[Python-checkins] cpython: Issue #19655: Replace the ASDL parser carried with CPython
eli.bendersky
python-checkins at python.org
Sat May 10 02:58:22 CEST 2014
http://hg.python.org/cpython/rev/b769352e2922
changeset: 90610:b769352e2922
user: Eli Bendersky <eliben at gmail.com>
date: Fri May 09 17:58:22 2014 -0700
summary:
Issue #19655: Replace the ASDL parser carried with CPython
The new parser does not rely on Spark (which is now removed from our repo),
uses modern 3.x idioms and is significantly smaller and simpler.
It generates exactly the same AST files (.h and .c), so in practice no builds
should be affected.
files:
Misc/NEWS | 5 +
Parser/asdl.py | 572 ++++++++++-------------
Parser/asdl_c.py | 54 +-
Parser/spark.py | 849 -----------------------------------
4 files changed, 286 insertions(+), 1194 deletions(-)
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -57,6 +57,11 @@
- Issue #19995: %c, %o, %x, and %X now raise TypeError on non-integer input.
+- Issue #19655: The ASDL parser - used by the build process to generate code for
+ managing the Python AST in C - was rewritten. The new parser is self contained
+ and does not require to carry long the spark.py parser-generator library;
+ spark.py was removed from the source base.
+
- Issue #12546: Allow \x00 to be used as a fill character when using str, int,
float, and complex __format__ methods.
diff --git a/Parser/asdl.py b/Parser/asdl.py
--- a/Parser/asdl.py
+++ b/Parser/asdl.py
@@ -1,255 +1,53 @@
-"""An implementation of the Zephyr Abstract Syntax Definition Language.
+#-------------------------------------------------------------------------------
+# Parser for ASDL [1] definition files. Reads in an ASDL description and parses
+# it into an AST that describes it.
+#
+# The EBNF we're parsing here: Figure 1 of the paper [1]. Extended to support
+# modules and attributes after a product. Words starting with Capital letters
+# are terminals. Literal tokens are in "double quotes". Others are
+# non-terminals. Id is either TokenId or ConstructorId.
+#
+# module ::= "module" Id "{" [definitions] "}"
+# definitions ::= { TypeId "=" type }
+# type ::= product | sum
+# product ::= fields ["attributes" fields]
+# fields ::= "(" { field, "," } field ")"
+# field ::= TypeId ["?" | "*"] [Id]
+# sum ::= constructor { "|" constructor } ["attributes" fields]
+# constructor ::= ConstructorId [fields]
+#
+# [1] "The Zephyr Abstract Syntax Description Language" by Wang, et. al. See
+# http://asdl.sourceforge.net/
+#-------------------------------------------------------------------------------
+from collections import namedtuple
+import re
-See http://asdl.sourceforge.net/ and
-http://www.cs.princeton.edu/research/techreps/TR-554-97
+__all__ = [
+ 'builtin_types', 'parse', 'AST', 'Module', 'Type', 'Constructor',
+ 'Field', 'Sum', 'Product', 'VisitorBase', 'Check', 'check']
-Only supports top level module decl, not view. I'm guessing that view
-is intended to support the browser and I'm not interested in the
-browser.
+# The following classes define nodes into which the ASDL description is parsed.
+# Note: this is a "meta-AST". ASDL files (such as Python.asdl) describe the AST
+# structure used by a programming language. But ASDL files themselves need to be
+# parsed. This module parses ASDL files and uses a simple AST to represent them.
+# See the EBNF at the top of the file to understand the logical connection
+# between the various node types.
-Changes for Python: Add support for module versions
-"""
+builtin_types = set(
+ ['identifier', 'string', 'bytes', 'int', 'object', 'singleton'])
-import os
-import sys
-import traceback
-
-import spark
-
-def output(*strings):
- for s in strings:
- sys.stdout.write(str(s) + "\n")
-
-
-class Token(object):
- # spark seems to dispatch in the parser based on a token's
- # type attribute
- def __init__(self, type, lineno):
- self.type = type
- self.lineno = lineno
-
- def __str__(self):
- return self.type
-
+class AST:
def __repr__(self):
- return str(self)
-
-class Id(Token):
- def __init__(self, value, lineno):
- self.type = 'Id'
- self.value = value
- self.lineno = lineno
-
- def __str__(self):
- return self.value
-
-class String(Token):
- def __init__(self, value, lineno):
- self.type = 'String'
- self.value = value
- self.lineno = lineno
-
-class ASDLSyntaxError(Exception):
-
- def __init__(self, lineno, token=None, msg=None):
- self.lineno = lineno
- self.token = token
- self.msg = msg
-
- def __str__(self):
- if self.msg is None:
- return "Error at '%s', line %d" % (self.token, self.lineno)
- else:
- return "%s, line %d" % (self.msg, self.lineno)
-
-class ASDLScanner(spark.GenericScanner, object):
-
- def tokenize(self, input):
- self.rv = []
- self.lineno = 1
- super(ASDLScanner, self).tokenize(input)
- return self.rv
-
- def t_id(self, s):
- r"[\w\.]+"
- # XXX doesn't distinguish upper vs. lower, which is
- # significant for ASDL.
- self.rv.append(Id(s, self.lineno))
-
- def t_string(self, s):
- r'"[^"]*"'
- self.rv.append(String(s, self.lineno))
-
- def t_xxx(self, s): # not sure what this production means
- r"<="
- self.rv.append(Token(s, self.lineno))
-
- def t_punctuation(self, s):
- r"[\{\}\*\=\|\(\)\,\?\:]"
- self.rv.append(Token(s, self.lineno))
-
- def t_comment(self, s):
- r"\-\-[^\n]*"
- pass
-
- def t_newline(self, s):
- r"\n"
- self.lineno += 1
-
- def t_whitespace(self, s):
- r"[ \t]+"
- pass
-
- def t_default(self, s):
- r" . +"
- raise ValueError("unmatched input: %r" % s)
-
-class ASDLParser(spark.GenericParser, object):
- def __init__(self):
- super(ASDLParser, self).__init__("module")
-
- def typestring(self, tok):
- return tok.type
-
- def error(self, tok):
- raise ASDLSyntaxError(tok.lineno, tok)
-
- def p_module_0(self, info):
- " module ::= Id Id { } "
- module, name, _0, _1 = info
- if module.value != "module":
- raise ASDLSyntaxError(module.lineno,
- msg="expected 'module', found %s" % module)
- return Module(name, None)
-
- def p_module(self, info):
- " module ::= Id Id { definitions } "
- module, name, _0, definitions, _1 = info
- if module.value != "module":
- raise ASDLSyntaxError(module.lineno,
- msg="expected 'module', found %s" % module)
- return Module(name, definitions)
-
- def p_definition_0(self, definition):
- " definitions ::= definition "
- return definition[0]
-
- def p_definition_1(self, definitions):
- " definitions ::= definition definitions "
- return definitions[0] + definitions[1]
-
- def p_definition(self, info):
- " definition ::= Id = type "
- id, _, type = info
- return [Type(id, type)]
-
- def p_type_0(self, product):
- " type ::= product "
- return product[0]
-
- def p_type_1(self, sum):
- " type ::= sum "
- return Sum(sum[0])
-
- def p_type_2(self, info):
- " type ::= sum Id ( fields ) "
- sum, id, _0, attributes, _1 = info
- if id.value != "attributes":
- raise ASDLSyntaxError(id.lineno,
- msg="expected attributes, found %s" % id)
- return Sum(sum, attributes)
-
- def p_product_0(self, info):
- " product ::= ( fields ) "
- _0, fields, _1 = info
- return Product(fields)
-
- def p_product_1(self, info):
- " product ::= ( fields ) Id ( fields ) "
- _0, fields, _1, id, _2, attributes, _3 = info
- if id.value != "attributes":
- raise ASDLSyntaxError(id.lineno,
- msg="expected attributes, found %s" % id)
- return Product(fields, attributes)
-
- def p_sum_0(self, constructor):
- " sum ::= constructor "
- return [constructor[0]]
-
- def p_sum_1(self, info):
- " sum ::= constructor | sum "
- constructor, _, sum = info
- return [constructor] + sum
-
- def p_sum_2(self, info):
- " sum ::= constructor | sum "
- constructor, _, sum = info
- return [constructor] + sum
-
- def p_constructor_0(self, id):
- " constructor ::= Id "
- return Constructor(id[0])
-
- def p_constructor_1(self, info):
- " constructor ::= Id ( fields ) "
- id, _0, fields, _1 = info
- return Constructor(id, fields)
-
- def p_fields_0(self, field):
- " fields ::= field "
- return [field[0]]
-
- def p_fields_1(self, info):
- " fields ::= fields , field "
- fields, _, field = info
- return fields + [field]
-
- def p_field_0(self, type_):
- " field ::= Id "
- return Field(type_[0])
-
- def p_field_1(self, info):
- " field ::= Id Id "
- type, name = info
- return Field(type, name)
-
- def p_field_2(self, info):
- " field ::= Id * Id "
- type, _, name = info
- return Field(type, name, seq=True)
-
- def p_field_3(self, info):
- " field ::= Id ? Id "
- type, _, name = info
- return Field(type, name, opt=True)
-
- def p_field_4(self, type_):
- " field ::= Id * "
- return Field(type_[0], seq=True)
-
- def p_field_5(self, type_):
- " field ::= Id ? "
- return Field(type[0], opt=True)
-
-builtin_types = ("identifier", "string", "bytes", "int", "object", "singleton")
-
-# below is a collection of classes to capture the AST of an AST :-)
-# not sure if any of the methods are useful yet, but I'm adding them
-# piecemeal as they seem helpful
-
-class AST(object):
- pass # a marker class
+ raise NotImplementedError
class Module(AST):
def __init__(self, name, dfns):
self.name = name
self.dfns = dfns
- self.types = {} # maps type name to value (from dfns)
- for type in dfns:
- self.types[type.name.value] = type.value
+ self.types = {type.name: type.value for type in dfns}
def __repr__(self):
- return "Module(%s, %s)" % (self.name, self.dfns)
+ return 'Module({0.name}, {0.dfns})'.format(self)
class Type(AST):
def __init__(self, name, value):
@@ -257,7 +55,7 @@
self.value = value
def __repr__(self):
- return "Type(%s, %s)" % (self.name, self.value)
+ return 'Type({0.name}, {0.value})'.format(self)
class Constructor(AST):
def __init__(self, name, fields=None):
@@ -265,7 +63,7 @@
self.fields = fields or []
def __repr__(self):
- return "Constructor(%s, %s)" % (self.name, self.fields)
+ return 'Constructor({0.name}, {0.fields})'.format(self)
class Field(AST):
def __init__(self, type, name=None, seq=False, opt=False):
@@ -282,9 +80,9 @@
else:
extra = ""
if self.name is None:
- return "Field(%s%s)" % (self.type, extra)
+ return 'Field({0.type}{1})'.format(self, extra)
else:
- return "Field(%s, %s%s)" % (self.type, self.name, extra)
+ return 'Field({0.type}, {0.name}{1})'.format(self, extra)
class Sum(AST):
def __init__(self, types, attributes=None):
@@ -292,10 +90,10 @@
self.attributes = attributes or []
def __repr__(self):
- if self.attributes is None:
- return "Sum(%s)" % self.types
+ if self.attributes:
+ return 'Sum({0.types}, {0.attributes})'.format(self)
else:
- return "Sum(%s, %s)" % (self.types, self.attributes)
+ return 'Sum({0.types})'.format(self)
class Product(AST):
def __init__(self, fields, attributes=None):
@@ -303,49 +101,43 @@
self.attributes = attributes or []
def __repr__(self):
- if self.attributes is None:
- return "Product(%s)" % self.fields
+ if self.attributes:
+ return 'Product({0.fields}, {0.attributes})'.format(self)
else:
- return "Product(%s, %s)" % (self.fields, self.attributes)
+ return 'Product({0.fields})'.format(self)
-class VisitorBase(object):
+# A generic visitor for the meta-AST that describes ASDL. This can be used by
+# emitters. Note that this visitor does not provide a generic visit method, so a
+# subclass needs to define visit methods from visitModule to as deep as the
+# interesting node.
+# We also define a Check visitor that makes sure the parsed ASDL is well-formed.
- def __init__(self, skip=False):
+class VisitorBase:
+ """Generic tree visitor for ASTs."""
+ def __init__(self):
self.cache = {}
- self.skip = skip
- def visit(self, object, *args):
- meth = self._dispatch(object)
- if meth is None:
- return
- try:
- meth(object, *args)
- except Exception:
- output("Error visiting" + repr(object))
- output(str(sys.exc_info()[1]))
- traceback.print_exc()
- # XXX hack
- if hasattr(self, 'file'):
- self.file.flush()
- os._exit(1)
-
- def _dispatch(self, object):
- assert isinstance(object, AST), repr(object)
- klass = object.__class__
+ def visit(self, obj, *args):
+ klass = obj.__class__
meth = self.cache.get(klass)
if meth is None:
methname = "visit" + klass.__name__
- if self.skip:
- meth = getattr(self, methname, None)
- else:
- meth = getattr(self, methname)
+ meth = getattr(self, methname, None)
self.cache[klass] = meth
- return meth
+ if meth:
+ try:
+ meth(obj, *args)
+ except Exception as e:
+ print("Error visiting %r: %s" % (obj, e))
+ raise
class Check(VisitorBase):
+ """A visitor that checks a parsed ASDL tree for correctness.
+ Errors are printed and accumulated.
+ """
def __init__(self):
- super(Check, self).__init__(skip=True)
+ super().__init__()
self.cons = {}
self.errors = 0
self.types = {}
@@ -367,8 +159,8 @@
if conflict is None:
self.cons[key] = name
else:
- output("Redefinition of constructor %s" % key)
- output("Defined in %s and %s" % (conflict, name))
+ print('Redefinition of constructor {}'.format(key))
+ print('Defined in {} and {}'.format(conflict, name))
self.errors += 1
for f in cons.fields:
self.visit(f, key)
@@ -383,6 +175,11 @@
self.visit(f, name)
def check(mod):
+ """Check the parsed ASDL tree for correctness.
+
+ Return True if success. For failure, the errors are printed out and False
+ is returned.
+ """
v = Check()
v.visit(mod)
@@ -390,47 +187,190 @@
if t not in mod.types and not t in builtin_types:
v.errors += 1
uses = ", ".join(v.types[t])
- output("Undefined type %s, used in %s" % (t, uses))
-
+ print('Undefined type {}, used in {}'.format(t, uses))
return not v.errors
-def parse(file):
- scanner = ASDLScanner()
- parser = ASDLParser()
+# The ASDL parser itself comes next. The only interesting external interface
+# here is the top-level parse function.
- f = open(file)
- try:
- buf = f.read()
- finally:
- f.close()
- tokens = scanner.tokenize(buf)
- try:
- return parser.parse(tokens)
- except ASDLSyntaxError:
- err = sys.exc_info()[1]
- output(str(err))
- lines = buf.split("\n")
- output(lines[err.lineno - 1]) # lines starts at 0, files at 1
+def parse(filename):
+ """Parse ASDL from the given file and return a Module node describing it."""
+ with open(filename) as f:
+ parser = ASDLParser()
+ return parser.parse(f.read())
-if __name__ == "__main__":
- import glob
- import sys
+# Types for describing tokens in an ASDL specification.
+class TokenKind:
+ """TokenKind is provides a scope for enumerated token kinds."""
+ (ConstructorId, TypeId, Equals, Comma, Question, Pipe, Asterisk,
+ LParen, RParen, LBrace, RBrace) = range(11)
- if len(sys.argv) > 1:
- files = sys.argv[1:]
- else:
- testdir = "tests"
- files = glob.glob(testdir + "/*.asdl")
+ operator_table = {
+ '=': Equals, ',': Comma, '?': Question, '|': Pipe, '(': LParen,
+ ')': RParen, '*': Asterisk, '{': LBrace, '}': RBrace}
- for file in files:
- output(file)
- mod = parse(file)
- if not mod:
- break
- output("module", mod.name)
- output(len(mod.dfns), "definitions")
- if not check(mod):
- output("Check failed")
+Token = namedtuple('Token', 'kind value lineno')
+
+class ASDLSyntaxError(Exception):
+ def __init__(self, msg, lineno=None):
+ self.msg = msg
+ self.lineno = lineno or '<unknown>'
+
+ def __str__(self):
+ return 'Syntax error on line {0.lineno}: {0.msg}'.format(self)
+
+def tokenize_asdl(buf):
+ """Tokenize the given buffer. Yield Token objects."""
+ for lineno, line in enumerate(buf.splitlines(), 1):
+ for m in re.finditer(r'\s*(\w+|--.*|.)', line.strip()):
+ c = m.group(1)
+ if c[0].isalpha():
+ # Some kind of identifier
+ if c[0].isupper():
+ yield Token(TokenKind.ConstructorId, c, lineno)
+ else:
+ yield Token(TokenKind.TypeId, c, lineno)
+ elif c[:2] == '--':
+ # Comment
+ break
+ else:
+ # Operators
+ try:
+ op_kind = TokenKind.operator_table[c]
+ except KeyError:
+ raise ASDLSyntaxError('Invalid operator %s' % c, lineno)
+ yield Token(op_kind, c, lineno)
+
+class ASDLParser:
+ """Parser for ASDL files.
+
+ Create, then call the parse method on a buffer containing ASDL.
+ This is a simple recursive descent parser that uses tokenize_asdl for the
+ lexing.
+ """
+ def __init__(self):
+ self._tokenizer = None
+ self.cur_token = None
+
+ def parse(self, buf):
+ """Parse the ASDL in the buffer and return an AST with a Module root.
+ """
+ self._tokenizer = tokenize_asdl(buf)
+ self._advance()
+ return self._parse_module()
+
+ def _parse_module(self):
+ if self._at_keyword('module'):
+ self._advance()
else:
- for dfn in mod.dfns:
- output(dfn.name, dfn.value)
+ raise ASDLSyntaxError(
+ 'Expected "module" (found {})'.format(self.cur_token.value),
+ self.cur_token.lineno)
+ name = self._match(self._id_kinds)
+ self._match(TokenKind.LBrace)
+ defs = self._parse_definitions()
+ self._match(TokenKind.RBrace)
+ return Module(name, defs)
+
+ def _parse_definitions(self):
+ defs = []
+ while self.cur_token.kind == TokenKind.TypeId:
+ typename = self._advance()
+ self._match(TokenKind.Equals)
+ type = self._parse_type()
+ defs.append(Type(typename, type))
+ return defs
+
+ def _parse_type(self):
+ if self.cur_token.kind == TokenKind.LParen:
+ # If we see a (, it's a product
+ return self._parse_product()
+ else:
+ # Otherwise it's a sum. Look for ConstructorId
+ sumlist = [Constructor(self._match(TokenKind.ConstructorId),
+ self._parse_optional_fields())]
+ while self.cur_token.kind == TokenKind.Pipe:
+ # More constructors
+ self._advance()
+ sumlist.append(Constructor(
+ self._match(TokenKind.ConstructorId),
+ self._parse_optional_fields()))
+ return Sum(sumlist, self._parse_optional_attributes())
+
+ def _parse_product(self):
+ return Product(self._parse_fields(), self._parse_optional_attributes())
+
+ def _parse_fields(self):
+ fields = []
+ self._match(TokenKind.LParen)
+ while self.cur_token.kind == TokenKind.TypeId:
+ typename = self._advance()
+ is_seq, is_opt = self._parse_optional_field_quantifier()
+ id = (self._advance() if self.cur_token.kind in self._id_kinds
+ else None)
+ fields.append(Field(typename, id, seq=is_seq, opt=is_opt))
+ if self.cur_token.kind == TokenKind.RParen:
+ break
+ elif self.cur_token.kind == TokenKind.Comma:
+ self._advance()
+ self._match(TokenKind.RParen)
+ return fields
+
+ def _parse_optional_fields(self):
+ if self.cur_token.kind == TokenKind.LParen:
+ return self._parse_fields()
+ else:
+ return None
+
+ def _parse_optional_attributes(self):
+ if self._at_keyword('attributes'):
+ self._advance()
+ return self._parse_fields()
+ else:
+ return None
+
+ def _parse_optional_field_quantifier(self):
+ is_seq, is_opt = False, False
+ if self.cur_token.kind == TokenKind.Asterisk:
+ is_seq = True
+ self._advance()
+ elif self.cur_token.kind == TokenKind.Question:
+ is_opt = True
+ self._advance()
+ return is_seq, is_opt
+
+ def _advance(self):
+ """ Return the value of the current token and read the next one into
+ self.cur_token.
+ """
+ cur_val = None if self.cur_token is None else self.cur_token.value
+ try:
+ self.cur_token = next(self._tokenizer)
+ except StopIteration:
+ self.cur_token = None
+ return cur_val
+
+ _id_kinds = (TokenKind.ConstructorId, TokenKind.TypeId)
+
+ def _match(self, kind):
+ """The 'match' primitive of RD parsers.
+
+ * Verifies that the current token is of the given kind (kind can
+ be a tuple, in which the kind must match one of its members).
+ * Returns the value of the current token
+ * Reads in the next token
+ """
+ if (isinstance(kind, tuple) and self.cur_token.kind in kind or
+ self.cur_token.kind == kind
+ ):
+ value = self.cur_token.value
+ self._advance()
+ return value
+ else:
+ raise ASDLSyntaxError(
+ 'Unmatched {} (found {})'.format(kind, self.cur_token.kind),
+ self.cur_token.lineno)
+
+ def _at_keyword(self, keyword):
+ return (self.cur_token.kind == TokenKind.TypeId and
+ self.cur_token.value == keyword)
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -1,9 +1,6 @@
#! /usr/bin/env python
"""Generate C code from an ASDL description."""
-# TO DO
-# handle fields that have a type but no name
-
import os, sys
import asdl
@@ -14,12 +11,8 @@
def get_c_type(name):
"""Return a string for the C name of the type.
- This function special cases the default types provided by asdl:
- identifier, string, int.
+ This function special cases the default types provided by asdl.
"""
- # XXX ack! need to figure out where Id is useful and where string
- if isinstance(name, asdl.Id):
- name = name.value
if name in asdl.builtin_types:
return name
else:
@@ -144,7 +137,7 @@
class StructVisitor(EmitVisitor):
- """Visitor to generate typdefs for AST."""
+ """Visitor to generate typedefs for AST."""
def visitModule(self, mod):
for dfn in mod.dfns:
@@ -188,9 +181,6 @@
self.visit(f, depth + 1)
self.emit("} %s;" % cons.name, depth)
self.emit("", depth)
- else:
- # XXX not sure what I want here, nothing is probably fine
- pass
def visitField(self, field, depth):
# XXX need to lookup field.type, because it might be something
@@ -198,7 +188,7 @@
ctype = get_c_type(field.type)
name = field.name
if field.seq:
- if field.type.value in ('cmpop',):
+ if field.type == 'cmpop':
self.emit("asdl_int_seq *%(name)s;" % locals(), depth)
else:
self.emit("asdl_seq *%(name)s;" % locals(), depth)
@@ -253,7 +243,7 @@
name = f.name
# XXX should extend get_c_type() to handle this
if f.seq:
- if f.type.value in ('cmpop',):
+ if f.type == 'cmpop':
ctype = "asdl_int_seq *"
else:
ctype = "asdl_seq *"
@@ -437,7 +427,7 @@
self.emit("", 0)
for f in t.fields:
self.visitField(f, t.name, sum=sum, depth=2)
- args = [f.name.value for f in t.fields] + [a.name.value for a in sum.attributes]
+ args = [f.name for f in t.fields] + [a.name for a in sum.attributes]
self.emit("*out = %s(%s);" % (t.name, self.buildArgs(args)), 2)
self.emit("if (*out == NULL) goto failed;", 2)
self.emit("return 0;", 2)
@@ -465,7 +455,7 @@
self.emit("", 0)
for f in prod.fields:
self.visitField(f, name, prod=prod, depth=1)
- args = [f.name.value for f in prod.fields]
+ args = [f.name for f in prod.fields]
self.emit("*out = %s(%s);" % (name, self.buildArgs(args)), 1)
self.emit("return 0;", 1)
self.emit("failed:", 0)
@@ -487,8 +477,8 @@
def isSimpleSum(self, field):
# XXX can the members of this list be determined automatically?
- return field.type.value in ('expr_context', 'boolop', 'operator',
- 'unaryop', 'cmpop')
+ return field.type in ('expr_context', 'boolop', 'operator',
+ 'unaryop', 'cmpop')
def isNumeric(self, field):
return get_c_type(field.type) in ("int", "bool")
@@ -960,7 +950,7 @@
def visitProduct(self, prod, name):
if prod.fields:
- fields = name.value+"_fields"
+ fields = name+"_fields"
else:
fields = "NULL"
self.emit('%s_type = make_type("%s", &AST_type, %s, %d);' %
@@ -987,7 +977,7 @@
def visitConstructor(self, cons, name, simple):
if cons.fields:
- fields = cons.name.value+"_fields"
+ fields = cons.name+"_fields"
else:
fields = "NULL"
self.emit('%s_type = make_type("%s", %s_type, %s, %d);' %
@@ -1170,7 +1160,7 @@
def set(self, field, value, depth):
if field.seq:
# XXX should really check for is_simple, but that requires a symbol table
- if field.type.value == "cmpop":
+ if field.type == "cmpop":
# While the sequence elements are stored as void*,
# ast2obj_cmpop expects an enum
self.emit("{", depth)
@@ -1249,12 +1239,15 @@
common_msg = "/* File automatically generated by %s. */\n\n"
-def main(srcfile):
+def main(srcfile, dump_module=False):
argv0 = sys.argv[0]
components = argv0.split(os.sep)
argv0 = os.sep.join(components[-2:])
auto_gen_msg = common_msg % argv0
mod = asdl.parse(srcfile)
+ if dump_module:
+ print('Parsed Module:')
+ print(mod)
if not asdl.check(mod):
sys.exit(1)
if INC_DIR:
@@ -1301,16 +1294,19 @@
INC_DIR = ''
SRC_DIR = ''
- opts, args = getopt.getopt(sys.argv[1:], "h:c:")
- if len(opts) != 1:
- sys.stdout.write("Must specify exactly one output file\n")
- sys.exit(1)
+ dump_module = False
+ opts, args = getopt.getopt(sys.argv[1:], "dh:c:")
for o, v in opts:
if o == '-h':
INC_DIR = v
if o == '-c':
SRC_DIR = v
- if len(args) != 1:
- sys.stdout.write("Must specify single input file\n")
+ if o == '-d':
+ dump_module = True
+ if INC_DIR and SRC_DIR:
+ print('Must specify exactly one output file')
sys.exit(1)
- main(args[0])
+ elif len(args) != 1:
+ print('Must specify single input file')
+ sys.exit(1)
+ main(args[0], dump_module)
diff --git a/Parser/spark.py b/Parser/spark.py
deleted file mode 100644
--- a/Parser/spark.py
+++ /dev/null
@@ -1,849 +0,0 @@
-# Copyright (c) 1998-2002 John Aycock
-#
-# Permission is hereby granted, free of charge, to any person obtaining
-# a copy of this software and associated documentation files (the
-# "Software"), to deal in the Software without restriction, including
-# without limitation the rights to use, copy, modify, merge, publish,
-# distribute, sublicense, and/or sell copies of the Software, and to
-# permit persons to whom the Software is furnished to do so, subject to
-# the following conditions:
-#
-# The above copyright notice and this permission notice shall be
-# included in all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-__version__ = 'SPARK-0.7 (pre-alpha-5)'
-
-import re
-
-# Compatibility with older pythons.
-def output(string='', end='\n'):
- sys.stdout.write(string + end)
-
-try:
- sorted
-except NameError:
- def sorted(seq):
- seq2 = seq[:]
- seq2.sort()
- return seq2
-
-def _namelist(instance):
- namelist, namedict, classlist = [], {}, [instance.__class__]
- for c in classlist:
- for b in c.__bases__:
- classlist.append(b)
- for name in c.__dict__.keys():
- if name not in namedict:
- namelist.append(name)
- namedict[name] = 1
- return namelist
-
-class GenericScanner:
- def __init__(self, flags=0):
- pattern = self.reflect()
- self.re = re.compile(pattern, re.VERBOSE|flags)
-
- self.index2func = {}
- for name, number in self.re.groupindex.items():
- self.index2func[number-1] = getattr(self, 't_' + name)
-
- def makeRE(self, name):
- doc = getattr(self, name).__doc__
- rv = '(?P<%s>%s)' % (name[2:], doc)
- return rv
-
- def reflect(self):
- rv = []
- for name in _namelist(self):
- if name[:2] == 't_' and name != 't_default':
- rv.append(self.makeRE(name))
-
- rv.append(self.makeRE('t_default'))
- return '|'.join(rv)
-
- def error(self, s, pos):
- output("Lexical error at position %s" % pos)
- raise SystemExit
-
- def tokenize(self, s):
- pos = 0
- n = len(s)
- while pos < n:
- m = self.re.match(s, pos)
- if m is None:
- self.error(s, pos)
-
- groups = m.groups()
- for i in range(len(groups)):
- if groups[i] and i in self.index2func:
- self.index2func[i](groups[i])
- pos = m.end()
-
- def t_default(self, s):
- r'( . | \n )+'
- output("Specification error: unmatched input")
- raise SystemExit
-
-#
-# Extracted from GenericParser and made global so that [un]picking works.
-#
-class _State:
- def __init__(self, stateno, items):
- self.T, self.complete, self.items = [], [], items
- self.stateno = stateno
-
-class GenericParser:
- #
- # An Earley parser, as per J. Earley, "An Efficient Context-Free
- # Parsing Algorithm", CACM 13(2), pp. 94-102. Also J. C. Earley,
- # "An Efficient Context-Free Parsing Algorithm", Ph.D. thesis,
- # Carnegie-Mellon University, August 1968. New formulation of
- # the parser according to J. Aycock, "Practical Earley Parsing
- # and the SPARK Toolkit", Ph.D. thesis, University of Victoria,
- # 2001, and J. Aycock and R. N. Horspool, "Practical Earley
- # Parsing", unpublished paper, 2001.
- #
-
- def __init__(self, start):
- self.rules = {}
- self.rule2func = {}
- self.rule2name = {}
- self.collectRules()
- self.augment(start)
- self.ruleschanged = 1
-
- _NULLABLE = '\e_'
- _START = 'START'
- _BOF = '|-'
-
- #
- # When pickling, take the time to generate the full state machine;
- # some information is then extraneous, too. Unfortunately we
- # can't save the rule2func map.
- #
- def __getstate__(self):
- if self.ruleschanged:
- #
- # XXX - duplicated from parse()
- #
- self.computeNull()
- self.newrules = {}
- self.new2old = {}
- self.makeNewRules()
- self.ruleschanged = 0
- self.edges, self.cores = {}, {}
- self.states = { 0: self.makeState0() }
- self.makeState(0, self._BOF)
- #
- # XXX - should find a better way to do this..
- #
- changes = 1
- while changes:
- changes = 0
- for k, v in self.edges.items():
- if v is None:
- state, sym = k
- if state in self.states:
- self.goto(state, sym)
- changes = 1
- rv = self.__dict__.copy()
- for s in self.states.values():
- del s.items
- del rv['rule2func']
- del rv['nullable']
- del rv['cores']
- return rv
-
- def __setstate__(self, D):
- self.rules = {}
- self.rule2func = {}
- self.rule2name = {}
- self.collectRules()
- start = D['rules'][self._START][0][1][1] # Blech.
- self.augment(start)
- D['rule2func'] = self.rule2func
- D['makeSet'] = self.makeSet_fast
- self.__dict__ = D
-
- #
- # A hook for GenericASTBuilder and GenericASTMatcher. Mess
- # thee not with this; nor shall thee toucheth the _preprocess
- # argument to addRule.
- #
- def preprocess(self, rule, func): return rule, func
-
- def addRule(self, doc, func, _preprocess=1):
- fn = func
- rules = doc.split()
-
- index = []
- for i in range(len(rules)):
- if rules[i] == '::=':
- index.append(i-1)
- index.append(len(rules))
-
- for i in range(len(index)-1):
- lhs = rules[index[i]]
- rhs = rules[index[i]+2:index[i+1]]
- rule = (lhs, tuple(rhs))
-
- if _preprocess:
- rule, fn = self.preprocess(rule, func)
-
- if lhs in self.rules:
- self.rules[lhs].append(rule)
- else:
- self.rules[lhs] = [ rule ]
- self.rule2func[rule] = fn
- self.rule2name[rule] = func.__name__[2:]
- self.ruleschanged = 1
-
- def collectRules(self):
- for name in _namelist(self):
- if name[:2] == 'p_':
- func = getattr(self, name)
- doc = func.__doc__
- self.addRule(doc, func)
-
- def augment(self, start):
- rule = '%s ::= %s %s' % (self._START, self._BOF, start)
- self.addRule(rule, lambda args: args[1], 0)
-
- def computeNull(self):
- self.nullable = {}
- tbd = []
-
- for rulelist in self.rules.values():
- lhs = rulelist[0][0]
- self.nullable[lhs] = 0
- for rule in rulelist:
- rhs = rule[1]
- if len(rhs) == 0:
- self.nullable[lhs] = 1
- continue
- #
- # We only need to consider rules which
- # consist entirely of nonterminal symbols.
- # This should be a savings on typical
- # grammars.
- #
- for sym in rhs:
- if sym not in self.rules:
- break
- else:
- tbd.append(rule)
- changes = 1
- while changes:
- changes = 0
- for lhs, rhs in tbd:
- if self.nullable[lhs]:
- continue
- for sym in rhs:
- if not self.nullable[sym]:
- break
- else:
- self.nullable[lhs] = 1
- changes = 1
-
- def makeState0(self):
- s0 = _State(0, [])
- for rule in self.newrules[self._START]:
- s0.items.append((rule, 0))
- return s0
-
- def finalState(self, tokens):
- #
- # Yuck.
- #
- if len(self.newrules[self._START]) == 2 and len(tokens) == 0:
- return 1
- start = self.rules[self._START][0][1][1]
- return self.goto(1, start)
-
- def makeNewRules(self):
- worklist = []
- for rulelist in self.rules.values():
- for rule in rulelist:
- worklist.append((rule, 0, 1, rule))
-
- for rule, i, candidate, oldrule in worklist:
- lhs, rhs = rule
- n = len(rhs)
- while i < n:
- sym = rhs[i]
- if sym not in self.rules or \
- not self.nullable[sym]:
- candidate = 0
- i = i + 1
- continue
-
- newrhs = list(rhs)
- newrhs[i] = self._NULLABLE+sym
- newrule = (lhs, tuple(newrhs))
- worklist.append((newrule, i+1,
- candidate, oldrule))
- candidate = 0
- i = i + 1
- else:
- if candidate:
- lhs = self._NULLABLE+lhs
- rule = (lhs, rhs)
- if lhs in self.newrules:
- self.newrules[lhs].append(rule)
- else:
- self.newrules[lhs] = [ rule ]
- self.new2old[rule] = oldrule
-
- def typestring(self, token):
- return None
-
- def error(self, token):
- output("Syntax error at or near `%s' token" % token)
- raise SystemExit
-
- def parse(self, tokens):
- sets = [ [(1,0), (2,0)] ]
- self.links = {}
-
- if self.ruleschanged:
- self.computeNull()
- self.newrules = {}
- self.new2old = {}
- self.makeNewRules()
- self.ruleschanged = 0
- self.edges, self.cores = {}, {}
- self.states = { 0: self.makeState0() }
- self.makeState(0, self._BOF)
-
- for i in range(len(tokens)):
- sets.append([])
-
- if sets[i] == []:
- break
- self.makeSet(tokens[i], sets, i)
- else:
- sets.append([])
- self.makeSet(None, sets, len(tokens))
-
- #_dump(tokens, sets, self.states)
-
- finalitem = (self.finalState(tokens), 0)
- if finalitem not in sets[-2]:
- if len(tokens) > 0:
- self.error(tokens[i-1])
- else:
- self.error(None)
-
- return self.buildTree(self._START, finalitem,
- tokens, len(sets)-2)
-
- def isnullable(self, sym):
- #
- # For symbols in G_e only. If we weren't supporting 1.5,
- # could just use sym.startswith().
- #
- return self._NULLABLE == sym[0:len(self._NULLABLE)]
-
- def skip(self, hs, pos=0):
- n = len(hs[1])
- while pos < n:
- if not self.isnullable(hs[1][pos]):
- break
- pos = pos + 1
- return pos
-
- def makeState(self, state, sym):
- assert sym is not None
- #
- # Compute \epsilon-kernel state's core and see if
- # it exists already.
- #
- kitems = []
- for rule, pos in self.states[state].items:
- lhs, rhs = rule
- if rhs[pos:pos+1] == (sym,):
- kitems.append((rule, self.skip(rule, pos+1)))
- core = kitems
-
- core.sort()
- tcore = tuple(core)
- if tcore in self.cores:
- return self.cores[tcore]
- #
- # Nope, doesn't exist. Compute it and the associated
- # \epsilon-nonkernel state together; we'll need it right away.
- #
- k = self.cores[tcore] = len(self.states)
- K, NK = _State(k, kitems), _State(k+1, [])
- self.states[k] = K
- predicted = {}
-
- edges = self.edges
- rules = self.newrules
- for X in K, NK:
- worklist = X.items
- for item in worklist:
- rule, pos = item
- lhs, rhs = rule
- if pos == len(rhs):
- X.complete.append(rule)
- continue
-
- nextSym = rhs[pos]
- key = (X.stateno, nextSym)
- if nextSym not in rules:
- if key not in edges:
- edges[key] = None
- X.T.append(nextSym)
- else:
- edges[key] = None
- if nextSym not in predicted:
- predicted[nextSym] = 1
- for prule in rules[nextSym]:
- ppos = self.skip(prule)
- new = (prule, ppos)
- NK.items.append(new)
- #
- # Problem: we know K needs generating, but we
- # don't yet know about NK. Can't commit anything
- # regarding NK to self.edges until we're sure. Should
- # we delay committing on both K and NK to avoid this
- # hacky code? This creates other problems..
- #
- if X is K:
- edges = {}
-
- if NK.items == []:
- return k
-
- #
- # Check for \epsilon-nonkernel's core. Unfortunately we
- # need to know the entire set of predicted nonterminals
- # to do this without accidentally duplicating states.
- #
- core = sorted(predicted.keys())
- tcore = tuple(core)
- if tcore in self.cores:
- self.edges[(k, None)] = self.cores[tcore]
- return k
-
- nk = self.cores[tcore] = self.edges[(k, None)] = NK.stateno
- self.edges.update(edges)
- self.states[nk] = NK
- return k
-
- def goto(self, state, sym):
- key = (state, sym)
- if key not in self.edges:
- #
- # No transitions from state on sym.
- #
- return None
-
- rv = self.edges[key]
- if rv is None:
- #
- # Target state isn't generated yet. Remedy this.
- #
- rv = self.makeState(state, sym)
- self.edges[key] = rv
- return rv
-
- def gotoT(self, state, t):
- return [self.goto(state, t)]
-
- def gotoST(self, state, st):
- rv = []
- for t in self.states[state].T:
- if st == t:
- rv.append(self.goto(state, t))
- return rv
-
- def add(self, set, item, i=None, predecessor=None, causal=None):
- if predecessor is None:
- if item not in set:
- set.append(item)
- else:
- key = (item, i)
- if item not in set:
- self.links[key] = []
- set.append(item)
- self.links[key].append((predecessor, causal))
-
- def makeSet(self, token, sets, i):
- cur, next = sets[i], sets[i+1]
-
- ttype = token is not None and self.typestring(token) or None
- if ttype is not None:
- fn, arg = self.gotoT, ttype
- else:
- fn, arg = self.gotoST, token
-
- for item in cur:
- ptr = (item, i)
- state, parent = item
- add = fn(state, arg)
- for k in add:
- if k is not None:
- self.add(next, (k, parent), i+1, ptr)
- nk = self.goto(k, None)
- if nk is not None:
- self.add(next, (nk, i+1))
-
- if parent == i:
- continue
-
- for rule in self.states[state].complete:
- lhs, rhs = rule
- for pitem in sets[parent]:
- pstate, pparent = pitem
- k = self.goto(pstate, lhs)
- if k is not None:
- why = (item, i, rule)
- pptr = (pitem, parent)
- self.add(cur, (k, pparent),
- i, pptr, why)
- nk = self.goto(k, None)
- if nk is not None:
- self.add(cur, (nk, i))
-
- def makeSet_fast(self, token, sets, i):
- #
- # Call *only* when the entire state machine has been built!
- # It relies on self.edges being filled in completely, and
- # then duplicates and inlines code to boost speed at the
- # cost of extreme ugliness.
- #
- cur, next = sets[i], sets[i+1]
- ttype = token is not None and self.typestring(token) or None
-
- for item in cur:
- ptr = (item, i)
- state, parent = item
- if ttype is not None:
- k = self.edges.get((state, ttype), None)
- if k is not None:
- #self.add(next, (k, parent), i+1, ptr)
- #INLINED --v
- new = (k, parent)
- key = (new, i+1)
- if new not in next:
- self.links[key] = []
- next.append(new)
- self.links[key].append((ptr, None))
- #INLINED --^
- #nk = self.goto(k, None)
- nk = self.edges.get((k, None), None)
- if nk is not None:
- #self.add(next, (nk, i+1))
- #INLINED --v
- new = (nk, i+1)
- if new not in next:
- next.append(new)
- #INLINED --^
- else:
- add = self.gotoST(state, token)
- for k in add:
- if k is not None:
- self.add(next, (k, parent), i+1, ptr)
- #nk = self.goto(k, None)
- nk = self.edges.get((k, None), None)
- if nk is not None:
- self.add(next, (nk, i+1))
-
- if parent == i:
- continue
-
- for rule in self.states[state].complete:
- lhs, rhs = rule
- for pitem in sets[parent]:
- pstate, pparent = pitem
- #k = self.goto(pstate, lhs)
- k = self.edges.get((pstate, lhs), None)
- if k is not None:
- why = (item, i, rule)
- pptr = (pitem, parent)
- #self.add(cur, (k, pparent),
- # i, pptr, why)
- #INLINED --v
- new = (k, pparent)
- key = (new, i)
- if new not in cur:
- self.links[key] = []
- cur.append(new)
- self.links[key].append((pptr, why))
- #INLINED --^
- #nk = self.goto(k, None)
- nk = self.edges.get((k, None), None)
- if nk is not None:
- #self.add(cur, (nk, i))
- #INLINED --v
- new = (nk, i)
- if new not in cur:
- cur.append(new)
- #INLINED --^
-
- def predecessor(self, key, causal):
- for p, c in self.links[key]:
- if c == causal:
- return p
- assert 0
-
- def causal(self, key):
- links = self.links[key]
- if len(links) == 1:
- return links[0][1]
- choices = []
- rule2cause = {}
- for p, c in links:
- rule = c[2]
- choices.append(rule)
- rule2cause[rule] = c
- return rule2cause[self.ambiguity(choices)]
-
- def deriveEpsilon(self, nt):
- if len(self.newrules[nt]) > 1:
- rule = self.ambiguity(self.newrules[nt])
- else:
- rule = self.newrules[nt][0]
- #output(rule)
-
- rhs = rule[1]
- attr = [None] * len(rhs)
-
- for i in range(len(rhs)-1, -1, -1):
- attr[i] = self.deriveEpsilon(rhs[i])
- return self.rule2func[self.new2old[rule]](attr)
-
- def buildTree(self, nt, item, tokens, k):
- state, parent = item
-
- choices = []
- for rule in self.states[state].complete:
- if rule[0] == nt:
- choices.append(rule)
- rule = choices[0]
- if len(choices) > 1:
- rule = self.ambiguity(choices)
- #output(rule)
-
- rhs = rule[1]
- attr = [None] * len(rhs)
-
- for i in range(len(rhs)-1, -1, -1):
- sym = rhs[i]
- if sym not in self.newrules:
- if sym != self._BOF:
- attr[i] = tokens[k-1]
- key = (item, k)
- item, k = self.predecessor(key, None)
- #elif self.isnullable(sym):
- elif self._NULLABLE == sym[0:len(self._NULLABLE)]:
- attr[i] = self.deriveEpsilon(sym)
- else:
- key = (item, k)
- why = self.causal(key)
- attr[i] = self.buildTree(sym, why[0],
- tokens, why[1])
- item, k = self.predecessor(key, why)
- return self.rule2func[self.new2old[rule]](attr)
-
- def ambiguity(self, rules):
- #
- # XXX - problem here and in collectRules() if the same rule
- # appears in >1 method. Also undefined results if rules
- # causing the ambiguity appear in the same method.
- #
- sortlist = []
- name2index = {}
- for i in range(len(rules)):
- lhs, rhs = rule = rules[i]
- name = self.rule2name[self.new2old[rule]]
- sortlist.append((len(rhs), name))
- name2index[name] = i
- sortlist.sort()
- list = [b for a, b in sortlist]
- return rules[name2index[self.resolve(list)]]
-
- def resolve(self, list):
- #
- # Resolve ambiguity in favor of the shortest RHS.
- # Since we walk the tree from the top down, this
- # should effectively resolve in favor of a "shift".
- #
- return list[0]
-
-#
-# GenericASTBuilder automagically constructs a concrete/abstract syntax tree
-# for a given input. The extra argument is a class (not an instance!)
-# which supports the "__setslice__" and "__len__" methods.
-#
-# XXX - silently overrides any user code in methods.
-#
-
-class GenericASTBuilder(GenericParser):
- def __init__(self, AST, start):
- GenericParser.__init__(self, start)
- self.AST = AST
-
- def preprocess(self, rule, func):
- rebind = lambda lhs, self=self: \
- lambda args, lhs=lhs, self=self: \
- self.buildASTNode(args, lhs)
- lhs, rhs = rule
- return rule, rebind(lhs)
-
- def buildASTNode(self, args, lhs):
- children = []
- for arg in args:
- if isinstance(arg, self.AST):
- children.append(arg)
- else:
- children.append(self.terminal(arg))
- return self.nonterminal(lhs, children)
-
- def terminal(self, token): return token
-
- def nonterminal(self, type, args):
- rv = self.AST(type)
- rv[:len(args)] = args
- return rv
-
-#
-# GenericASTTraversal is a Visitor pattern according to Design Patterns. For
-# each node it attempts to invoke the method n_<node type>, falling
-# back onto the default() method if the n_* can't be found. The preorder
-# traversal also looks for an exit hook named n_<node type>_exit (no default
-# routine is called if it's not found). To prematurely halt traversal
-# of a subtree, call the prune() method -- this only makes sense for a
-# preorder traversal. Node type is determined via the typestring() method.
-#
-
-class GenericASTTraversalPruningException:
- pass
-
-class GenericASTTraversal:
- def __init__(self, ast):
- self.ast = ast
-
- def typestring(self, node):
- return node.type
-
- def prune(self):
- raise GenericASTTraversalPruningException
-
- def preorder(self, node=None):
- if node is None:
- node = self.ast
-
- try:
- name = 'n_' + self.typestring(node)
- if hasattr(self, name):
- func = getattr(self, name)
- func(node)
- else:
- self.default(node)
- except GenericASTTraversalPruningException:
- return
-
- for kid in node:
- self.preorder(kid)
-
- name = name + '_exit'
- if hasattr(self, name):
- func = getattr(self, name)
- func(node)
-
- def postorder(self, node=None):
- if node is None:
- node = self.ast
-
- for kid in node:
- self.postorder(kid)
-
- name = 'n_' + self.typestring(node)
- if hasattr(self, name):
- func = getattr(self, name)
- func(node)
- else:
- self.default(node)
-
-
- def default(self, node):
- pass
-
-#
-# GenericASTMatcher. AST nodes must have "__getitem__" and "__cmp__"
-# implemented.
-#
-# XXX - makes assumptions about how GenericParser walks the parse tree.
-#
-
-class GenericASTMatcher(GenericParser):
- def __init__(self, start, ast):
- GenericParser.__init__(self, start)
- self.ast = ast
-
- def preprocess(self, rule, func):
- rebind = lambda func, self=self: \
- lambda args, func=func, self=self: \
- self.foundMatch(args, func)
- lhs, rhs = rule
- rhslist = list(rhs)
- rhslist.reverse()
-
- return (lhs, tuple(rhslist)), rebind(func)
-
- def foundMatch(self, args, func):
- func(args[-1])
- return args[-1]
-
- def match_r(self, node):
- self.input.insert(0, node)
- children = 0
-
- for child in node:
- if children == 0:
- self.input.insert(0, '(')
- children = children + 1
- self.match_r(child)
-
- if children > 0:
- self.input.insert(0, ')')
-
- def match(self, ast=None):
- if ast is None:
- ast = self.ast
- self.input = []
-
- self.match_r(ast)
- self.parse(self.input)
-
- def resolve(self, list):
- #
- # Resolve ambiguity in favor of the longest RHS.
- #
- return list[-1]
-
-def _dump(tokens, sets, states):
- for i in range(len(sets)):
- output('set %d' % i)
- for item in sets[i]:
- output('\t', item)
- for (lhs, rhs), pos in states[item[0]].items:
- output('\t\t', lhs, '::=', end='')
- output(' '.join(rhs[:pos]), end='')
- output('.', end='')
- output(' '.join(rhs[pos:]))
- if i < len(tokens):
- output()
- output('token %s' % str(tokens[i]))
- output()
--
Repository URL: http://hg.python.org/cpython
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