ref: 2aec1f8a09ae0bc9fb269d84ef53defebc47eede
dir: /sys/src/cmd/python/Demo/scripts/update.py/
#! /usr/bin/env python
# Update a bunch of files according to a script.
# The input file contains lines of the form <filename>:<lineno>:<text>,
# meaning that the given line of the given file is to be replaced
# by the given text. This is useful for performing global substitutions
# on grep output:
import os
import sys
import re
pat = '^([^: \t\n]+):([1-9][0-9]*):'
prog = re.compile(pat)
class FileObj:
def __init__(self, filename):
self.filename = filename
self.changed = 0
try:
self.lines = open(filename, 'r').readlines()
except IOError, msg:
print '*** Can\'t open "%s":' % filename, msg
self.lines = None
return
print 'diffing', self.filename
def finish(self):
if not self.changed:
print 'no changes to', self.filename
return
try:
os.rename(self.filename, self.filename + '~')
fp = open(self.filename, 'w')
except (os.error, IOError), msg:
print '*** Can\'t rewrite "%s":' % self.filename, msg
return
print 'writing', self.filename
for line in self.lines:
fp.write(line)
fp.close()
self.changed = 0
def process(self, lineno, rest):
if self.lines is None:
print '(not processed): %s:%s:%s' % (
self.filename, lineno, rest),
return
i = eval(lineno) - 1
if not 0 <= i < len(self.lines):
print '*** Line number out of range: %s:%s:%s' % (
self.filename, lineno, rest),
return
if self.lines[i] == rest:
print '(no change): %s:%s:%s' % (
self.filename, lineno, rest),
return
if not self.changed:
self.changed = 1
print '%sc%s' % (lineno, lineno)
print '<', self.lines[i],
print '---'
self.lines[i] = rest
print '>', self.lines[i],
def main():
if sys.argv[1:]:
try:
fp = open(sys.argv[1], 'r')
except IOError, msg:
print 'Can\'t open "%s":' % sys.argv[1], msg
sys.exit(1)
else:
fp = sys.stdin
curfile = None
while 1:
line = fp.readline()
if not line:
if curfile: curfile.finish()
break
n = prog.match(line)
if n < 0:
print 'Funny line:', line,
continue
filename, lineno = prog.group(1, 2)
if not curfile or filename <> curfile.filename:
if curfile: curfile.finish()
curfile = FileObj(filename)
curfile.process(lineno, line[n:])
if __name__ == "__main__":
main()