1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
|
"""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.
import os.path
import sys
class shlex:
"A lexical analyzer class for simple shell-like syntaxes."
def __init__(self, instream=None, infile=None):
if instream:
self.instream = instream
self.infile = infile
else:
self.instream = sys.stdin
self.infile = None
self.commenters = '#'
self.wordchars = ('abcdfeghijklmnopqrstuvwxyz'
'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_')
self.whitespace = ' \t\r\n'
self.quotes = '\'"'
self.state = ' '
self.pushback = []
self.lineno = 1
self.debug = 0
self.token = ''
self.filestack = []
self.source = None
if self.debug:
print 'shlex: reading from %s, line %d' \
% (self.instream, self.lineno)
def push_token(self, tok):
"Push a token onto the stack popped by the get_token method"
if self.debug >= 1:
print "shlex: pushing token " + `tok`
self.pushback = [tok] + self.pushback
def push_source(self, newstream, newfile=None):
"Push an input source onto the lexer's input source stack."
self.filestack.insert(0, (self.infile, self.instream, self.lineno))
self.infile = newfile
self.instream = newstream
self.lineno = 1
if self.debug:
if newfile:
print 'shlex: pushing to file %s' % (self.infile,)
else:
print 'shlex: pushing to stream %s' % (self.instream,)
def pop_source(self):
"Pop the input source stack."
self.instream.close()
(self.infile, self.instream, self.lineno) = self.filestack[0]
self.filestack = self.filestack[1:]
if self.debug:
print 'shlex: popping to %s, line %d' \
% (self.instream, self.lineno)
self.state = ' '
def get_token(self):
"Get a token from the input stream (or from stack if it's nonempty)"
if self.pushback:
tok = self.pushback[0]
self.pushback = self.pushback[1:]
if self.debug >= 1:
print "shlex: popping token " + `tok`
return tok
# 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()
# Maybe we got EOF instead?
while raw == "":
if len(self.filestack) == 0:
return ""
else:
self.pop_source()
raw = self.get_token()
# Neither inclusion nor EOF
if self.debug >= 1:
if raw:
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)"
tok = ''
while 1:
nextchar = self.instream.read(1)
if nextchar == '\n':
self.lineno = self.lineno + 1
if self.debug >= 3:
print "shlex: in state", repr(self.state), \
"I see character:", repr(nextchar)
if self.state is None:
self.token = '' # past end of file
break
elif self.state == ' ':
if not nextchar:
self.state = None # end of file
break
elif nextchar in self.whitespace:
if self.debug >= 2:
print "shlex: I see whitespace in whitespace state"
if self.token:
break # emit current token
else:
continue
elif nextchar in self.commenters:
self.instream.readline()
self.lineno = self.lineno + 1
elif nextchar in self.wordchars:
self.token = nextchar
self.state = 'a'
elif nextchar in self.quotes:
self.token = nextchar
self.state = nextchar
else:
self.token = nextchar
if self.token:
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
if self.debug >= 2:
print "shlex: I see EOF in quotes state"
# XXX what error should be raised here?
raise ValueError, "No closing quotation"
elif self.state == 'a':
if not nextchar:
self.state = None # end of file
break
elif nextchar in self.whitespace:
if self.debug >= 2:
print "shlex: I see whitespace in word state"
self.state = ' '
if self.token:
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:
self.token = self.token + nextchar
else:
self.pushback = [nextchar] + self.pushback
if self.debug >= 2:
print "shlex: I see punctuation in word state"
self.state = ' '
if self.token:
break # emit current token
else:
continue
result = self.token
self.token = ''
if self.debug > 1:
if result:
print "shlex: raw token=" + `result`
else:
print "shlex: raw token=EOF"
return result
def sourcehook(self, newfile):
"Hook called on a filename to be sourced."
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):
newfile = os.path.join(os.path.dirname(self.infile), newfile)
return (newfile, open(newfile, "r"))
def error_leader(self, infile=None, lineno=None):
"Emit a C-compiler-like, Emacs-friendly error-message leader."
if not infile:
infile = self.infile
if not lineno:
lineno = self.lineno
return "\"%s\", line %d: " % (infile, lineno)
if __name__ == '__main__':
if len(sys.argv) == 1:
lexer = shlex()
else:
file = sys.argv[1]
lexer = shlex(open(file), file)
while 1:
tt = lexer.get_token()
if tt:
print "Token: " + repr(tt)
else:
break
|
