lex.py - ply - PLY (Python Lex-Yacc) - Google Project Hosting

Source path: svn/ trunk/ ply/ lex.py

‹r80

r86

# -----------------------------------------------------------------------------
# ply: lex.py
#
# Copyright (C) 2001-2009,
# David M. Beazley (Dabeaz LLC)
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
# 
# * Redistributions of source code must retain the above copyright notice,
#   this list of conditions and the following disclaimer.  
# * Redistributions in binary form must reproduce the above copyright notice, 
#   this list of conditions and the following disclaimer in the documentation
#   and/or other materials provided with the distribution.  
# * Neither the name of the David Beazley or Dabeaz LLC may be used to
#   endorse or promote products derived from this software without
#  specific prior written permission. 
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# -----------------------------------------------------------------------------

__version__    = "3.3"
__tabversion__ = "3.2"       # Version of table file used

import re, sys, types, copy, os

# This tuple contains known string types
try:
    # Python 2.6
    StringTypes = (types.StringType, types.UnicodeType)
except AttributeError:
    # Python 3.0
    StringTypes = (str, bytes)

# Extract the code attribute of a function. Different implementations
# are for Python 2/3 compatibility.

if sys.version_info[0] < 3:
    def func_code(f):
        return f.func_code
else:
    def func_code(f):
        return f.__code__

# This regular expression is used to match valid token names
_is_identifier = re.compile(r'^[a-zA-Z0-9_]+$')

# Exception thrown when invalid token encountered and no default error
# handler is defined.

class LexError(Exception):
    def __init__(self,message,s):
         self.args = (message,)
         self.text = s

# Token class.  This class is used to represent the tokens produced.
class LexToken(object):
    def __str__(self):
        return "LexToken(%s,%r,%d,%d)" % (self.type,self.value,self.lineno,self.lexpos)
    def __repr__(self):
        return str(self)

# This object is a stand-in for a logging object created by the 
# logging module.  

class PlyLogger(object):
    def __init__(self,f):
        self.f = f
    def critical(self,msg,*args,**kwargs):
        self.f.write((msg % args) + "\n")

    def warning(self,msg,*args,**kwargs):
        self.f.write("WARNING: "+ (msg % args) + "\n")

    def error(self,msg,*args,**kwargs):
        self.f.write("ERROR: " + (msg % args) + "\n")

    info = critical
    debug = critical

# Null logger is used when no output is generated. Does nothing.
class NullLogger(object):
    def __getattribute__(self,name):
        return self
    def __call__(self,*args,**kwargs):
        return self

# -----------------------------------------------------------------------------
#                        === Lexing Engine ===
#
# The following Lexer class implements the lexer runtime.   There are only
# a few public methods and attributes:
#
#    input()          -  Store a new string in the lexer
#    token()          -  Get the next token
#    clone()          -  Clone the lexer
#
#    lineno           -  Current line number
#    lexpos           -  Current position in the input string
# -----------------------------------------------------------------------------

class Lexer:
    def __init__(self):
        self.lexre = None             # Master regular expression. This is a list of
                                      # tuples (re,findex) where re is a compiled
                                      # regular expression and findex is a list
                                      # mapping regex group numbers to rules
        self.lexretext = None         # Current regular expression strings
        self.lexstatere = {}          # Dictionary mapping lexer states to master regexs
        self.lexstateretext = {}      # Dictionary mapping lexer states to regex strings
        self.lexstaterenames = {}     # Dictionary mapping lexer states to symbol names
        self.lexstate = "INITIAL"     # Current lexer state
        self.lexstatestack = []       # Stack of lexer states
        self.lexstateinfo = None      # State information
        self.lexstateignore = {}      # Dictionary of ignored characters for each state
        self.lexstateerrorf = {}      # Dictionary of error functions for each state
        self.lexreflags = 0           # Optional re compile flags
        self.lexdata = None           # Actual input data (as a string)
        self.lexpos = 0               # Current position in input text
        self.lexlen = 0               # Length of the input text
        self.lexerrorf = None         # Error rule (if any)
        self.lextokens = None         # List of valid tokens
        self.lexignore = ""           # Ignored characters
        self.lexliterals = ""         # Literal characters that can be passed through
        self.lexmodule = None         # Module
        self.lineno = 1               # Current line number
        self.lexoptimize = 0          # Optimized mode

    def clone(self,object=None):
        c = copy.copy(self)

        # If the object parameter has been supplied, it means we are attaching the
        # lexer to a new object.  In this case, we have to rebind all methods in
        # the lexstatere and lexstateerrorf tables.

        if object:
            newtab = { }
            for key, ritem in self.lexstatere.items():
                newre = []
                for cre, findex in ritem:
                     newfindex = []
                     for f in findex:
                         if not f or not f[0]:
                             newfindex.append(f)
                             continue
                         newfindex.append((getattr(object,f[0].__name__),f[1]))
                newre.append((cre,newfindex))
                newtab[key] = newre
            c.lexstatere = newtab
            c.lexstateerrorf = { }
            for key, ef in self.lexstateerrorf.items():
                c.lexstateerrorf[key] = getattr(object,ef.__name__)
            c.lexmodule = object
        return c

    # ------------------------------------------------------------
    # writetab() - Write lexer information to a table file
    # ------------------------------------------------------------
    def writetab(self,tabfile,outputdir=""):
        if isinstance(tabfile,types.ModuleType):
            return
        basetabfilename = tabfile.split(".")[-1]
        filename = os.path.join(outputdir,basetabfilename)+".py"
        tf = open(filename,"w")
        tf.write("# %s.py. This file automatically created by PLY (version %s). Don't edit!\n" % (tabfile,__version__))
        tf.write("_tabversion   = %s\n" % repr(__version__))
        tf.write("_lextokens    = %s\n" % repr(self.lextokens))
        tf.write("_lexreflags   = %s\n" % repr(self.lexreflags))
        tf.write("_lexliterals  = %s\n" % repr(self.lexliterals))
        tf.write("_lexstateinfo = %s\n" % repr(self.lexstateinfo))

        tabre = { }
        # Collect all functions in the initial state
        initial = self.lexstatere["INITIAL"]
        initialfuncs = []
        for part in initial:
            for f in part[1]:
                if f and f[0]:
                    initialfuncs.append(f)

        for key, lre in self.lexstatere.items():
             titem = []
             for i in range(len(lre)):
                  titem.append((self.lexstateretext[key][i],_funcs_to_names(lre[i][1],self.lexstaterenames[key][i])))
             tabre[key] = titem

        tf.write("_lexstatere   = %s\n" % repr(tabre))
        tf.write("_lexstateignore = %s\n" % repr(self.lexstateignore))

        taberr = { }
        for key, ef in self.lexstateerrorf.items():
             if ef:
                  taberr[key] = ef.__name__
             else:
                  taberr[key] = None
        tf.write("_lexstateerrorf = %s\n" % repr(taberr))
        tf.close()

    # ------------------------------------------------------------
    # readtab() - Read lexer information from a tab file
    # ------------------------------------------------------------
    def readtab(self,tabfile,fdict):
        if isinstance(tabfile,types.ModuleType):
            lextab = tabfile
        else:
            if sys.version_info[0] < 3:
                exec("import %s as lextab" % tabfile)
            else:
                env = { }
                exec("import %s as lextab" % tabfile, env,env)
                lextab = env['lextab']

        if getattr(lextab,"_tabversion","0.0") != __version__:
            raise ImportError("Inconsistent PLY version")

        self.lextokens      = lextab._lextokens
        self.lexreflags     = lextab._lexreflags
        self.lexliterals    = lextab._lexliterals
        self.lexstateinfo   = lextab._lexstateinfo
        self.lexstateignore = lextab._lexstateignore
        self.lexstatere     = { }
        self.lexstateretext = { }
        for key,lre in lextab._lexstatere.items():
             titem = []
             txtitem = []
             for i in range(len(lre)):
                  titem.append((re.compile(lre[i][0],lextab._lexreflags | re.VERBOSE),_names_to_funcs(lre[i][1],fdict)))
                  txtitem.append(lre[i][0])
             self.lexstatere[key] = titem
             self.lexstateretext[key] = txtitem
        self.lexstateerrorf = { }
        for key,ef in lextab._lexstateerrorf.items():
             self.lexstateerrorf[key] = fdict[ef]
        self.begin('INITIAL')

    # ------------------------------------------------------------
    # input() - Push a new string into the lexer
    # ------------------------------------------------------------
    def input(self,s):
        # Pull off the first character to see if s looks like a string
        c = s[:1]
        if not isinstance(c,StringTypes):
            raise ValueError("Expected a string")
        self.lexdata = s
        self.lexpos = 0
        self.lexlen = len(s)

    # ------------------------------------------------------------
    # begin() - Changes the lexing state
    # ------------------------------------------------------------
    def begin(self,state):
        if not state in self.lexstatere:
            raise ValueError("Undefined state")
        self.lexre = self.lexstatere[state]
        self.lexretext = self.lexstateretext[state]
        self.lexignore = self.lexstateignore.get(state,"")
        self.lexerrorf = self.lexstateerrorf.get(state,None)
        self.lexstate = state

    # ------------------------------------------------------------
    # push_state() - Changes the lexing state and saves old on stack
    # ------------------------------------------------------------
    def push_state(self,state):
        self.lexstatestack.append(self.lexstate)
        self.begin(state)

    # ------------------------------------------------------------
    # pop_state() - Restores the previous state
    # ------------------------------------------------------------
    def pop_state(self):
        self.begin(self.lexstatestack.pop())

    # ------------------------------------------------------------
    # current_state() - Returns the current lexing state
    # ------------------------------------------------------------
    def current_state(self):
        return self.lexstate

    # ------------------------------------------------------------
    # skip() - Skip ahead n characters
    # ------------------------------------------------------------
    def skip(self,n):
        self.lexpos += n

    # ------------------------------------------------------------
    # opttoken() - Return the next token from the Lexer
    #
    # Note: This function has been carefully implemented to be as fast
    # as possible.  Don't make changes unless you really know what
    # you are doing
    # ------------------------------------------------------------
    def token(self):
        # Make local copies of frequently referenced attributes
        lexpos    = self.lexpos
        lexlen    = self.lexlen
        lexignore = self.lexignore
        lexdata   = self.lexdata

        while lexpos < lexlen:
            # This code provides some short-circuit code for whitespace, tabs, and other ignored characters
            if lexdata[lexpos] in lexignore:
                lexpos += 1
                continue

            # Look for a regular expression match
            for lexre,lexindexfunc in self.lexre:
                m = lexre.match(lexdata,lexpos)
                if not m: continue

                # Create a token for return
                tok = LexToken()
                tok.value = m.group()
                tok.lineno = self.lineno
                tok.lexpos = lexpos

                i = m.lastindex
                func,tok.type = lexindexfunc[i]

                if not func:
                   # If no token type was set, it's an ignored token
                   if tok.type:
                      self.lexpos = m.end()
                      return tok
                   else:
                      lexpos = m.end()
                      break

                lexpos = m.end()

                # If token is processed by a function, call it

                tok.lexer = self      # Set additional attributes useful in token rules
                self.lexmatch = m
                self.lexpos = lexpos

                newtok = func(tok)

                # Every function must return a token, if nothing, we just move to next token
                if not newtok:
                    lexpos    = self.lexpos         # This is here in case user has updated lexpos.
                    lexignore = self.lexignore      # This is here in case there was a state change
                    break

                # Verify type of the token.  If not in the token map, raise an error
                if not self.lexoptimize:
                    if not newtok.type in self.lextokens:
                        raise LexError("%s:%d: Rule '%s' returned an unknown token type '%s'" % (
                            func_code(func).co_filename, func_code(func).co_firstlineno,
                            func.__name__, newtok.type),lexdata[lexpos:])

                return newtok
            else:
                # No match, see if in literals
                if lexdata[lexpos] in self.lexliterals:
                    tok = LexToken()
                    tok.value = lexdata[lexpos]
                    tok.lineno = self.lineno
                    tok.type = tok.value
                    tok.lexpos = lexpos
                    self.lexpos = lexpos + 1
                    return tok

                # No match. Call t_error() if defined.
                if self.lexerrorf:
                    tok = LexToken()
                    tok.value = self.lexdata[lexpos:]
                    tok.lineno = self.lineno
                    tok.type = "error"
                    tok.lexer = self
                    tok.lexpos = lexpos
                    self.lexpos = lexpos
                    newtok = self.lexerrorf(tok)
                    if lexpos == self.lexpos:
                        # Error method didn't change text position at all. This is an error.
                        raise LexError("Scanning error. Illegal character '%s'" % (lexdata[lexpos]), lexdata[lexpos:])
                    lexpos = self.lexpos
                    if not newtok: continue
                    return newtok

                self.lexpos = lexpos
                raise LexError("Illegal character '%s' at index %d" % (lexdata[lexpos],lexpos), lexdata[lexpos:])

        self.lexpos = lexpos + 1
        if self.lexdata is None:
             raise RuntimeError("No input string given with input()")
        return None

    # Iterator interface
    def __iter__(self):
        return self

    def next(self):
        t = self.token()
        if t is None:
            raise StopIteration
        return t

    __next__ = next

# -----------------------------------------------------------------------------
#                           ==== Lex Builder ===
#
# The functions and classes below are used to collect lexing information
# and build a Lexer object from it.
# -----------------------------------------------------------------------------

# -----------------------------------------------------------------------------
# get_caller_module_dict()
#
# This function returns a dictionary containing all of the symbols defined within
# a caller further down the call stack.  This is used to get the environment
# associated with the yacc() call if none was provided.
# -----------------------------------------------------------------------------

def get_caller_module_dict(levels):
    try:
        raise RuntimeError
    except RuntimeError:
        e,b,t = sys.exc_info()
        f = t.tb_frame
        while levels > 0:
            f = f.f_back                   
            levels -= 1
        ldict = f.f_globals.copy()
        if f.f_globals != f.f_locals:
            ldict.update(f.f_locals)

        return ldict

# -----------------------------------------------------------------------------
# _funcs_to_names()
#
# Given a list of regular expression functions, this converts it to a list
# suitable for output to a table file
# -----------------------------------------------------------------------------

def _funcs_to_names(funclist,namelist):
    result = []
    for f,name in zip(funclist,namelist):
         if f and f[0]:
             result.append((name, f[1]))
         else:
             result.append(f)
    return result

# -----------------------------------------------------------------------------
# _names_to_funcs()
#
# Given a list of regular expression function names, this converts it back to
# functions.
# -----------------------------------------------------------------------------

def _names_to_funcs(namelist,fdict):
     result = []
     for n in namelist:
          if n and n[0]:
              result.append((fdict[n[0]],n[1]))
          else:
              result.append(n)
     return result

# -----------------------------------------------------------------------------
# _form_master_re()
#
# This function takes a list of all of the regex components and attempts to
# form the master regular expression.  Given limitations in the Python re
# module, it may be necessary to break the master regex into separate expressions.
# -----------------------------------------------------------------------------

def _form_master_re(relist,reflags,ldict,toknames):
    if not relist: return []
    regex = "|".join(relist)
    try:
        lexre = re.compile(regex,re.VERBOSE | reflags)

        # Build the index to function map for the matching engine
        lexindexfunc = [ None ] * (max(lexre.groupindex.values())+1)
        lexindexnames = lexindexfunc[:]

        for f,i in lexre.groupindex.items():
            handle = ldict.get(f,None)
            if type(handle) in (types.FunctionType, types.MethodType):
                lexindexfunc[i] = (handle,toknames[f])
                lexindexnames[i] = f
            elif handle is not None:
                lexindexnames[i] = f
                if f.find("ignore_") > 0:
                    lexindexfunc[i] = (None,None)
                else:
                    lexindexfunc[i] = (None, toknames[f])
        
        return [(lexre,lexindexfunc)],[regex],[lexindexnames]
    except Exception:
        m = int(len(relist)/2)
        if m == 0: m = 1
        llist, lre, lnames = _form_master_re(relist[:m],reflags,ldict,toknames)
        rlist, rre, rnames = _form_master_re(relist[m:],reflags,ldict,toknames)
        return llist+rlist, lre+rre, lnames+rnames

# -----------------------------------------------------------------------------
# def _statetoken(s,names)
#
# Given a declaration name s of the form "t_" and a dictionary whose keys are
# state names, this function returns a tuple (states,tokenname) where states
# is a tuple of state names and tokenname is the name of the token.  For example,
# calling this with s = "t_foo_bar_SPAM" might return (('foo','bar'),'SPAM')
# -----------------------------------------------------------------------------

def _statetoken(s,names):
    nonstate = 1
    parts = s.split("_")
    for i in range(1,len(parts)):
         if not parts[i] in names and parts[i] != 'ANY': break
    if i > 1:
       states = tuple(parts[1:i])
    else:
       states = ('INITIAL',)

    if 'ANY' in states:
       states = tuple(names)

    tokenname = "_".join(parts[i:])
    return (states,tokenname)


# -----------------------------------------------------------------------------
# LexerReflect()
#
# This class represents information needed to build a lexer as extracted from a
# user's input file.
# -----------------------------------------------------------------------------
class LexerReflect(object):
    def __init__(self,ldict,log=None,reflags=0):
        self.ldict      = ldict
        self.error_func = None
        self.tokens     = []
        self.reflags    = reflags
        self.stateinfo  = { 'INITIAL' : 'inclusive'}
        self.files      = {}
        self.error      = 0

        if log is None:
            self.log = PlyLogger(sys.stderr)
        else:
            self.log = log

    # Get all of the basic information
    def get_all(self):
        self.get_tokens()
        self.get_literals()
        self.get_states()
        self.get_rules()
        
    # Validate all of the information
    def validate_all(self):
        self.validate_tokens()
        self.validate_literals()
        self.validate_rules()
        return self.error

    # Get the tokens map
    def get_tokens(self):
        tokens = self.ldict.get("tokens",None)
        if not tokens:
            self.log.error("No token list is defined")
            self.error = 1
            return

        if not isinstance(tokens,(list, tuple)):
            self.log.error("tokens must be a list or tuple")
            self.error = 1
            return
        
        if not tokens:
            self.log.error("tokens is empty")
            self.error = 1
            return

        self.tokens = tokens

    # Validate the tokens
    def validate_tokens(self):
        terminals = {}
        for n in self.tokens:
            if not _is_identifier.match(n):
                self.log.error("Bad token name '%s'",n)
                self.error = 1
            if n in terminals:
                self.log.warning("Token '%s' multiply defined", n)
            terminals[n] = 1

    # Get the literals specifier
    def get_literals(self):
        self.literals = self.ldict.get("literals","")

    # Validate literals
    def validate_literals(self):
        try:
            for c in self.literals:
                if not isinstance(c,StringTypes) or len(c) > 1:
                    self.log.error("Invalid literal %s. Must be a single character", repr(c))
                    self.error = 1
                    continue

        except TypeError:
            self.log.error("Invalid literals specification. literals must be a sequence of characters")
            self.error = 1

    def get_states(self):
        self.states = self.ldict.get("states",None)
        # Build statemap
        if self.states:
             if not isinstance(self.states,(tuple,list)):
                  self.log.error("states must be defined as a tuple or list")
                  self.error = 1
             else:
                  for s in self.states:
                        if not isinstance(s,tuple) or len(s) != 2:
                               self.log.error("Invalid state specifier %s. Must be a tuple (statename,'exclusive|inclusive')",repr(s))
                               self.error = 1
                               continue
                        name, statetype = s
                        if not isinstance(name,StringTypes):
                               self.log.error("State name %s must be a string", repr(name))
                               self.error = 1
                               continue
                        if not (statetype == 'inclusive' or statetype == 'exclusive'):
                               self.log.error("State type for state %s must be 'inclusive' or 'exclusive'",name)
                               self.error = 1
                               continue
                        if name in self.stateinfo:
                               self.log.error("State '%s' already defined",name)
                               self.error = 1
                               continue
                        self.stateinfo[name] = statetype

    # Get all of the symbols with a t_ prefix and sort them into various
    # categories (functions, strings, error functions, and ignore characters)

    def get_rules(self):
        tsymbols = [f for f in self.ldict if f[:2] == 't_' ]

        # Now build up a list of functions and a list of strings

        self.toknames = { }        # Mapping of symbols to token names
        self.funcsym =  { }        # Symbols defined as functions
        self.strsym =   { }        # Symbols defined as strings
        self.ignore   = { }        # Ignore strings by state
        self.errorf   = { }        # Error functions by state

        for s in self.stateinfo:
             self.funcsym[s] = []
             self.strsym[s] = []

        if len(tsymbols) == 0:
            self.log.error("No rules of the form t_rulename are defined")
            self.error = 1
            return

        for f in tsymbols:
            t = self.ldict[f]
            states, tokname = _statetoken(f,self.stateinfo)
            self.toknames[f] = tokname

            if hasattr(t,"__call__"):
                if tokname == 'error':
                    for s in states:
                        self.errorf[s] = t
                elif tokname == 'ignore':
                    line = func_code(t).co_firstlineno
                    file = func_code(t).co_filename
                    self.log.error("%s:%d: Rule '%s' must be defined as a string",file,line,t.__name__)
                    self.error = 1
                else:
                    for s in states: 
                        self.funcsym[s].append((f,t))
            elif isinstance(t, StringTypes):
                if tokname == 'ignore':
                    for s in states:
                        self.ignore[s] = t
                    if "\\" in t:
                        self.log.warning("%s contains a literal backslash '\\'",f)

                elif tokname == 'error':
                    self.log.error("Rule '%s' must be defined as a function", f)
                    self.error = 1
                else:
                    for s in states: 
                        self.strsym[s].append((f,t))
            else:
                self.log.error("%s not defined as a function or string", f)
                self.error = 1

        # Sort the functions by line number
        for f in self.funcsym.values():
            if sys.version_info[0] < 3:
                f.sort(lambda x,y: cmp(func_code(x[1]).co_firstlineno,func_code(y[1]).co_firstlineno))
            else:
                # Python 3.0
                f.sort(key=lambda x: func_code(x[1]).co_firstlineno)

        # Sort the strings by regular expression length
        for s in self.strsym.values():
            if sys.version_info[0] < 3:
                s.sort(lambda x,y: (len(x[1]) < len(y[1])) - (len(x[1]) > len(y[1])))
            else:
                # Python 3.0
                s.sort(key=lambda x: len(x[1]),reverse=True)

    # Validate all of the t_rules collected 
    def validate_rules(self):
        for state in self.stateinfo:
            # Validate all rules defined by functions

            

            for fname, f in self.funcsym[state]:
                line = func_code(f).co_firstlineno
                file = func_code(f).co_filename
                self.files[file] = 1

                tokname = self.toknames[fname]
                if isinstance(f, types.MethodType):
                    reqargs = 2
                else:
                    reqargs = 1
                nargs = func_code(f).co_argcount
                if nargs > reqargs:
                    self.log.error("%s:%d: Rule '%s' has too many arguments",file,line,f.__name__)
                    self.error = 1
                    continue

                if nargs < reqargs:
                    self.log.error("%s:%d: Rule '%s' requires an argument", file,line,f.__name__)
                    self.error = 1
                    continue

                if not f.__doc__:
                    self.log.error("%s:%d: No regular expression defined for rule '%s'",file,line,f.__name__)
                    self.error = 1
                    continue

                try:
                    c = re.compile("(?P<%s>%s)" % (fname,f.__doc__), re.VERBOSE | self.reflags)
                    if c.match(""):
                        self.log.error("%s:%d: Regular expression for rule '%s' matches empty string", file,line,f.__name__)
                        self.error = 1
                except re.error:
                    _etype, e, _etrace = sys.exc_info()
                    self.log.error("%s:%d: Invalid regular expression for rule '%s'. %s", file,line,f.__name__,e)
                    if '#' in f.__doc__:
                        self.log.error("%s:%d. Make sure '#' in rule '%s' is escaped with '\\#'",file,line, f.__name__)
                    self.error = 1

            # Validate all rules defined by strings
            for name,r in self.strsym[state]:
                tokname = self.toknames[name]
                if tokname == 'error':
                    self.log.error("Rule '%s' must be defined as a function", name)
                    self.error = 1
                    continue

                if not tokname in self.tokens and tokname.find("ignore_") < 0:
                    self.log.error("Rule '%s' defined for an unspecified token %s",name,tokname)
                    self.error = 1
                    continue

                try:
                    c = re.compile("(?P<%s>%s)" % (name,r),re.VERBOSE | self.reflags)
                    if (c.match("")):
                         self.log.error("Regular expression for rule '%s' matches empty string",name)
                         self.error = 1
                except re.error:
                    _etype, e, _etrace = sys.exc_info()
                    self.log.error("Invalid regular expression for rule '%s'. %s",name,e)
                    if '#' in r:
                         self.log.error("Make sure '#' in rule '%s' is escaped with '\\#'",name)
                    self.error = 1

            if not self.funcsym[state] and not self.strsym[state]:
                self.log.error("No rules defined for state '%s'",state)
                self.error = 1

            # Validate the error function
            efunc = self.errorf.get(state,None)
            if efunc:
                f = efunc
                line = func_code(f).co_firstlineno
                file = func_code(f).co_filename
                self.files[file] = 1

                if isinstance(f, types.MethodType):
                    reqargs = 2
                else:
                    reqargs = 1
                nargs = func_code(f).co_argcount
                if nargs > reqargs:
                    self.log.error("%s:%d: Rule '%s' has too many arguments",file,line,f.__name__)
                    self.error = 1

                if nargs < reqargs:
                    self.log.error("%s:%d: Rule '%s' requires an argument", file,line,f.__name__)
                    self.error = 1

        for f in self.files:
            self.validate_file(f)


    # -----------------------------------------------------------------------------
    # validate_file()
    #
    # This checks to see if there are duplicated t_rulename() functions or strings
    # in the parser input file.  This is done using a simple regular expression
    # match on each line in the given file.  
    # -----------------------------------------------------------------------------

    def validate_file(self,filename):
        import os.path
        base,ext = os.path.splitext(filename)
        if ext != '.py': return         # No idea what the file is. Return OK

        try:
            f = open(filename)
            lines = f.readlines()
            f.close()
        except IOError:
            return                      # Couldn't find the file.  Don't worry about it

        fre = re.compile(r'\s*def\s+(t_[a-zA-Z_0-9]*)\(')
        sre = re.compile(r'\s*(t_[a-zA-Z_0-9]*)\s*=')

        counthash = { }
        linen = 1
        for l in lines:
            m = fre.match(l)
            if not m:
                m = sre.match(l)
            if m:
                name = m.group(1)
                prev = counthash.get(name)
                if not prev:
                    counthash[name] = linen
                else:
                    self.log.error("%s:%d: Rule %s redefined. Previously defined on line %d",filename,linen,name,prev)
                    self.error = 1
            linen += 1
            
# -----------------------------------------------------------------------------
# lex(module)
#
# Build all of the regular expression rules from definitions in the supplied module
# -----------------------------------------------------------------------------
def lex(module=None,object=None,debug=0,optimize=0,lextab="lextab",reflags=0,nowarn=0,outputdir="", debuglog=None, errorlog=None):
    global lexer
    ldict = None
    stateinfo  = { 'INITIAL' : 'inclusive'}
    lexobj = Lexer()
    lexobj.lexoptimize = optimize
    global token,input

    if errorlog is None:
        errorlog = PlyLogger(sys.stderr)

    if debug:
        if debuglog is None:
            debuglog = PlyLogger(sys.stderr)

    # Get the module dictionary used for the lexer
    if object: module = object

    if module:
        _items = [(k,getattr(module,k)) for k in dir(module)]
        ldict = dict(_items)
    else:
        ldict = get_caller_module_dict(2)

    # Collect parser information from the dictionary
    linfo = LexerReflect(ldict,log=errorlog,reflags=reflags)
    linfo.get_all()
    if not optimize:
        if linfo.validate_all():
            raise SyntaxError("Can't build lexer")

    if optimize and lextab:
        try:
            lexobj.readtab(lextab,ldict)
            token = lexobj.token
            input = lexobj.input
            lexer = lexobj
            return lexobj

        except ImportError:
            pass

    # Dump some basic debugging information
    if debug:
        debuglog.info("lex: tokens   = %r", linfo.tokens)
        debuglog.info("lex: literals = %r", linfo.literals)
        debuglog.info("lex: states   = %r", linfo.stateinfo)

    # Build a dictionary of valid token names
    lexobj.lextokens = { }
    for n in linfo.tokens:
        lexobj.lextokens[n] = 1

    # Get literals specification
    if isinstance(linfo.literals,(list,tuple)):
        lexobj.lexliterals = type(linfo.literals[0])().join(linfo.literals)
    else:
        lexobj.lexliterals = linfo.literals

    # Get the stateinfo dictionary
    stateinfo = linfo.stateinfo

    regexs = { }
    # Build the master regular expressions
    for state in stateinfo:
        regex_list = []

        # Add rules defined by functions first
        for fname, f in linfo.funcsym[state]:
            line = func_code(f).co_firstlineno
            file = func_code(f).co_filename
            regex_list.append("(?P<%s>%s)" % (fname,f.__doc__))
            if debug:
                debuglog.info("lex: Adding rule %s -> '%s' (state '%s')",fname,f.__doc__, state)

        # Now add all of the simple rules
        for name,r in linfo.strsym[state]:
            regex_list.append("(?P<%s>%s)" % (name,r))
            if debug:
                debuglog.info("lex: Adding rule %s -> '%s' (state '%s')",name,r, state)

        regexs[state] = regex_list

    # Build the master regular expressions

    if debug:
        debuglog.info("lex: ==== MASTER REGEXS FOLLOW ====")

    for state in regexs:
        lexre, re_text, re_names = _form_master_re(regexs[state],reflags,ldict,linfo.toknames)
        lexobj.lexstatere[state] = lexre
        lexobj.lexstateretext[state] = re_text
        lexobj.lexstaterenames[state] = re_names
        if debug:
            for i in range(len(re_text)):
                debuglog.info("lex: state '%s' : regex[%d] = '%s'",state, i, re_text[i])

    # For inclusive states, we need to add the regular expressions from the INITIAL state
    for state,stype in stateinfo.items():
        if state != "INITIAL" and stype == 'inclusive':
             lexobj.lexstatere[state].extend(lexobj.lexstatere['INITIAL'])
             lexobj.lexstateretext[state].extend(lexobj.lexstateretext['INITIAL'])
             lexobj.lexstaterenames[state].extend(lexobj.lexstaterenames['INITIAL'])

    lexobj.lexstateinfo = stateinfo
    lexobj.lexre = lexobj.lexstatere["INITIAL"]
    lexobj.lexretext = lexobj.lexstateretext["INITIAL"]
    lexobj.lexreflags = reflags

    # Set up ignore variables
    lexobj.lexstateignore = linfo.ignore
    lexobj.lexignore = lexobj.lexstateignore.get("INITIAL","")

    # Set up error functions
    lexobj.lexstateerrorf = linfo.errorf
    lexobj.lexerrorf = linfo.errorf.get("INITIAL",None)
    if not lexobj.lexerrorf:
        errorlog.warning("No t_error rule is defined")

    # Check state information for ignore and error rules
    for s,stype in stateinfo.items():
        if stype == 'exclusive':
              if not s in linfo.errorf:
                   errorlog.warning("No error rule is defined for exclusive state '%s'", s)
              if not s in linfo.ignore and lexobj.lexignore:
                   errorlog.warning("No ignore rule is defined for exclusive state '%s'", s)
        elif stype == 'inclusive':
              if not s in linfo.errorf:
                   linfo.errorf[s] = linfo.errorf.get("INITIAL",None)
              if not s in linfo.ignore:
                   linfo.ignore[s] = linfo.ignore.get("INITIAL","")

    # Create global versions of the token() and input() functions
    token = lexobj.token
    input = lexobj.input
    lexer = lexobj

    # If in optimize mode, we write the lextab
    if lextab and optimize:
        lexobj.writetab(lextab,outputdir)

    return lexobj

# -----------------------------------------------------------------------------
# runmain()
#
# This runs the lexer as a main program
# -----------------------------------------------------------------------------

def runmain(lexer=None,data=None):
    if not data:
        try:
            filename = sys.argv[1]
            f = open(filename)
            data = f.read()
            f.close()
        except IndexError:
            sys.stdout.write("Reading from standard input (type EOF to end):\n")
            data = sys.stdin.read()

    if lexer:
        _input = lexer.input
    else:
        _input = input
    _input(data)
    if lexer:
        _token = lexer.token
    else:
        _token = token

    while 1:
        tok = _token()
        if not tok: break
        sys.stdout.write("(%s,%r,%d,%d)\n" % (tok.type, tok.value, tok.lineno,tok.lexpos))

# -----------------------------------------------------------------------------
# @TOKEN(regex)
#
# This decorator function can be used to set the regex expression on a function
# when its docstring might need to be set in an alternative way
# -----------------------------------------------------------------------------

def TOKEN(r):
    def set_doc(f):
        if hasattr(r,"__call__"):
            f.__doc__ = r.__doc__
        else:
            f.__doc__ = r
        return f
    return set_doc

# Alternative spelling of the TOKEN decorator
Token = TOKEN

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Change log

r84 by dbeazley on Aug 26, 2009 Diff

A few minor bug fixes

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Older revisions

r80 by dbeazley on Mar 24, 2009 Diff

License change to BSD

r73 by dbeazley on Mar 23, 2009 Diff

Bumped version number

r67 by dbeazley on Feb 7, 2009 Diff

Added nowarn back as an argument to
lex so the API isn't broken.

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