summaryrefslogtreecommitdiff
path: root/ext/ply/yacc.py
diff options
context:
space:
mode:
authorNathan Binkert <binkertn@umich.edu>2007-05-24 21:54:51 -0700
committerNathan Binkert <binkertn@umich.edu>2007-05-24 21:54:51 -0700
commit44ebb8d3e27329e9f0b501897585359b4ab696f2 (patch)
tree536ed9dba1458f0d13d680ccfbb5f7ec3b79109c /ext/ply/yacc.py
parent9f1c104ccd835ce390d9e9fd24e59a6ea626ed17 (diff)
downloadgem5-44ebb8d3e27329e9f0b501897585359b4ab696f2.tar.xz
Update to ply 2.3
ext/ply/ply/lex.py: ext/ply/ply/yacc.py: ext/ply/CHANGES: ext/ply/README: ext/ply/TODO: ext/ply/doc/ply.html: ext/ply/example/ansic/clex.py: ext/ply/example/ansic/cparse.py: ext/ply/example/calc/calc.py: ext/ply/example/hedit/hedit.py: ext/ply/example/optcalc/calc.py: ext/ply/test/README: ext/ply/test/calclex.py: ext/ply/test/lex_doc1.exp: ext/ply/test/lex_doc1.py: ext/ply/test/lex_dup1.exp: ext/ply/test/lex_dup1.py: ext/ply/test/lex_dup2.exp: ext/ply/test/lex_dup2.py: ext/ply/test/lex_dup3.exp: ext/ply/test/lex_dup3.py: ext/ply/test/lex_empty.py: ext/ply/test/lex_error1.py: ext/ply/test/lex_error2.py: ext/ply/test/lex_error3.exp: ext/ply/test/lex_error3.py: ext/ply/test/lex_error4.exp: ext/ply/test/lex_error4.py: ext/ply/test/lex_hedit.exp: ext/ply/test/lex_hedit.py: ext/ply/test/lex_ignore.exp: ext/ply/test/lex_ignore.py: ext/ply/test/lex_re1.exp: ext/ply/test/lex_re1.py: ext/ply/test/lex_rule1.py: ext/ply/test/lex_token1.py: ext/ply/test/lex_token2.py: ext/ply/test/lex_token3.py: ext/ply/test/lex_token4.py: ext/ply/test/lex_token5.exp: ext/ply/test/lex_token5.py: ext/ply/test/yacc_badargs.exp: ext/ply/test/yacc_badargs.py: ext/ply/test/yacc_badprec.exp: ext/ply/test/yacc_badprec.py: ext/ply/test/yacc_badprec2.exp: ext/ply/test/yacc_badprec2.py: ext/ply/test/yacc_badrule.exp: ext/ply/test/yacc_badrule.py: ext/ply/test/yacc_badtok.exp: ext/ply/test/yacc_badtok.py: ext/ply/test/yacc_dup.exp: ext/ply/test/yacc_dup.py: ext/ply/test/yacc_error1.exp: ext/ply/test/yacc_error1.py: ext/ply/test/yacc_error2.exp: ext/ply/test/yacc_error2.py: ext/ply/test/yacc_error3.exp: ext/ply/test/yacc_error3.py: ext/ply/test/yacc_inf.exp: ext/ply/test/yacc_inf.py: ext/ply/test/yacc_missing1.exp: ext/ply/test/yacc_missing1.py: ext/ply/test/yacc_nodoc.exp: ext/ply/test/yacc_nodoc.py: ext/ply/test/yacc_noerror.exp: ext/ply/test/yacc_noerror.py: ext/ply/test/yacc_nop.exp: ext/ply/test/yacc_nop.py: ext/ply/test/yacc_notfunc.exp: ext/ply/test/yacc_notfunc.py: ext/ply/test/yacc_notok.exp: ext/ply/test/yacc_notok.py: ext/ply/test/yacc_rr.exp: ext/ply/test/yacc_rr.py: ext/ply/test/yacc_simple.exp: ext/ply/test/yacc_simple.py: ext/ply/test/yacc_sr.exp: ext/ply/test/yacc_sr.py: ext/ply/test/yacc_term1.exp: ext/ply/test/yacc_term1.py: ext/ply/test/yacc_unused.exp: ext/ply/test/yacc_unused.py: ext/ply/test/yacc_uprec.exp: ext/ply/test/yacc_uprec.py: Import patch ply.diff src/arch/isa_parser.py: everything is now within the ply package --HG-- rename : ext/ply/lex.py => ext/ply/ply/lex.py rename : ext/ply/yacc.py => ext/ply/ply/yacc.py extra : convert_revision : fca8deabd5c095bdeabd52a1f236ae1404ef106e
Diffstat (limited to 'ext/ply/yacc.py')
-rw-r--r--ext/ply/yacc.py1846
1 files changed, 0 insertions, 1846 deletions
diff --git a/ext/ply/yacc.py b/ext/ply/yacc.py
deleted file mode 100644
index 1041745ed..000000000
--- a/ext/ply/yacc.py
+++ /dev/null
@@ -1,1846 +0,0 @@
-#-----------------------------------------------------------------------------
-# ply: yacc.py
-#
-# Author: David M. Beazley (beazley@cs.uchicago.edu)
-# Department of Computer Science
-# University of Chicago
-# Chicago, IL 60637
-#
-# Copyright (C) 2001, David M. Beazley
-#
-# $Header: /home/stever/bk/newmem2/ext/ply/yacc.py 1.3 03/06/06 14:59:28-00:00 stever@ $
-#
-# This library is free software; you can redistribute it and/or
-# modify it under the terms of the GNU Lesser General Public
-# License as published by the Free Software Foundation; either
-# version 2.1 of the License, or (at your option) any later version.
-#
-# This library is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-# Lesser General Public License for more details.
-#
-# You should have received a copy of the GNU Lesser General Public
-# License along with this library; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-#
-# See the file COPYING for a complete copy of the LGPL.
-#
-#
-# This implements an LR parser that is constructed from grammar rules defined
-# as Python functions. Roughly speaking, this module is a cross between
-# John Aycock's Spark system and the GNU bison utility.
-#
-# Disclaimer: This is a work in progress. SLR parsing seems to work fairly
-# well and there is extensive error checking. LALR(1) is in progress. The
-# rest of this file is a bit of a mess. Please pardon the dust.
-#
-# The current implementation is only somewhat object-oriented. The
-# LR parser itself is defined in terms of an object (which allows multiple
-# parsers to co-exist). However, most of the variables used during table
-# construction are defined in terms of global variables. Users shouldn't
-# notice unless they are trying to define multiple parsers at the same
-# time using threads (in which case they should have their head examined).
-#-----------------------------------------------------------------------------
-
-__version__ = "1.3"
-
-#-----------------------------------------------------------------------------
-# === User configurable parameters ===
-#
-# Change these to modify the default behavior of yacc (if you wish)
-#-----------------------------------------------------------------------------
-
-yaccdebug = 1 # Debugging mode. If set, yacc generates a
- # a 'parser.out' file in the current directory
-
-debug_file = 'parser.out' # Default name of the debugging file
-tab_module = 'parsetab' # Default name of the table module
-default_lr = 'SLR' # Default LR table generation method
-
-error_count = 3 # Number of symbols that must be shifted to leave recovery mode
-
-import re, types, sys, cStringIO, md5, os.path
-
-# Exception raised for yacc-related errors
-class YaccError(Exception): pass
-
-#-----------------------------------------------------------------------------
-# === LR Parsing Engine ===
-#
-# The following classes are used for the LR parser itself. These are not
-# used during table construction and are independent of the actual LR
-# table generation algorithm
-#-----------------------------------------------------------------------------
-
-# This class is used to hold non-terminal grammar symbols during parsing.
-# It normally has the following attributes set:
-# .type = Grammar symbol type
-# .value = Symbol value
-# .lineno = Starting line number
-# .endlineno = Ending line number (optional, set automatically)
-
-class YaccSymbol:
- def __str__(self): return self.type
- def __repr__(self): return str(self)
-
-# This class is a wrapper around the objects actually passed to each
-# grammar rule. Index lookup and assignment actually assign the
-# .value attribute of the underlying YaccSymbol object.
-# The lineno() method returns the line number of a given
-# item (or 0 if not defined). The linespan() method returns
-# a tuple of (startline,endline) representing the range of lines
-# for a symbol.
-
-class YaccSlice:
- def __init__(self,s):
- self.slice = s
- self.pbstack = []
-
- def __getitem__(self,n):
- return self.slice[n].value
-
- def __setitem__(self,n,v):
- self.slice[n].value = v
-
- def __len__(self):
- return len(self.slice)
-
- def lineno(self,n):
- return getattr(self.slice[n],"lineno",0)
-
- def linespan(self,n):
- startline = getattr(self.slice[n],"lineno",0)
- endline = getattr(self.slice[n],"endlineno",startline)
- return startline,endline
-
- def pushback(self,n):
- if n <= 0:
- raise ValueError, "Expected a positive value"
- if n > (len(self.slice)-1):
- raise ValueError, "Can't push %d tokens. Only %d are available." % (n,len(self.slice)-1)
- for i in range(0,n):
- self.pbstack.append(self.slice[-i-1])
-
-# The LR Parsing engine. This is defined as a class so that multiple parsers
-# can exist in the same process. A user never instantiates this directly.
-# Instead, the global yacc() function should be used to create a suitable Parser
-# object.
-
-class Parser:
- def __init__(self,magic=None):
-
- # This is a hack to keep users from trying to instantiate a Parser
- # object directly.
-
- if magic != "xyzzy":
- raise YaccError, "Can't instantiate Parser. Use yacc() instead."
-
- # Reset internal state
- self.productions = None # List of productions
- self.errorfunc = None # Error handling function
- self.action = { } # LR Action table
- self.goto = { } # LR goto table
- self.require = { } # Attribute require table
- self.method = "Unknown LR" # Table construction method used
-
- def errok(self):
- self.errorcount = 0
-
- def restart(self):
- del self.statestack[:]
- del self.symstack[:]
- sym = YaccSymbol()
- sym.type = '$'
- self.symstack.append(sym)
- self.statestack.append(0)
-
- def parse(self,input=None,lexer=None,debug=0):
- lookahead = None # Current lookahead symbol
- lookaheadstack = [ ] # Stack of lookahead symbols
- actions = self.action # Local reference to action table
- goto = self.goto # Local reference to goto table
- prod = self.productions # Local reference to production list
- pslice = YaccSlice(None) # Slice object passed to grammar rules
- pslice.parser = self # Parser object
- self.errorcount = 0 # Used during error recovery
-
- # If no lexer was given, we will try to use the lex module
- if not lexer:
- import lex as lexer
-
- pslice.lexer = lexer
-
- # If input was supplied, pass to lexer
- if input:
- lexer.input(input)
-
- # Tokenize function
- get_token = lexer.token
-
- statestack = [ ] # Stack of parsing states
- self.statestack = statestack
- symstack = [ ] # Stack of grammar symbols
- self.symstack = symstack
-
- errtoken = None # Err token
-
- # The start state is assumed to be (0,$)
- statestack.append(0)
- sym = YaccSymbol()
- sym.type = '$'
- symstack.append(sym)
-
- while 1:
- # Get the next symbol on the input. If a lookahead symbol
- # is already set, we just use that. Otherwise, we'll pull
- # the next token off of the lookaheadstack or from the lexer
- if not lookahead:
- if not lookaheadstack:
- lookahead = get_token() # Get the next token
- else:
- lookahead = lookaheadstack.pop()
- if not lookahead:
- lookahead = YaccSymbol()
- lookahead.type = '$'
- if debug:
- print "%-20s : %s" % (lookahead, [xx.type for xx in symstack])
-
- # Check the action table
- s = statestack[-1]
- ltype = lookahead.type
- t = actions.get((s,ltype),None)
-
- if t is not None:
- if t > 0:
- # shift a symbol on the stack
- if ltype == '$':
- # Error, end of input
- print "yacc: Parse error. EOF"
- return
- statestack.append(t)
- symstack.append(lookahead)
- lookahead = None
-
- # Decrease error count on successful shift
- if self.errorcount > 0:
- self.errorcount -= 1
-
- continue
-
- if t < 0:
- # reduce a symbol on the stack, emit a production
- p = prod[-t]
- pname = p.name
- plen = p.len
-
- # Get production function
- sym = YaccSymbol()
- sym.type = pname # Production name
- sym.value = None
-
- if plen:
- targ = symstack[-plen-1:]
- targ[0] = sym
- try:
- sym.lineno = targ[1].lineno
- sym.endlineno = getattr(targ[-1],"endlineno",targ[-1].lineno)
- except AttributeError:
- sym.lineno = 0
- del symstack[-plen:]
- del statestack[-plen:]
- else:
- sym.lineno = 0
- targ = [ sym ]
- pslice.slice = targ
- pslice.pbstack = []
- # Call the grammar rule with our special slice object
- p.func(pslice)
-
- # Validate attributes of the resulting value attribute
-# if require:
-# try:
-# t0 = targ[0]
-# r = Requires.get(t0.type,None)
-# t0d = t0.__dict__
-# if r:
-# for field in r:
-# tn = t0
-# for fname in field:
-# try:
-# tf = tn.__dict__
-# tn = tf.get(fname)
-# except StandardError:
-# tn = None
-# if not tn:
-# print "%s:%d: Rule %s doesn't set required attribute '%s'" % \
-# (p.file,p.line,p.name,".".join(field))
-# except TypeError,LookupError:
-# print "Bad requires directive " % r
-# pass
-
-
- # If there was a pushback, put that on the stack
- if pslice.pbstack:
- lookaheadstack.append(lookahead)
- for _t in pslice.pbstack:
- lookaheadstack.append(_t)
- lookahead = None
-
- symstack.append(sym)
- statestack.append(goto[statestack[-1],pname])
- continue
-
- if t == 0:
- n = symstack[-1]
- return getattr(n,"value",None)
-
- if t == None:
- # We have some kind of parsing error here. To handle this,
- # we are going to push the current token onto the tokenstack
- # and replace it with an 'error' token. If there are any synchronization
- # rules, they may catch it.
- #
- # In addition to pushing the error token, we call call the user defined p_error()
- # function if this is the first syntax error. This function is only called
- # if errorcount == 0.
-
- if not self.errorcount:
- self.errorcount = error_count
- errtoken = lookahead
- if errtoken.type == '$':
- errtoken = None # End of file!
- if self.errorfunc:
- global errok,token,restart
- errok = self.errok # Set some special functions available in error recovery
- token = get_token
- restart = self.restart
- tok = self.errorfunc(errtoken)
- del errok, token, restart # Delete special functions
-
- if not self.errorcount:
- # User must have done some kind of panic mode recovery on their own. The returned token
- # is the next lookahead
- lookahead = tok
- errtoken = None
- continue
- else:
- if errtoken:
- if hasattr(errtoken,"lineno"): lineno = lookahead.lineno
- else: lineno = 0
- if lineno:
- print "yacc: Syntax error at line %d, token=%s" % (lineno, errtoken.type)
- else:
- print "yacc: Syntax error, token=%s" % errtoken.type
- else:
- print "yacc: Parse error in input. EOF"
- return
-
- else:
- self.errorcount = error_count
-
- # case 1: the statestack only has 1 entry on it. If we're in this state, the
- # entire parse has been rolled back and we're completely hosed. The token is
- # discarded and we just keep going.
-
- if len(statestack) <= 1 and lookahead.type != '$':
- lookahead = None
- errtoken = None
- # Nuke the pushback stack
- del lookaheadstack[:]
- continue
-
- # case 2: the statestack has a couple of entries on it, but we're
- # at the end of the file. nuke the top entry and generate an error token
-
- # Start nuking entries on the stack
- if lookahead.type == '$':
- # Whoa. We're really hosed here. Bail out
- return
-
- if lookahead.type != 'error':
- sym = symstack[-1]
- if sym.type == 'error':
- # Hmmm. Error is on top of stack, we'll just nuke input
- # symbol and continue
- lookahead = None
- continue
- t = YaccSymbol()
- t.type = 'error'
- if hasattr(lookahead,"lineno"):
- t.lineno = lookahead.lineno
- t.value = lookahead
- lookaheadstack.append(lookahead)
- lookahead = t
- else:
- symstack.pop()
- statestack.pop()
-
- continue
-
- # Call an error function here
- raise RuntimeError, "yacc: internal parser error!!!\n"
-
-# -----------------------------------------------------------------------------
-# === Parser Construction ===
-#
-# The following functions and variables are used to implement the yacc() function
-# itself. This is pretty hairy stuff involving lots of error checking,
-# construction of LR items, kernels, and so forth. Although a lot of
-# this work is done using global variables, the resulting Parser object
-# is completely self contained--meaning that it is safe to repeatedly
-# call yacc() with different grammars in the same application.
-# -----------------------------------------------------------------------------
-
-# -----------------------------------------------------------------------------
-# validate_file()
-#
-# This function checks to see if there are duplicated p_rulename() functions
-# in the parser module file. Without this function, it is really easy for
-# users to make mistakes by cutting and pasting code fragments (and it's a real
-# bugger to try and figure out why the resulting parser doesn't work). Therefore,
-# we just do a little regular expression pattern matching of def statements
-# to try and detect duplicates.
-# -----------------------------------------------------------------------------
-
-def validate_file(filename):
- base,ext = os.path.splitext(filename)
- if ext != '.py': return 1 # No idea. Assume it's okay.
-
- try:
- f = open(filename)
- lines = f.readlines()
- f.close()
- except IOError:
- return 1 # Oh well
-
- # Match def p_funcname(
- fre = re.compile(r'\s*def\s+(p_[a-zA-Z_0-9]*)\(')
- counthash = { }
- linen = 1
- noerror = 1
- for l in lines:
- m = fre.match(l)
- if m:
- name = m.group(1)
- prev = counthash.get(name)
- if not prev:
- counthash[name] = linen
- else:
- print "%s:%d: Function %s redefined. Previously defined on line %d" % (filename,linen,name,prev)
- noerror = 0
- linen += 1
- return noerror
-
-# This function looks for functions that might be grammar rules, but which don't have the proper p_suffix.
-def validate_dict(d):
- for n,v in d.items():
- if n[0:2] == 'p_' and isinstance(v,types.FunctionType): continue
- if n[0:2] == 't_': continue
-
- if n[0:2] == 'p_':
- print "yacc: Warning. '%s' not defined as a function" % n
- if isinstance(v,types.FunctionType) and v.func_code.co_argcount == 1:
- try:
- doc = v.__doc__.split(" ")
- if doc[1] == ':':
- print "%s:%d: Warning. Possible grammar rule '%s' defined without p_ prefix." % (v.func_code.co_filename, v.func_code.co_firstlineno,n)
- except StandardError:
- pass
-
-# -----------------------------------------------------------------------------
-# === GRAMMAR FUNCTIONS ===
-#
-# The following global variables and functions are used to store, manipulate,
-# and verify the grammar rules specified by the user.
-# -----------------------------------------------------------------------------
-
-# Initialize all of the global variables used during grammar construction
-def initialize_vars():
- global Productions, Prodnames, Prodmap, Terminals
- global Nonterminals, First, Follow, Precedence, LRitems
- global Errorfunc, Signature, Requires
-
- Productions = [None] # A list of all of the productions. The first
- # entry is always reserved for the purpose of
- # building an augmented grammar
-
- Prodnames = { } # A dictionary mapping the names of nonterminals to a list of all
- # productions of that nonterminal.
-
- Prodmap = { } # A dictionary that is only used to detect duplicate
- # productions.
-
- Terminals = { } # A dictionary mapping the names of terminal symbols to a
- # list of the rules where they are used.
-
- Nonterminals = { } # A dictionary mapping names of nonterminals to a list
- # of rule numbers where they are used.
-
- First = { } # A dictionary of precomputed FIRST(x) symbols
-
- Follow = { } # A dictionary of precomputed FOLLOW(x) symbols
-
- Precedence = { } # Precedence rules for each terminal. Contains tuples of the
- # form ('right',level) or ('nonassoc', level) or ('left',level)
-
- LRitems = [ ] # A list of all LR items for the grammar. These are the
- # productions with the "dot" like E -> E . PLUS E
-
- Errorfunc = None # User defined error handler
-
- Signature = md5.new() # Digital signature of the grammar rules, precedence
- # and other information. Used to determined when a
- # parsing table needs to be regenerated.
-
- Requires = { } # Requires list
-
- # File objects used when creating the parser.out debugging file
- global _vf, _vfc
- _vf = cStringIO.StringIO()
- _vfc = cStringIO.StringIO()
-
-# -----------------------------------------------------------------------------
-# class Production:
-#
-# This class stores the raw information about a single production or grammar rule.
-# It has a few required attributes:
-#
-# name - Name of the production (nonterminal)
-# prod - A list of symbols making up its production
-# number - Production number.
-#
-# In addition, a few additional attributes are used to help with debugging or
-# optimization of table generation.
-#
-# file - File where production action is defined.
-# lineno - Line number where action is defined
-# func - Action function
-# prec - Precedence level
-# lr_next - Next LR item. Example, if we are ' E -> E . PLUS E'
-# then lr_next refers to 'E -> E PLUS . E'
-# lr_index - LR item index (location of the ".") in the prod list.
-# len - Length of the production (number of symbols on right hand side)
-# -----------------------------------------------------------------------------
-
-class Production:
- def __init__(self,**kw):
- for k,v in kw.items():
- setattr(self,k,v)
- self.lr_index = -1
- self.lr0_added = 0 # Flag indicating whether or not added to LR0 closure
- self.usyms = [ ]
-
- def __str__(self):
- if self.prod:
- s = "%s -> %s" % (self.name," ".join(self.prod))
- else:
- s = "%s -> <empty>" % self.name
- return s
-
- def __repr__(self):
- return str(self)
-
- # Compute lr_items from the production
- def lr_item(self,n):
- if n > len(self.prod): return None
- p = Production()
- p.name = self.name
- p.prod = list(self.prod)
- p.number = self.number
- p.lr_index = n
- p.prod.insert(n,".")
- p.prod = tuple(p.prod)
- p.len = len(p.prod)
- p.usyms = self.usyms
-
- # Precompute list of productions immediately following
- try:
- p.lrafter = Prodnames[p.prod[n+1]]
- except (IndexError,KeyError),e:
- p.lrafter = []
- try:
- p.lrbefore = p.prod[n-1]
- except IndexError:
- p.lrbefore = None
-
- return p
-
-class MiniProduction:
- pass
-
-# Utility function
-def is_identifier(s):
- for c in s:
- if not (c.isalnum() or c == '_'): return 0
- return 1
-
-# -----------------------------------------------------------------------------
-# add_production()
-#
-# Given an action function, this function assembles a production rule.
-# The production rule is assumed to be found in the function's docstring.
-# This rule has the general syntax:
-#
-# name1 ::= production1
-# | production2
-# | production3
-# ...
-# | productionn
-# name2 ::= production1
-# | production2
-# ...
-# -----------------------------------------------------------------------------
-
-def add_production(f,file,line,prodname,syms):
-
- if Terminals.has_key(prodname):
- print "%s:%d: Illegal rule name '%s'. Already defined as a token." % (file,line,prodname)
- return -1
- if prodname == 'error':
- print "%s:%d: Illegal rule name '%s'. error is a reserved word." % (file,line,prodname)
- return -1
-
- if not is_identifier(prodname):
- print "%s:%d: Illegal rule name '%s'" % (file,line,prodname)
- return -1
-
- for s in syms:
- if not is_identifier(s) and s != '%prec':
- print "%s:%d: Illegal name '%s' in rule '%s'" % (file,line,s, prodname)
- return -1
-
- # See if the rule is already in the rulemap
- map = "%s -> %s" % (prodname,syms)
- if Prodmap.has_key(map):
- m = Prodmap[map]
- print "%s:%d: Duplicate rule %s." % (file,line, m)
- print "%s:%d: Previous definition at %s:%d" % (file,line, m.file, m.line)
- return -1
-
- p = Production()
- p.name = prodname
- p.prod = syms
- p.file = file
- p.line = line
- p.func = f
- p.number = len(Productions)
-
-
- Productions.append(p)
- Prodmap[map] = p
- if not Nonterminals.has_key(prodname):
- Nonterminals[prodname] = [ ]
-
- # Add all terminals to Terminals
- i = 0
- while i < len(p.prod):
- t = p.prod[i]
- if t == '%prec':
- try:
- precname = p.prod[i+1]
- except IndexError:
- print "%s:%d: Syntax error. Nothing follows %%prec." % (p.file,p.line)
- return -1
-
- prec = Precedence.get(precname,None)
- if not prec:
- print "%s:%d: Nothing known about the precedence of '%s'" % (p.file,p.line,precname)
- return -1
- else:
- p.prec = prec
- del p.prod[i]
- del p.prod[i]
- continue
-
- if Terminals.has_key(t):
- Terminals[t].append(p.number)
- # Is a terminal. We'll assign a precedence to p based on this
- if not hasattr(p,"prec"):
- p.prec = Precedence.get(t,('right',0))
- else:
- if not Nonterminals.has_key(t):
- Nonterminals[t] = [ ]
- Nonterminals[t].append(p.number)
- i += 1
-
- if not hasattr(p,"prec"):
- p.prec = ('right',0)
-
- # Set final length of productions
- p.len = len(p.prod)
- p.prod = tuple(p.prod)
-
- # Calculate unique syms in the production
- p.usyms = [ ]
- for s in p.prod:
- if s not in p.usyms:
- p.usyms.append(s)
-
- # Add to the global productions list
- try:
- Prodnames[p.name].append(p)
- except KeyError:
- Prodnames[p.name] = [ p ]
- return 0
-
-# Given a raw rule function, this function rips out its doc string
-# and adds rules to the grammar
-
-def add_function(f):
- line = f.func_code.co_firstlineno
- file = f.func_code.co_filename
- error = 0
-
- if f.func_code.co_argcount > 1:
- print "%s:%d: Rule '%s' has too many arguments." % (file,line,f.__name__)
- return -1
-
- if f.func_code.co_argcount < 1:
- print "%s:%d: Rule '%s' requires an argument." % (file,line,f.__name__)
- return -1
-
- if f.__doc__:
- # Split the doc string into lines
- pstrings = f.__doc__.splitlines()
- lastp = None
- dline = line
- for ps in pstrings:
- dline += 1
- p = ps.split()
- if not p: continue
- try:
- if p[0] == '|':
- # This is a continuation of a previous rule
- if not lastp:
- print "%s:%d: Misplaced '|'." % (file,dline)
- return -1
- prodname = lastp
- if len(p) > 1:
- syms = p[1:]
- else:
- syms = [ ]
- else:
- prodname = p[0]
- lastp = prodname
- assign = p[1]
- if len(p) > 2:
- syms = p[2:]
- else:
- syms = [ ]
- if assign != ':' and assign != '::=':
- print "%s:%d: Syntax error. Expected ':'" % (file,dline)
- return -1
- e = add_production(f,file,dline,prodname,syms)
- error += e
- except StandardError:
- print "%s:%d: Syntax error in rule '%s'" % (file,dline,ps)
- error -= 1
- else:
- print "%s:%d: No documentation string specified in function '%s'" % (file,line,f.__name__)
- return error
-
-
-# Cycle checking code (Michael Dyck)
-
-def compute_reachable():
- '''
- Find each symbol that can be reached from the start symbol.
- Print a warning for any nonterminals that can't be reached.
- (Unused terminals have already had their warning.)
- '''
- Reachable = { }
- for s in Terminals.keys() + Nonterminals.keys():
- Reachable[s] = 0
-
- mark_reachable_from( Productions[0].prod[0], Reachable )
-
- for s in Nonterminals.keys():
- if not Reachable[s]:
- print "yacc: Symbol '%s' is unreachable." % s
-
-def mark_reachable_from(s, Reachable):
- '''
- Mark all symbols that are reachable from symbol s.
- '''
- if Reachable[s]:
- # We've already reached symbol s.
- return
- Reachable[s] = 1
- for p in Prodnames.get(s,[]):
- for r in p.prod:
- mark_reachable_from(r, Reachable)
-
-# -----------------------------------------------------------------------------
-# compute_terminates()
-#
-# This function looks at the various parsing rules and tries to detect
-# infinite recursion cycles (grammar rules where there is no possible way
-# to derive a string of only terminals).
-# -----------------------------------------------------------------------------
-def compute_terminates():
- '''
- Raise an error for any symbols that don't terminate.
- '''
- Terminates = {}
-
- # Terminals:
- for t in Terminals.keys():
- Terminates[t] = 1
-
- Terminates['$'] = 1
-
- # Nonterminals:
-
- # Initialize to false:
- for n in Nonterminals.keys():
- Terminates[n] = 0
-
- # Then propagate termination until no change:
- while 1:
- some_change = 0
- for (n,pl) in Prodnames.items():
- # Nonterminal n terminates iff any of its productions terminates.
- for p in pl:
- # Production p terminates iff all of its rhs symbols terminate.
- for s in p.prod:
- if not Terminates[s]:
- # The symbol s does not terminate,
- # so production p does not terminate.
- p_terminates = 0
- break
- else:
- # didn't break from the loop,
- # so every symbol s terminates
- # so production p terminates.
- p_terminates = 1
-
- if p_terminates:
- # symbol n terminates!
- if not Terminates[n]:
- Terminates[n] = 1
- some_change = 1
- # Don't need to consider any more productions for this n.
- break
-
- if not some_change:
- break
-
- some_error = 0
- for (s,terminates) in Terminates.items():
- if not terminates:
- if not Prodnames.has_key(s) and not Terminals.has_key(s) and s != 'error':
- # s is used-but-not-defined, and we've already warned of that,
- # so it would be overkill to say that it's also non-terminating.
- pass
- else:
- print "yacc: Infinite recursion detected for symbol '%s'." % s
- some_error = 1
-
- return some_error
-
-# -----------------------------------------------------------------------------
-# verify_productions()
-#
-# This function examines all of the supplied rules to see if they seem valid.
-# -----------------------------------------------------------------------------
-def verify_productions(cycle_check=1):
- error = 0
- for p in Productions:
- if not p: continue
-
- for s in p.prod:
- if not Prodnames.has_key(s) and not Terminals.has_key(s) and s != 'error':
- print "%s:%d: Symbol '%s' used, but not defined as a token or a rule." % (p.file,p.line,s)
- error = 1
- continue
-
- unused_tok = 0
- # Now verify all of the tokens
- if yaccdebug:
- _vf.write("Unused terminals:\n\n")
- for s,v in Terminals.items():
- if s != 'error' and not v:
- print "yacc: Warning. Token '%s' defined, but not used." % s
- if yaccdebug: _vf.write(" %s\n"% s)
- unused_tok += 1
-
- # Print out all of the productions
- if yaccdebug:
- _vf.write("\nGrammar\n\n")
- for i in range(1,len(Productions)):
- _vf.write("Rule %-5d %s\n" % (i, Productions[i]))
-
- unused_prod = 0
- # Verify the use of all productions
- for s,v in Nonterminals.items():
- if not v:
- p = Prodnames[s][0]
- print "%s:%d: Warning. Rule '%s' defined, but not used." % (p.file,p.line, s)
- unused_prod += 1
-
-
- if unused_tok == 1:
- print "yacc: Warning. There is 1 unused token."
- if unused_tok > 1:
- print "yacc: Warning. There are %d unused tokens." % unused_tok
-
- if unused_prod == 1:
- print "yacc: Warning. There is 1 unused rule."
- if unused_prod > 1:
- print "yacc: Warning. There are %d unused rules." % unused_prod
-
- if yaccdebug:
- _vf.write("\nTerminals, with rules where they appear\n\n")
- ks = Terminals.keys()
- ks.sort()
- for k in ks:
- _vf.write("%-20s : %s\n" % (k, " ".join([str(s) for s in Terminals[k]])))
- _vf.write("\nNonterminals, with rules where they appear\n\n")
- ks = Nonterminals.keys()
- ks.sort()
- for k in ks:
- _vf.write("%-20s : %s\n" % (k, " ".join([str(s) for s in Nonterminals[k]])))
-
- if (cycle_check):
- compute_reachable()
- error += compute_terminates()
-# error += check_cycles()
- return error
-
-# -----------------------------------------------------------------------------
-# build_lritems()
-#
-# This function walks the list of productions and builds a complete set of the
-# LR items. The LR items are stored in two ways: First, they are uniquely
-# numbered and placed in the list _lritems. Second, a linked list of LR items
-# is built for each production. For example:
-#
-# E -> E PLUS E
-#
-# Creates the list
-#
-# [E -> . E PLUS E, E -> E . PLUS E, E -> E PLUS . E, E -> E PLUS E . ]
-# -----------------------------------------------------------------------------
-
-def build_lritems():
- for p in Productions:
- lastlri = p
- lri = p.lr_item(0)
- i = 0
- while 1:
- lri = p.lr_item(i)
- lastlri.lr_next = lri
- if not lri: break
- lri.lr_num = len(LRitems)
- LRitems.append(lri)
- lastlri = lri
- i += 1
-
- # In order for the rest of the parser generator to work, we need to
- # guarantee that no more lritems are generated. Therefore, we nuke
- # the p.lr_item method. (Only used in debugging)
- # Production.lr_item = None
-
-# -----------------------------------------------------------------------------
-# add_precedence()
-#
-# Given a list of precedence rules, add to the precedence table.
-# -----------------------------------------------------------------------------
-
-def add_precedence(plist):
- plevel = 0
- error = 0
- for p in plist:
- plevel += 1
- try:
- prec = p[0]
- terms = p[1:]
- if prec != 'left' and prec != 'right' and prec != 'nonassoc':
- print "yacc: Invalid precedence '%s'" % prec
- return -1
- for t in terms:
- if Precedence.has_key(t):
- print "yacc: Precedence already specified for terminal '%s'" % t
- error += 1
- continue
- Precedence[t] = (prec,plevel)
- except:
- print "yacc: Invalid precedence table."
- error += 1
-
- return error
-
-# -----------------------------------------------------------------------------
-# augment_grammar()
-#
-# Compute the augmented grammar. This is just a rule S' -> start where start
-# is the starting symbol.
-# -----------------------------------------------------------------------------
-
-def augment_grammar(start=None):
- if not start:
- start = Productions[1].name
- Productions[0] = Production(name="S'",prod=[start],number=0,len=1,prec=('right',0),func=None)
- Productions[0].usyms = [ start ]
- Nonterminals[start].append(0)
-
-
-# -------------------------------------------------------------------------
-# first()
-#
-# Compute the value of FIRST1(beta) where beta is a tuple of symbols.
-#
-# During execution of compute_first1, the result may be incomplete.
-# Afterward (e.g., when called from compute_follow()), it will be complete.
-# -------------------------------------------------------------------------
-def first(beta):
-
- # We are computing First(x1,x2,x3,...,xn)
- result = [ ]
- for x in beta:
- x_produces_empty = 0
-
- # Add all the non-<empty> symbols of First[x] to the result.
- for f in First[x]:
- if f == '<empty>':
- x_produces_empty = 1
- else:
- if f not in result: result.append(f)
-
- if x_produces_empty:
- # We have to consider the next x in beta,
- # i.e. stay in the loop.
- pass
- else:
- # We don't have to consider any further symbols in beta.
- break
- else:
- # There was no 'break' from the loop,
- # so x_produces_empty was true for all x in beta,
- # so beta produces empty as well.
- result.append('<empty>')
-
- return result
-
-
-# FOLLOW(x)
-# Given a non-terminal. This function computes the set of all symbols
-# that might follow it. Dragon book, p. 189.
-
-def compute_follow(start=None):
- # Add '$' to the follow list of the start symbol
- for k in Nonterminals.keys():
- Follow[k] = [ ]
-
- if not start:
- start = Productions[1].name
-
- Follow[start] = [ '$' ]
-
- while 1:
- didadd = 0
- for p in Productions[1:]:
- # Here is the production set
- for i in range(len(p.prod)):
- B = p.prod[i]
- if Nonterminals.has_key(B):
- # Okay. We got a non-terminal in a production
- fst = first(p.prod[i+1:])
- hasempty = 0
- for f in fst:
- if f != '<empty>' and f not in Follow[B]:
- Follow[B].append(f)
- didadd = 1
- if f == '<empty>':
- hasempty = 1
- if hasempty or i == (len(p.prod)-1):
- # Add elements of follow(a) to follow(b)
- for f in Follow[p.name]:
- if f not in Follow[B]:
- Follow[B].append(f)
- didadd = 1
- if not didadd: break
-
- if 0 and yaccdebug:
- _vf.write('\nFollow:\n')
- for k in Nonterminals.keys():
- _vf.write("%-20s : %s\n" % (k, " ".join([str(s) for s in Follow[k]])))
-
-# -------------------------------------------------------------------------
-# compute_first1()
-#
-# Compute the value of FIRST1(X) for all symbols
-# -------------------------------------------------------------------------
-def compute_first1():
-
- # Terminals:
- for t in Terminals.keys():
- First[t] = [t]
-
- First['$'] = ['$']
- First['#'] = ['#'] # what's this for?
-
- # Nonterminals:
-
- # Initialize to the empty set:
- for n in Nonterminals.keys():
- First[n] = []
-
- # Then propagate symbols until no change:
- while 1:
- some_change = 0
- for n in Nonterminals.keys():
- for p in Prodnames[n]:
- for f in first(p.prod):
- if f not in First[n]:
- First[n].append( f )
- some_change = 1
- if not some_change:
- break
-
- if 0 and yaccdebug:
- _vf.write('\nFirst:\n')
- for k in Nonterminals.keys():
- _vf.write("%-20s : %s\n" %
- (k, " ".join([str(s) for s in First[k]])))
-
-# -----------------------------------------------------------------------------
-# === SLR Generation ===
-#
-# The following functions are used to construct SLR (Simple LR) parsing tables
-# as described on p.221-229 of the dragon book.
-# -----------------------------------------------------------------------------
-
-# Global variables for the LR parsing engine
-def lr_init_vars():
- global _lr_action, _lr_goto, _lr_method
- global _lr_goto_cache
-
- _lr_action = { } # Action table
- _lr_goto = { } # Goto table
- _lr_method = "Unknown" # LR method used
- _lr_goto_cache = { }
-
-# Compute the LR(0) closure operation on I, where I is a set of LR(0) items.
-# prodlist is a list of productions.
-
-_add_count = 0 # Counter used to detect cycles
-
-def lr0_closure(I):
- global _add_count
-
- _add_count += 1
- prodlist = Productions
-
- # Add everything in I to J
- J = I[:]
- didadd = 1
- while didadd:
- didadd = 0
- for j in J:
- for x in j.lrafter:
- if x.lr0_added == _add_count: continue
- # Add B --> .G to J
- J.append(x.lr_next)
- x.lr0_added = _add_count
- didadd = 1
-
- return J
-
-# Compute the LR(0) goto function goto(I,X) where I is a set
-# of LR(0) items and X is a grammar symbol. This function is written
-# in a way that guarantees uniqueness of the generated goto sets
-# (i.e. the same goto set will never be returned as two different Python
-# objects). With uniqueness, we can later do fast set comparisons using
-# id(obj) instead of element-wise comparison.
-
-def lr0_goto(I,x):
- # First we look for a previously cached entry
- g = _lr_goto_cache.get((id(I),x),None)
- if g: return g
-
- # Now we generate the goto set in a way that guarantees uniqueness
- # of the result
-
- s = _lr_goto_cache.get(x,None)
- if not s:
- s = { }
- _lr_goto_cache[x] = s
-
- gs = [ ]
- for p in I:
- n = p.lr_next
- if n and n.lrbefore == x:
- s1 = s.get(id(n),None)
- if not s1:
- s1 = { }
- s[id(n)] = s1
- gs.append(n)
- s = s1
- g = s.get('$',None)
- if not g:
- if gs:
- g = lr0_closure(gs)
- s['$'] = g
- else:
- s['$'] = gs
- _lr_goto_cache[(id(I),x)] = g
- return g
-
-# Compute the kernel of a set of LR(0) items
-def lr0_kernel(I):
- KI = [ ]
- for p in I:
- if p.name == "S'" or p.lr_index > 0 or p.len == 0:
- KI.append(p)
-
- return KI
-
-_lr0_cidhash = { }
-
-# Compute the LR(0) sets of item function
-def lr0_items():
-
- C = [ lr0_closure([Productions[0].lr_next]) ]
- i = 0
- for I in C:
- _lr0_cidhash[id(I)] = i
- i += 1
-
- # Loop over the items in C and each grammar symbols
- i = 0
- while i < len(C):
- I = C[i]
- i += 1
-
- # Collect all of the symbols that could possibly be in the goto(I,X) sets
- asyms = { }
- for ii in I:
- for s in ii.usyms:
- asyms[s] = None
-
- for x in asyms.keys():
- g = lr0_goto(I,x)
- if not g: continue
- if _lr0_cidhash.has_key(id(g)): continue
- _lr0_cidhash[id(g)] = len(C)
- C.append(g)
-
- return C
-
-# -----------------------------------------------------------------------------
-# slr_parse_table()
-#
-# This function constructs an SLR table.
-# -----------------------------------------------------------------------------
-def slr_parse_table():
- global _lr_method
- goto = _lr_goto # Goto array
- action = _lr_action # Action array
- actionp = { } # Action production array (temporary)
-
- _lr_method = "SLR"
-
- n_srconflict = 0
- n_rrconflict = 0
-
- if yaccdebug:
- _vf.write("\n\nParsing method: SLR\n\n")
-
- # Step 1: Construct C = { I0, I1, ... IN}, collection of LR(0) items
- # This determines the number of states
-
- C = lr0_items()
-
- # Build the parser table, state by state
- st = 0
- for I in C:
- # Loop over each production in I
- actlist = [ ] # List of actions
-
- if yaccdebug:
- _vf.write("\nstate %d\n\n" % st)
- for p in I:
- _vf.write(" (%d) %s\n" % (p.number, str(p)))
- _vf.write("\n")
-
- for p in I:
- try:
- if p.prod[-1] == ".":
- if p.name == "S'":
- # Start symbol. Accept!
- action[st,"$"] = 0
- actionp[st,"$"] = p
- else:
- # We are at the end of a production. Reduce!
- for a in Follow[p.name]:
- actlist.append((a,p,"reduce using rule %d (%s)" % (p.number,p)))
- r = action.get((st,a),None)
- if r is not None:
- # Whoa. Have a shift/reduce or reduce/reduce conflict
- if r > 0:
- # Need to decide on shift or reduce here
- # By default we favor shifting. Need to add
- # some precedence rules here.
- sprec,slevel = Productions[actionp[st,a].number].prec
- rprec,rlevel = Precedence.get(a,('right',0))
- if (slevel < rlevel) or ((slevel == rlevel) and (rprec == 'left')):
- # We really need to reduce here.
- action[st,a] = -p.number
- actionp[st,a] = p
- if not slevel and not rlevel:
- _vfc.write("shift/reduce conflict in state %d resolved as reduce.\n" % st)
- _vf.write(" ! shift/reduce conflict for %s resolved as reduce.\n" % a)
- n_srconflict += 1
- elif (slevel == rlevel) and (rprec == 'nonassoc'):
- action[st,a] = None
- else:
- # Hmmm. Guess we'll keep the shift
- if not slevel and not rlevel:
- _vfc.write("shift/reduce conflict in state %d resolved as shift.\n" % st)
- _vf.write(" ! shift/reduce conflict for %s resolved as shift.\n" % a)
- n_srconflict +=1
- elif r < 0:
- # Reduce/reduce conflict. In this case, we favor the rule
- # that was defined first in the grammar file
- oldp = Productions[-r]
- pp = Productions[p.number]
- if oldp.line > pp.line:
- action[st,a] = -p.number
- actionp[st,a] = p
- # print "Reduce/reduce conflict in state %d" % st
- n_rrconflict += 1
- _vfc.write("reduce/reduce conflict in state %d resolved using rule %d (%s).\n" % (st, actionp[st,a].number, actionp[st,a]))
- _vf.write(" ! reduce/reduce conflict for %s resolved using rule %d (%s).\n" % (a,actionp[st,a].number, actionp[st,a]))
- else:
- print "Unknown conflict in state %d" % st
- else:
- action[st,a] = -p.number
- actionp[st,a] = p
- else:
- i = p.lr_index
- a = p.prod[i+1] # Get symbol right after the "."
- if Terminals.has_key(a):
- g = lr0_goto(I,a)
- j = _lr0_cidhash.get(id(g),-1)
- if j >= 0:
- # We are in a shift state
- actlist.append((a,p,"shift and go to state %d" % j))
- r = action.get((st,a),None)
- if r is not None:
- # Whoa have a shift/reduce or shift/shift conflict
- if r > 0:
- if r != j:
- print "Shift/shift conflict in state %d" % st
- elif r < 0:
- # Do a precedence check.
- # - if precedence of reduce rule is higher, we reduce.
- # - if precedence of reduce is same and left assoc, we reduce.
- # - otherwise we shift
- rprec,rlevel = Productions[actionp[st,a].number].prec
- sprec,slevel = Precedence.get(a,('right',0))
- if (slevel > rlevel) or ((slevel == rlevel) and (rprec != 'left')):
- # We decide to shift here... highest precedence to shift
- action[st,a] = j
- actionp[st,a] = p
- if not slevel and not rlevel:
- n_srconflict += 1
- _vfc.write("shift/reduce conflict in state %d resolved as shift.\n" % st)
- _vf.write(" ! shift/reduce conflict for %s resolved as shift.\n" % a)
- elif (slevel == rlevel) and (rprec == 'nonassoc'):
- action[st,a] = None
- else:
- # Hmmm. Guess we'll keep the reduce
- if not slevel and not rlevel:
- n_srconflict +=1
- _vfc.write("shift/reduce conflict in state %d resolved as reduce.\n" % st)
- _vf.write(" ! shift/reduce conflict for %s resolved as reduce.\n" % a)
-
- else:
- print "Unknown conflict in state %d" % st
- else:
- action[st,a] = j
- actionp[st,a] = p
-
- except StandardError,e:
- raise YaccError, "Hosed in slr_parse_table", e
-
- # Print the actions associated with each terminal
- if yaccdebug:
- for a,p,m in actlist:
- if action.has_key((st,a)):
- if p is actionp[st,a]:
- _vf.write(" %-15s %s\n" % (a,m))
- _vf.write("\n")
- for a,p,m in actlist:
- if action.has_key((st,a)):
- if p is not actionp[st,a]:
- _vf.write(" ! %-15s [ %s ]\n" % (a,m))
-
- # Construct the goto table for this state
- if yaccdebug:
- _vf.write("\n")
- nkeys = { }
- for ii in I:
- for s in ii.usyms:
- if Nonterminals.has_key(s):
- nkeys[s] = None
- for n in nkeys.keys():
- g = lr0_goto(I,n)
- j = _lr0_cidhash.get(id(g),-1)
- if j >= 0:
- goto[st,n] = j
- if yaccdebug:
- _vf.write(" %-15s shift and go to state %d\n" % (n,j))
-
- st += 1
-
- if n_srconflict == 1:
- print "yacc: %d shift/reduce conflict" % n_srconflict
- if n_srconflict > 1:
- print "yacc: %d shift/reduce conflicts" % n_srconflict
- if n_rrconflict == 1:
- print "yacc: %d reduce/reduce conflict" % n_rrconflict
- if n_rrconflict > 1:
- print "yacc: %d reduce/reduce conflicts" % n_rrconflict
-
-
-# -----------------------------------------------------------------------------
-# ==== LALR(1) Parsing ====
-# **** UNFINISHED! 6/16/01
-# -----------------------------------------------------------------------------
-
-
-# Compute the lr1_closure of a set I. I is a list of tuples (p,a) where
-# p is a LR0 item and a is a terminal
-
-_lr1_add_count = 0
-
-def lr1_closure(I):
- global _lr1_add_count
-
- _lr1_add_count += 1
-
- J = I[:]
-
- # Loop over items (p,a) in I.
- ji = 0
- while ji < len(J):
- p,a = J[ji]
- # p = [ A -> alpha . B beta]
-
- # For each production B -> gamma
- for B in p.lr1_after:
- f = tuple(p.lr1_beta + (a,))
-
- # For each terminal b in first(Beta a)
- for b in first(f):
- # Check if (B -> . gamma, b) is in J
- # Only way this can happen is if the add count mismatches
- pn = B.lr_next
- if pn.lr_added.get(b,0) == _lr1_add_count: continue
- pn.lr_added[b] = _lr1_add_count
- J.append((pn,b))
- ji += 1
-
- return J
-
-def lalr_parse_table():
-
- # Compute some lr1 information about all of the productions
- for p in LRitems:
- try:
- after = p.prod[p.lr_index + 1]
- p.lr1_after = Prodnames[after]
- p.lr1_beta = p.prod[p.lr_index + 2:]
- except LookupError:
- p.lr1_after = [ ]
- p.lr1_beta = [ ]
- p.lr_added = { }
-
- # Compute the LR(0) items
- C = lr0_items()
- CK = []
- for I in C:
- CK.append(lr0_kernel(I))
-
- print CK
-
-# -----------------------------------------------------------------------------
-# ==== LR Utility functions ====
-# -----------------------------------------------------------------------------
-
-# -----------------------------------------------------------------------------
-# _lr_write_tables()
-#
-# This function writes the LR parsing tables to a file
-# -----------------------------------------------------------------------------
-
-def lr_write_tables(modulename=tab_module):
- filename = modulename + ".py"
- try:
- f = open(filename,"w")
-
- f.write("""
-# %s
-# This file is automatically generated. Do not edit.
-
-_lr_method = %s
-
-_lr_signature = %s
-""" % (filename, repr(_lr_method), repr(Signature.digest())))
-
- # Change smaller to 0 to go back to original tables
- smaller = 1
-
- # Factor out names to try and make smaller
- if smaller:
- items = { }
-
- for k,v in _lr_action.items():
- i = items.get(k[1])
- if not i:
- i = ([],[])
- items[k[1]] = i
- i[0].append(k[0])
- i[1].append(v)
-
- f.write("\n_lr_action_items = {")
- for k,v in items.items():
- f.write("%r:([" % k)
- for i in v[0]:
- f.write("%r," % i)
- f.write("],[")
- for i in v[1]:
- f.write("%r," % i)
-
- f.write("]),")
- f.write("}\n")
-
- f.write("""
-_lr_action = { }
-for _k, _v in _lr_action_items.items():
- for _x,_y in zip(_v[0],_v[1]):
- _lr_action[(_x,_k)] = _y
-del _lr_action_items
-""")
-
- else:
- f.write("\n_lr_action = { ");
- for k,v in _lr_action.items():
- f.write("(%r,%r):%r," % (k[0],k[1],v))
- f.write("}\n");
-
- if smaller:
- # Factor out names to try and make smaller
- items = { }
-
- for k,v in _lr_goto.items():
- i = items.get(k[1])
- if not i:
- i = ([],[])
- items[k[1]] = i
- i[0].append(k[0])
- i[1].append(v)
-
- f.write("\n_lr_goto_items = {")
- for k,v in items.items():
- f.write("%r:([" % k)
- for i in v[0]:
- f.write("%r," % i)
- f.write("],[")
- for i in v[1]:
- f.write("%r," % i)
-
- f.write("]),")
- f.write("}\n")
-
- f.write("""
-_lr_goto = { }
-for _k, _v in _lr_goto_items.items():
- for _x,_y in zip(_v[0],_v[1]):
- _lr_goto[(_x,_k)] = _y
-del _lr_goto_items
-""")
- else:
- f.write("\n_lr_goto = { ");
- for k,v in _lr_goto.items():
- f.write("(%r,%r):%r," % (k[0],k[1],v))
- f.write("}\n");
-
- # Write production table
- f.write("_lr_productions = [\n")
- for p in Productions:
- if p:
- if (p.func):
- f.write(" (%r,%d,%r,%r,%d),\n" % (p.name, p.len, p.func.__name__,p.file,p.line))
- else:
- f.write(" (%r,%d,None,None,None),\n" % (p.name, p.len))
- else:
- f.write(" None,\n")
- f.write("]\n")
- f.close()
-
- except IOError,e:
- print "Unable to create '%s'" % filename
- print e
- return
-
-def lr_read_tables(module=tab_module,optimize=0):
- global _lr_action, _lr_goto, _lr_productions, _lr_method
- try:
- exec "import %s as parsetab" % module
-
- if (optimize) or (Signature.digest() == parsetab._lr_signature):
- _lr_action = parsetab._lr_action
- _lr_goto = parsetab._lr_goto
- _lr_productions = parsetab._lr_productions
- _lr_method = parsetab._lr_method
- return 1
- else:
- return 0
-
- except (ImportError,AttributeError):
- return 0
-
-# -----------------------------------------------------------------------------
-# yacc(module)
-#
-# Build the parser module
-# -----------------------------------------------------------------------------
-
-def yacc(method=default_lr, debug=yaccdebug, module=None, tabmodule=tab_module, start=None, check_recursion=1, optimize=0):
- global yaccdebug
- yaccdebug = debug
-
- initialize_vars()
- files = { }
- error = 0
-
- # Add starting symbol to signature
- if start:
- Signature.update(start)
-
- # Try to figure out what module we are working with
- if module:
- # User supplied a module object.
- if not isinstance(module, types.ModuleType):
- raise ValueError,"Expected a module"
-
- ldict = module.__dict__
-
- else:
- # No module given. We might be able to get information from the caller.
- # Throw an exception and unwind the traceback to get the globals
-
- try:
- raise RuntimeError
- except RuntimeError:
- e,b,t = sys.exc_info()
- f = t.tb_frame
- f = f.f_back # Walk out to our calling function
- ldict = f.f_globals # Grab its globals dictionary
-
- # If running in optimized mode. We're going to
-
- if (optimize and lr_read_tables(tabmodule,1)):
- # Read parse table
- del Productions[:]
- for p in _lr_productions:
- if not p:
- Productions.append(None)
- else:
- m = MiniProduction()
- m.name = p[0]
- m.len = p[1]
- m.file = p[3]
- m.line = p[4]
- if p[2]:
- m.func = ldict[p[2]]
- Productions.append(m)
-
- else:
- # Get the tokens map
- tokens = ldict.get("tokens",None)
-
- if not tokens:
- raise YaccError,"module does not define a list 'tokens'"
- if not (isinstance(tokens,types.ListType) or isinstance(tokens,types.TupleType)):
- raise YaccError,"tokens must be a list or tuple."
-
- # Check to see if a requires dictionary is defined.
- requires = ldict.get("require",None)
- if requires:
- if not (isinstance(requires,types.DictType)):
- raise YaccError,"require must be a dictionary."
-
- for r,v in requires.items():
- try:
- if not (isinstance(v,types.ListType)):
- raise TypeError
- v1 = [x.split(".") for x in v]
- Requires[r] = v1
- except StandardError:
- print "Invalid specification for rule '%s' in require. Expected a list of strings" % r
-
-
- # Build the dictionary of terminals. We a record a 0 in the
- # dictionary to track whether or not a terminal is actually
- # used in the grammar
-
- if 'error' in tokens:
- print "yacc: Illegal token 'error'. Is a reserved word."
- raise YaccError,"Illegal token name"
-
- for n in tokens:
- if Terminals.has_key(n):
- print "yacc: Warning. Token '%s' multiply defined." % n
- Terminals[n] = [ ]
-
- Terminals['error'] = [ ]
-
- # Get the precedence map (if any)
- prec = ldict.get("precedence",None)
- if prec:
- if not (isinstance(prec,types.ListType) or isinstance(prec,types.TupleType)):
- raise YaccError,"precedence must be a list or tuple."
- add_precedence(prec)
- Signature.update(repr(prec))
-
- for n in tokens:
- if not Precedence.has_key(n):
- Precedence[n] = ('right',0) # Default, right associative, 0 precedence
-
- # Look for error handler
- ef = ldict.get('p_error',None)
- if ef:
- if not isinstance(ef,types.FunctionType):
- raise YaccError,"'p_error' defined, but is not a function."
- eline = ef.func_code.co_firstlineno
- efile = ef.func_code.co_filename
- files[efile] = None
-
- if (ef.func_code.co_argcount != 1):
- raise YaccError,"%s:%d: p_error() requires 1 argument." % (efile,eline)
- global Errorfunc
- Errorfunc = ef
- else:
- print "yacc: Warning. no p_error() function is defined."
-
- # Get the list of built-in functions with p_ prefix
- symbols = [ldict[f] for f in ldict.keys()
- if (isinstance(ldict[f],types.FunctionType) and ldict[f].__name__[:2] == 'p_'
- and ldict[f].__name__ != 'p_error')]
-
- # Check for non-empty symbols
- if len(symbols) == 0:
- raise YaccError,"no rules of the form p_rulename are defined."
-
- # Sort the symbols by line number
- symbols.sort(lambda x,y: cmp(x.func_code.co_firstlineno,y.func_code.co_firstlineno))
-
- # Add all of the symbols to the grammar
- for f in symbols:
- if (add_function(f)) < 0:
- error += 1
- else:
- files[f.func_code.co_filename] = None
-
- # Make a signature of the docstrings
- for f in symbols:
- if f.__doc__:
- Signature.update(f.__doc__)
-
- lr_init_vars()
-
- if error:
- raise YaccError,"Unable to construct parser."
-
- if not lr_read_tables(tabmodule):
-
- # Validate files
- for filename in files.keys():
- if not validate_file(filename):
- error = 1
-
- # Validate dictionary
- validate_dict(ldict)
-
- if start and not Prodnames.has_key(start):
- raise YaccError,"Bad starting symbol '%s'" % start
-
- augment_grammar(start)
- error = verify_productions(cycle_check=check_recursion)
- otherfunc = [ldict[f] for f in ldict.keys()
- if (isinstance(ldict[f],types.FunctionType) and ldict[f].__name__[:2] != 'p_')]
-
- if error:
- raise YaccError,"Unable to construct parser."
-
- build_lritems()
- compute_first1()
- compute_follow(start)
-
- if method == 'SLR':
- slr_parse_table()
- elif method == 'LALR1':
- lalr_parse_table()
- return
- else:
- raise YaccError, "Unknown parsing method '%s'" % method
-
- lr_write_tables(tabmodule)
-
- if yaccdebug:
- try:
- f = open(debug_file,"w")
- f.write(_vfc.getvalue())
- f.write("\n\n")
- f.write(_vf.getvalue())
- f.close()
- except IOError,e:
- print "yacc: can't create '%s'" % debug_file,e
-
- # Made it here. Create a parser object and set up its internal state.
- # Set global parse() method to bound method of parser object.
-
- p = Parser("xyzzy")
- p.productions = Productions
- p.errorfunc = Errorfunc
- p.action = _lr_action
- p.goto = _lr_goto
- p.method = _lr_method
- p.require = Requires
-
- global parse
- parse = p.parse
-
- # Clean up all of the globals we created
- if (not optimize):
- yacc_cleanup()
- return p
-
-# yacc_cleanup function. Delete all of the global variables
-# used during table construction
-
-def yacc_cleanup():
- global _lr_action, _lr_goto, _lr_method, _lr_goto_cache
- del _lr_action, _lr_goto, _lr_method, _lr_goto_cache
-
- global Productions, Prodnames, Prodmap, Terminals
- global Nonterminals, First, Follow, Precedence, LRitems
- global Errorfunc, Signature, Requires
-
- del Productions, Prodnames, Prodmap, Terminals
- del Nonterminals, First, Follow, Precedence, LRitems
- del Errorfunc, Signature, Requires
-
- global _vf, _vfc
- del _vf, _vfc
-
-
-# Stub that raises an error if parsing is attempted without first calling yacc()
-def parse(*args,**kwargs):
- raise YaccError, "yacc: No parser built with yacc()"
-