Implemented posix-mode parsing support in shlex.py, as dicussed in

mailing list, and in patch #722686.
This commit is contained in:
Gustavo Niemeyer 2003-04-17 21:31:33 +00:00
parent 84c2b1b9aa
commit 68d8cef89a
4 changed files with 416 additions and 47 deletions

View file

@ -1,28 +1,51 @@
# -*- coding: iso-8859-1 -*-
"""A lexical analyzer class for simple shell-like syntaxes."""
# Module and documentation by Eric S. Raymond, 21 Dec 1998
# Input stacking and error message cleanup added by ESR, March 2000
# push_source() and pop_source() made explicit by ESR, January 2001.
# Posix compliance, split(), string arguments, and
# iterator interface by Gustavo Niemeyer, April 2003.
import os.path
import sys
__all__ = ["shlex"]
from types import StringTypes
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
__all__ = ["shlex", "split"]
class shlex:
"A lexical analyzer class for simple shell-like syntaxes."
def __init__(self, instream=None, infile=None):
def __init__(self, instream=None, infile=None, posix=0):
if type(instream) in StringTypes:
instream = StringIO(instream)
if instream is not None:
self.instream = instream
self.infile = infile
else:
self.instream = sys.stdin
self.infile = None
self.posix = posix
if posix:
self.eof = None
else:
self.eof = ''
self.commenters = '#'
self.wordchars = ('abcdfeghijklmnopqrstuvwxyz'
'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_')
if self.posix:
self.wordchars += ('ßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿ'
'ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞ')
self.whitespace = ' \t\r\n'
self.whitespace_split = 0
self.quotes = '\'"'
self.escape = '\\'
self.escapedquotes = '"'
self.state = ' '
self.pushback = []
self.lineno = 1
@ -42,6 +65,8 @@ class shlex:
def push_source(self, newstream, newfile=None):
"Push an input source onto the lexer's input source stack."
if type(newstream) in StringTypes:
newstream = StringIO(newstream)
self.filestack.insert(0, (self.infile, self.instream, self.lineno))
self.infile = newfile
self.instream = newstream
@ -73,29 +98,31 @@ class shlex:
# No pushback. Get a token.
raw = self.read_token()
# Handle inclusions
while raw == self.source:
spec = self.sourcehook(self.read_token())
if spec:
(newfile, newstream) = spec
self.push_source(newstream, newfile)
raw = self.get_token()
if self.source is not None:
while raw == self.source:
spec = self.sourcehook(self.read_token())
if spec:
(newfile, newstream) = spec
self.push_source(newstream, newfile)
raw = self.get_token()
# Maybe we got EOF instead?
while raw == "":
while raw == self.eof:
if len(self.filestack) == 0:
return ""
return self.eof
else:
self.pop_source()
raw = self.get_token()
# Neither inclusion nor EOF
# Neither inclusion nor EOF
if self.debug >= 1:
if raw:
if raw != self.eof:
print "shlex: token=" + `raw`
else:
print "shlex: token=EOF"
return raw
def read_token(self):
"Read a token from the input stream (no pushback or inclusions)"
quoted = 0
escapedstate = ' '
while 1:
nextchar = self.instream.read(1)
if nextchar == '\n':
@ -113,35 +140,65 @@ class shlex:
elif nextchar in self.whitespace:
if self.debug >= 2:
print "shlex: I see whitespace in whitespace state"
if self.token:
if self.token or (self.posix and quoted):
break # emit current token
else:
continue
elif nextchar in self.commenters:
self.instream.readline()
self.lineno = self.lineno + 1
elif self.posix and nextchar in self.escape:
escapedstate = 'a'
self.state = nextchar
elif nextchar in self.wordchars:
self.token = nextchar
self.state = 'a'
elif nextchar in self.quotes:
self.token = nextchar
if not self.posix:
self.token = nextchar
self.state = nextchar
elif self.whitespace_split:
self.token = nextchar
self.state = 'a'
else:
self.token = nextchar
if self.token:
if self.token or (self.posix and quoted):
break # emit current token
else:
continue
elif self.state in self.quotes:
self.token = self.token + nextchar
if nextchar == self.state:
self.state = ' '
break
elif not nextchar: # end of file
quoted = 1
if not nextchar: # end of file
if self.debug >= 2:
print "shlex: I see EOF in quotes state"
# XXX what error should be raised here?
raise ValueError, "No closing quotation"
if nextchar == self.state:
if not self.posix:
self.token = self.token + nextchar
self.state = ' '
break
else:
self.state = 'a'
elif self.posix and nextchar in self.escape and \
self.state in self.escapedquotes:
escapedstate = self.state
self.state = nextchar
else:
self.token = self.token + nextchar
elif self.state in self.escape:
if not nextchar: # end of file
if self.debug >= 2:
print "shlex: I see EOF in escape state"
# XXX what error should be raised here?
raise ValueError, "No escaped character"
# In posix shells, only the quote itself or the escape
# character may be escaped within quotes.
if escapedstate in self.quotes and \
nextchar != self.state and nextchar != escapedstate:
self.token = self.token + self.state
self.token = self.token + nextchar
self.state = escapedstate
elif self.state == 'a':
if not nextchar:
self.state = None # end of file
@ -150,14 +207,26 @@ class shlex:
if self.debug >= 2:
print "shlex: I see whitespace in word state"
self.state = ' '
if self.token:
if self.token or (self.posix and quoted):
break # emit current token
else:
continue
elif nextchar in self.commenters:
self.instream.readline()
self.lineno = self.lineno + 1
elif nextchar in self.wordchars or nextchar in self.quotes:
if self.posix:
self.state = ' '
if self.token or (self.posix and quoted):
break # emit current token
else:
continue
elif self.posix and nextchar in self.quotes:
self.state = nextchar
elif self.posix and nextchar in self.escape:
escapedstate = 'a'
self.state = nextchar
elif nextchar in self.wordchars or nextchar in self.quotes \
or self.whitespace_split:
self.token = self.token + nextchar
else:
self.pushback = [nextchar] + self.pushback
@ -170,6 +239,8 @@ class shlex:
continue
result = self.token
self.token = ''
if self.posix and not quoted and result == '':
result = None
if self.debug > 1:
if result:
print "shlex: raw token=" + `result`
@ -182,7 +253,7 @@ class shlex:
if newfile[0] == '"':
newfile = newfile[1:-1]
# This implements cpp-like semantics for relative-path inclusion.
if type(self.infile) == type("") and not os.path.isabs(newfile):
if type(self.infile) in StringTypes and not os.path.isabs(newfile):
newfile = os.path.join(os.path.dirname(self.infile), newfile)
return (newfile, open(newfile, "r"))
@ -194,6 +265,19 @@ class shlex:
lineno = self.lineno
return "\"%s\", line %d: " % (infile, lineno)
def __iter__(self):
return self
def next(self):
token = self.get_token()
if token == self.eof:
raise StopIteration
return token
def split(s, posix=1, spaces=1):
lex = shlex(s, posix=posix)
lex.whitespace_split = spaces
return list(lex)
if __name__ == '__main__':
if len(sys.argv) == 1: