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# -----------------------------------------------------------------------------
# ply: lex.py
#
# Author: David M. Beazley (dave@dabeaz.com)
#
# Copyright (C) 2001-2009, David M. Beazley
#
# 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.
# -----------------------------------------------------------------------------
__version__ = "3.0"
__tabversion__ = "3.0" # 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),_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"]
# 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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