agreement. - -"""Parser engine for the grammar tables generated by pgen. - -The grammar table must be loaded first. - -See Parser/parser.c in the Python distribution for additional info on -how this parsing engine works. - -""" - -# Local imports -from . import token -from typing import ( - Optional, - Text, - Union, - Tuple, - Dict, - List, - Callable, - Set, -) -from blib2to3.pgen2.grammar import Grammar -from blib2to3.pytree import NL, Context, RawNode, Leaf, Node - - -Results = Dict[Text, NL] -Convert = Callable[[Grammar, RawNode], Union[Node, Leaf]] -DFA = List[List[Tuple[int, int]]] -DFAS = Tuple[DFA, Dict[int, int]] - - -def lam_sub(grammar: Grammar, node: RawNode) -> NL: - assert node[3] is not None - return Node(type=node[0], children=node[3], context=node[2]) - - -class ParseError(Exception): - """Exception to signal the parser is stuck.""" - - def __init__( - self, msg: Text, type: Optional[int], value: Optional[Text], context: Context - ) -> None: - Exception.__init__( - self, "%s: type=%r, value=%r, context=%r" % (msg, type, value, context) - ) - self.msg = msg - self.type = type - self.value = value - self.context = context - - -class Parser(object): - """Parser engine. - - The proper usage sequence is: - - p = Parser(grammar, [converter]) # create instance - p.setup([start]) # prepare for parsing - : - if p.addtoken(...): # parse a token; may raise ParseError - break - root = p.rootnode # root of abstract syntax tree - - A Parser instance may be reused by calling setup() repeatedly. - - A Parser instance contains state pertaining to the current token - sequence, and should not be used concurrently by different threads - to parse separate token sequences. - - See driver.py for how to get input tokens by tokenizing a file or - string. - - Parsing is complete when addtoken() returns True; the root of the - abstract syntax tree can then be retrieved from the rootnode - instance variable. When a syntax error occurs, addtoken() raises - the ParseError exception. There is no error recovery; the parser - cannot be used after a syntax error was reported (but it can be - reinitialized by calling setup()). - - """ - - def __init__(self, grammar: Grammar, convert: Optional[Convert] = None) -> None: - """Constructor. - - The grammar argument is a grammar.Grammar instance; see the - grammar module for more information. - - The parser is not ready yet for parsing; you must call the - setup() method to get it started. - - The optional convert argument is a function mapping concrete - syntax tree nodes to abstract syntax tree nodes. If not - given, no conversion is done and the syntax tree produced is - the concrete syntax tree. If given, it must be a function of - two arguments, the first being the grammar (a grammar.Grammar - instance), and the second being the concrete syntax tree node - to be converted. The syntax tree is converted from the bottom - up. - - A concrete syntax tree node is a (type, value, context, nodes) - tuple, where type is the node type (a token or symbol number), - value is None for symbols and a string for tokens, context is - None or an opaque value used for error reporting (typically a - (lineno, offset) pair), and nodes is a list of children for - symbols, and None for tokens. - - An abstract syntax tree node may be anything; this is entirely - up to the converter function. - - """ - self.grammar = grammar - self.convert = convert or lam_sub - - def setup(self, start: Optional[int] = None) -> None: - """Prepare for parsing. - - This *must* be called before starting to parse. - - The optional argument is an alternative start symbol; it - defaults to the grammar's start symbol. - - You can use a Parser instance to parse any number of programs; - each time you call setup() the parser is reset to an initial - state determined by the (implicit or explicit) start symbol. - - """ - if start is None: - start = self.grammar.start - # Each stack entry is a tuple: (dfa, state, node). - # A node is a tuple: (type, value, context, children), - # where children is a list of nodes or None, and context may be None. - newnode: RawNode = (start, None, None, []) - stackentry = (self.grammar.dfas[start], 0, newnode) - self.stack: List[Tuple[DFAS, int, RawNode]] = [stackentry] - self.rootnode: Optional[NL] = None - self.used_names: Set[str] = set() - - def addtoken(self, type: int, value: Optional[Text], context: Context) -> bool: - """Add a token; return True iff this is the end of the program.""" - # Map from token to label - ilabel = self.classify(type, value, context) - # Loop until the token is shifted; may raise exceptions - while True: - dfa, state, node = self.stack[-1] - states, first = dfa - arcs = states[state] - # Look for a state with this label - for i, newstate in arcs: - t, v = self.grammar.labels[i] - if ilabel == i: - # Look it up in the list of labels - assert t < 256 - # Shift a token; we're done with it - self.shift(type, value, newstate, context) - # Pop while we are in an accept-only state - state = newstate - while states[state] == [(0, state)]: - self.pop() - if not self.stack: - # Done parsing! - return True - dfa, state, node = self.stack[-1] - states, first = dfa - # Done with this token - return False - elif t >= 256: - # See if it's a symbol and if we're in its first set - itsdfa = self.grammar.dfas[t] - itsstates, itsfirst = itsdfa - if ilabel in itsfirst: - # Push a symbol - self.push(t, self.grammar.dfas[t], newstate, context) - break # To continue the outer while loop - else: - if (0, state) in arcs: - # An accepting state, pop it and try something else - self.pop() - if not self.stack: - # Done parsing, but another token is input - raise ParseError("too much input", type, value, context) - else: - # No success finding a transition - raise ParseError("bad input", type, value, context) - - def classify(self, type: int, value: Optional[Text], context: Context) -> int: - """Turn a token into a label. (Internal)""" - if type == token.NAME: - # Keep a listing of all used names - assert value is not None - self.used_names.add(value) - # Check for reserved words - ilabel = self.grammar.keywords.get(value) - if ilabel is not None: - return ilabel - ilabel = self.grammar.tokens.get(type) - if ilabel is None: - raise ParseError("bad token", type, value, context) - return ilabel - - def shift( - self, type: int, value: Optional[Text], newstate: int, context: Context - ) -> None: - """Shift a token. (Internal)""" - dfa, state, node = self.stack[-1] - assert value is not None - assert context is not None - rawnode: RawNode = (type, value, context, None) - newnode = self.convert(self.grammar, rawnode) - if newnode is not None: - assert node[-1] is not None - node[-1].append(newnode) - self.stack[-1] = (dfa, newstate, node) - - def push(self, type: int, newdfa: DFAS, newstate: int, context: Context) -> None: - """Push a nonterminal. (Internal)""" - dfa, state, node = self.stack[-1] - newnode: RawNode = (type, None, context, []) - self.stack[-1] = (dfa, newstate, node) - self.stack.append((newdfa, 0, newnode)) - - def pop(self) -> None: - """Pop a nonterminal. (Internal)""" - popdfa, popstate, popnode = self.stack.pop() - newnode = self.convert(self.grammar, popnode) - if newnode is not None: - if self.stack: - dfa, state, node = self.stack[-1] - assert node[-1] is not None - node[-1].append(newnode) - else: - self.rootnode = newnode - self.rootnode.used_names = self.used_names