507 lines
17 KiB
Python
Executable File
507 lines
17 KiB
Python
Executable File
#! /usr/bin/env python3
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# This file contains a class and a main program that perform three
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# related (though complimentary) formatting operations on Python
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# programs. When called as "pindent -c", it takes a valid Python
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# program as input and outputs a version augmented with block-closing
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# comments. When called as "pindent -d", it assumes its input is a
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# Python program with block-closing comments and outputs a commentless
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# version. When called as "pindent -r" it assumes its input is a
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# Python program with block-closing comments but with its indentation
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# messed up, and outputs a properly indented version.
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# A "block-closing comment" is a comment of the form '# end <keyword>'
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# where <keyword> is the keyword that opened the block. If the
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# opening keyword is 'def' or 'class', the function or class name may
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# be repeated in the block-closing comment as well. Here is an
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# example of a program fully augmented with block-closing comments:
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# def foobar(a, b):
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# if a == b:
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# a = a+1
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# elif a < b:
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# b = b-1
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# if b > a: a = a-1
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# # end if
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# else:
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# print 'oops!'
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# # end if
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# # end def foobar
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# Note that only the last part of an if...elif...else... block needs a
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# block-closing comment; the same is true for other compound
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# statements (e.g. try...except). Also note that "short-form" blocks
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# like the second 'if' in the example must be closed as well;
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# otherwise the 'else' in the example would be ambiguous (remember
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# that indentation is not significant when interpreting block-closing
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# comments).
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# The operations are idempotent (i.e. applied to their own output
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# they yield an identical result). Running first "pindent -c" and
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# then "pindent -r" on a valid Python program produces a program that
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# is semantically identical to the input (though its indentation may
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# be different). Running "pindent -e" on that output produces a
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# program that only differs from the original in indentation.
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# Other options:
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# -s stepsize: set the indentation step size (default 8)
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# -t tabsize : set the number of spaces a tab character is worth (default 8)
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# -e : expand TABs into spaces
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# file ... : input file(s) (default standard input)
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# The results always go to standard output
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# Caveats:
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# - comments ending in a backslash will be mistaken for continued lines
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# - continuations using backslash are always left unchanged
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# - continuations inside parentheses are not extra indented by -r
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# but must be indented for -c to work correctly (this breaks
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# idempotency!)
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# - continued lines inside triple-quoted strings are totally garbled
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# Secret feature:
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# - On input, a block may also be closed with an "end statement" --
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# this is a block-closing comment without the '#' sign.
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# Possible improvements:
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# - check syntax based on transitions in 'next' table
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# - better error reporting
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# - better error recovery
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# - check identifier after class/def
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# The following wishes need a more complete tokenization of the source:
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# - Don't get fooled by comments ending in backslash
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# - reindent continuation lines indicated by backslash
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# - handle continuation lines inside parentheses/braces/brackets
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# - handle triple quoted strings spanning lines
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# - realign comments
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# - optionally do much more thorough reformatting, a la C indent
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# Defaults
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STEPSIZE = 8
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TABSIZE = 8
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EXPANDTABS = False
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import io
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import re
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import sys
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next = {}
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next['if'] = next['elif'] = 'elif', 'else', 'end'
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next['while'] = next['for'] = 'else', 'end'
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next['try'] = 'except', 'finally'
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next['except'] = 'except', 'else', 'finally', 'end'
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next['else'] = next['finally'] = next['with'] = \
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next['def'] = next['class'] = 'end'
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next['end'] = ()
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start = 'if', 'while', 'for', 'try', 'with', 'def', 'class'
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class PythonIndenter:
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def __init__(self, fpi = sys.stdin, fpo = sys.stdout,
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indentsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS):
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self.fpi = fpi
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self.fpo = fpo
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self.indentsize = indentsize
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self.tabsize = tabsize
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self.lineno = 0
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self.expandtabs = expandtabs
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self._write = fpo.write
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self.kwprog = re.compile(
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r'^(?:\s|\\\n)*(?P<kw>[a-z]+)'
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r'((?:\s|\\\n)+(?P<id>[a-zA-Z_]\w*))?'
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r'[^\w]')
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self.endprog = re.compile(
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r'^(?:\s|\\\n)*#?\s*end\s+(?P<kw>[a-z]+)'
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r'(\s+(?P<id>[a-zA-Z_]\w*))?'
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r'[^\w]')
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self.wsprog = re.compile(r'^[ \t]*')
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# end def __init__
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def write(self, line):
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if self.expandtabs:
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self._write(line.expandtabs(self.tabsize))
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else:
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self._write(line)
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# end if
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# end def write
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def readline(self):
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line = self.fpi.readline()
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if line: self.lineno += 1
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# end if
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return line
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# end def readline
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def error(self, fmt, *args):
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if args: fmt = fmt % args
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# end if
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sys.stderr.write('Error at line %d: %s\n' % (self.lineno, fmt))
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self.write('### %s ###\n' % fmt)
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# end def error
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def getline(self):
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line = self.readline()
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while line[-2:] == '\\\n':
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line2 = self.readline()
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if not line2: break
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# end if
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line += line2
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# end while
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return line
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# end def getline
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def putline(self, line, indent):
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tabs, spaces = divmod(indent*self.indentsize, self.tabsize)
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i = self.wsprog.match(line).end()
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line = line[i:]
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if line[:1] not in ('\n', '\r', ''):
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line = '\t'*tabs + ' '*spaces + line
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# end if
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self.write(line)
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# end def putline
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def reformat(self):
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stack = []
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while True:
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line = self.getline()
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if not line: break # EOF
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# end if
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m = self.endprog.match(line)
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if m:
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kw = 'end'
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kw2 = m.group('kw')
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if not stack:
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self.error('unexpected end')
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elif stack.pop()[0] != kw2:
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self.error('unmatched end')
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# end if
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self.putline(line, len(stack))
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continue
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# end if
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m = self.kwprog.match(line)
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if m:
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kw = m.group('kw')
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if kw in start:
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self.putline(line, len(stack))
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stack.append((kw, kw))
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continue
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# end if
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if kw in next and stack:
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self.putline(line, len(stack)-1)
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kwa, kwb = stack[-1]
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stack[-1] = kwa, kw
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continue
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# end if
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# end if
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self.putline(line, len(stack))
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# end while
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if stack:
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self.error('unterminated keywords')
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for kwa, kwb in stack:
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self.write('\t%s\n' % kwa)
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# end for
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# end if
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# end def reformat
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def delete(self):
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begin_counter = 0
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end_counter = 0
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while True:
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line = self.getline()
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if not line: break # EOF
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# end if
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m = self.endprog.match(line)
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if m:
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end_counter += 1
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continue
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# end if
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m = self.kwprog.match(line)
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if m:
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kw = m.group('kw')
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if kw in start:
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begin_counter += 1
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# end if
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# end if
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self.write(line)
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# end while
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if begin_counter - end_counter < 0:
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sys.stderr.write('Warning: input contained more end tags than expected\n')
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elif begin_counter - end_counter > 0:
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sys.stderr.write('Warning: input contained less end tags than expected\n')
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# end if
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# end def delete
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def complete(self):
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stack = []
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todo = []
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currentws = thisid = firstkw = lastkw = topid = ''
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while True:
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line = self.getline()
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i = self.wsprog.match(line).end()
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m = self.endprog.match(line)
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if m:
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thiskw = 'end'
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endkw = m.group('kw')
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thisid = m.group('id')
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else:
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m = self.kwprog.match(line)
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if m:
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thiskw = m.group('kw')
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if thiskw not in next:
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thiskw = ''
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# end if
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if thiskw in ('def', 'class'):
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thisid = m.group('id')
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else:
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thisid = ''
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# end if
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elif line[i:i+1] in ('\n', '#'):
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todo.append(line)
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continue
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else:
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thiskw = ''
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# end if
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# end if
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indentws = line[:i]
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indent = len(indentws.expandtabs(self.tabsize))
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current = len(currentws.expandtabs(self.tabsize))
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while indent < current:
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if firstkw:
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if topid:
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s = '# end %s %s\n' % (
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firstkw, topid)
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else:
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s = '# end %s\n' % firstkw
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# end if
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self.write(currentws + s)
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firstkw = lastkw = ''
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# end if
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currentws, firstkw, lastkw, topid = stack.pop()
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current = len(currentws.expandtabs(self.tabsize))
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# end while
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if indent == current and firstkw:
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if thiskw == 'end':
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if endkw != firstkw:
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self.error('mismatched end')
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# end if
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firstkw = lastkw = ''
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elif not thiskw or thiskw in start:
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if topid:
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s = '# end %s %s\n' % (
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firstkw, topid)
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else:
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s = '# end %s\n' % firstkw
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# end if
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self.write(currentws + s)
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firstkw = lastkw = topid = ''
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# end if
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# end if
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if indent > current:
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stack.append((currentws, firstkw, lastkw, topid))
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if thiskw and thiskw not in start:
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# error
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thiskw = ''
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# end if
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currentws, firstkw, lastkw, topid = \
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indentws, thiskw, thiskw, thisid
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# end if
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if thiskw:
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if thiskw in start:
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firstkw = lastkw = thiskw
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topid = thisid
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else:
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lastkw = thiskw
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# end if
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# end if
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for l in todo: self.write(l)
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# end for
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todo = []
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if not line: break
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# end if
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self.write(line)
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# end while
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# end def complete
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# end class PythonIndenter
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# Simplified user interface
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# - xxx_filter(input, output): read and write file objects
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# - xxx_string(s): take and return string object
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# - xxx_file(filename): process file in place, return true iff changed
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def complete_filter(input = sys.stdin, output = sys.stdout,
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stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS):
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pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs)
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pi.complete()
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# end def complete_filter
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def delete_filter(input= sys.stdin, output = sys.stdout,
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stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS):
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pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs)
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pi.delete()
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# end def delete_filter
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def reformat_filter(input = sys.stdin, output = sys.stdout,
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stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS):
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pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs)
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pi.reformat()
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# end def reformat_filter
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def complete_string(source, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS):
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input = io.StringIO(source)
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output = io.StringIO()
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pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs)
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pi.complete()
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return output.getvalue()
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# end def complete_string
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def delete_string(source, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS):
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input = io.StringIO(source)
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output = io.StringIO()
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pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs)
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pi.delete()
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return output.getvalue()
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# end def delete_string
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def reformat_string(source, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS):
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input = io.StringIO(source)
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output = io.StringIO()
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pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs)
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pi.reformat()
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return output.getvalue()
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# end def reformat_string
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def make_backup(filename):
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import os, os.path
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backup = filename + '~'
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if os.path.lexists(backup):
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try:
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os.remove(backup)
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except OSError:
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print("Can't remove backup %r" % (backup,), file=sys.stderr)
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# end try
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# end if
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try:
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os.rename(filename, backup)
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except OSError:
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print("Can't rename %r to %r" % (filename, backup), file=sys.stderr)
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# end try
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# end def make_backup
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def complete_file(filename, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS):
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with open(filename, 'r') as f:
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source = f.read()
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# end with
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result = complete_string(source, stepsize, tabsize, expandtabs)
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if source == result: return 0
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# end if
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make_backup(filename)
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with open(filename, 'w') as f:
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f.write(result)
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# end with
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return 1
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# end def complete_file
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def delete_file(filename, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS):
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with open(filename, 'r') as f:
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source = f.read()
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# end with
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result = delete_string(source, stepsize, tabsize, expandtabs)
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if source == result: return 0
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# end if
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make_backup(filename)
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with open(filename, 'w') as f:
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f.write(result)
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# end with
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return 1
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# end def delete_file
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def reformat_file(filename, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS):
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with open(filename, 'r') as f:
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source = f.read()
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# end with
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result = reformat_string(source, stepsize, tabsize, expandtabs)
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if source == result: return 0
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# end if
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make_backup(filename)
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with open(filename, 'w') as f:
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f.write(result)
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# end with
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return 1
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# end def reformat_file
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# Test program when called as a script
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usage = """
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usage: pindent (-c|-d|-r) [-s stepsize] [-t tabsize] [-e] [file] ...
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-c : complete a correctly indented program (add #end directives)
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-d : delete #end directives
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-r : reformat a completed program (use #end directives)
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-s stepsize: indentation step (default %(STEPSIZE)d)
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-t tabsize : the worth in spaces of a tab (default %(TABSIZE)d)
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-e : expand TABs into spaces (default OFF)
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[file] ... : files are changed in place, with backups in file~
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If no files are specified or a single - is given,
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the program acts as a filter (reads stdin, writes stdout).
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""" % vars()
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def error_both(op1, op2):
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sys.stderr.write('Error: You can not specify both '+op1+' and -'+op2[0]+' at the same time\n')
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sys.stderr.write(usage)
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sys.exit(2)
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# end def error_both
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def test():
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import getopt
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try:
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opts, args = getopt.getopt(sys.argv[1:], 'cdrs:t:e')
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except getopt.error as msg:
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sys.stderr.write('Error: %s\n' % msg)
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sys.stderr.write(usage)
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sys.exit(2)
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# end try
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action = None
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stepsize = STEPSIZE
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tabsize = TABSIZE
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expandtabs = EXPANDTABS
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for o, a in opts:
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if o == '-c':
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if action: error_both(o, action)
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# end if
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action = 'complete'
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elif o == '-d':
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if action: error_both(o, action)
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# end if
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action = 'delete'
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elif o == '-r':
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if action: error_both(o, action)
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# end if
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action = 'reformat'
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elif o == '-s':
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stepsize = int(a)
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elif o == '-t':
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tabsize = int(a)
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elif o == '-e':
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expandtabs = True
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# end if
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# end for
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if not action:
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sys.stderr.write(
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'You must specify -c(omplete), -d(elete) or -r(eformat)\n')
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sys.stderr.write(usage)
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sys.exit(2)
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# end if
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if not args or args == ['-']:
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action = eval(action + '_filter')
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action(sys.stdin, sys.stdout, stepsize, tabsize, expandtabs)
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else:
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action = eval(action + '_file')
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for filename in args:
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action(filename, stepsize, tabsize, expandtabs)
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# end for
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# end if
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# end def test
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if __name__ == '__main__':
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test()
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# end if
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