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144 lines
4.8 KiB
Python
Executable file
144 lines
4.8 KiB
Python
Executable file
#!/usr/bin/env python
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# -*- Mode: Python; py-indent-offset: 4 -*-
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from __future__ import generators
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import string
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from cStringIO import StringIO
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class error(Exception):
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def __init__(self, filename, lineno, msg):
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Exception.__init__(self, msg)
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self.filename = filename
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self.lineno = lineno
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self.msg = msg
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def __str__(self):
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return '%s:%d: error: %s' % (self.filename, self.lineno, self.msg)
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trans = [' '] * 256
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for i in range(256):
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if chr(i) in string.letters + string.digits + '_':
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trans[i] = chr(i)
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else:
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trans[i] = '_'
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trans = string.join(trans, '')
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def parse(filename):
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if isinstance(filename, str):
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fp = open(filename, 'r')
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else: # if not string, assume it is some kind of iterator
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fp = filename
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filename = getattr(fp, 'name', '<unknown>')
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whitespace = ' \t\n\r\x0b\x0c'
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nonsymbol = whitespace + '();\'"'
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stack = []
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openlines = []
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lineno = 0
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for line in fp:
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pos = 0
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lineno += 1
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while pos < len(line):
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if line[pos] in whitespace: # ignore whitespace
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pass
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elif line[pos] == ';': # comment
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break
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elif line[pos:pos+2] == "'(":
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pass # the open parenthesis will be handled next iteration
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elif line[pos] == '(':
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stack.append(())
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openlines.append(lineno)
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elif line[pos] == ')':
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if len(stack) == 0:
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raise error(filename, lineno, 'close parenthesis found when none open')
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closed = stack[-1]
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del stack[-1]
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del openlines[-1]
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if stack:
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stack[-1] += (closed,)
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else:
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yield closed
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elif line[pos] == '"': # quoted string
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if not stack:
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raise error(filename, lineno,
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'string found outside of s-expression')
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endpos = pos + 1
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chars = []
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while endpos < len(line):
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if endpos+1 < len(line) and line[endpos] == '\\':
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endpos += 1
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if line[endpos] == 'n':
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chars.append('\n')
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elif line[endpos] == 'r':
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chars.append('\r')
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elif line[endpos] == 't':
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chars.append('\t')
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else:
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chars.append('\\')
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chars.append(line[endpos])
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elif line[endpos] == '"':
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break
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else:
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chars.append(line[endpos])
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endpos += 1
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if endpos >= len(line):
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raise error(filename, lineno, "unclosed quoted string")
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pos = endpos
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stack[-1] += (''.join(chars),)
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else: # symbol/number
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if not stack:
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raise error(filename, lineno,
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'identifier found outside of s-expression')
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endpos = pos
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while endpos < len(line) and line[endpos] not in nonsymbol:
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endpos += 1
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symbol = line[pos:endpos]
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pos = max(pos, endpos-1)
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try: symbol = int(symbol)
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except ValueError:
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try: symbol = float(symbol)
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except ValueError: pass
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stack[-1] += (symbol,)
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pos += 1
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if len(stack) != 0:
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msg = '%d unclosed parentheses found at end of ' \
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'file (opened on line(s) %s)' % (len(stack),
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', '.join(map(str, openlines)))
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raise error(filename, lineno, msg)
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class Parser:
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def __init__(self, filename):
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"""Argument is either a string, a parse tree, or file object"""
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self.filename = filename
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def startParsing(self, filename=None):
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statements = parse(filename or self.filename)
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for statement in statements:
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self.handle(statement)
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def handle(self, tup):
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cmd = string.translate(tup[0], trans)
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if hasattr(self, cmd):
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getattr(self, cmd)(*tup[1:])
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else:
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self.unknown(tup)
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def unknown(self, tup):
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pass
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_testString = """; a scheme file
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(define-func gdk_font_load ; a comment at end of line
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GdkFont
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((string name)))
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(define-boxed GdkEvent
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gdk_event_copy
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gdk_event_free
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"sizeof(GdkEvent)")
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"""
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if __name__ == '__main__':
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import sys
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if sys.argv[1:]:
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fp = open(sys.argv[1])
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else:
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fp = StringIO(_testString)
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statements = parse(fp)
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for s in statements:
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print `s`
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