[Eric]
Right...one of which completely misses the point by suggesting that this is a filter framework,
True. It's a tad more general than just a filter. How about UnixishTextfileTransformFramework since that captures it's most distinguishing feature (the fact that it follows a popular unix convention). Also hints that it would chew the hell out of a binary file on Windows. [Guido]
- A framework like this should be structured as a class or set of related classes, not a bunch of functions with function arguments.
[Eric]
Yes, I thought of this. There's a reason I didn't do it that way. Method override would work just fine as a way to pass in the filename transformer, but not the data transformer.
The problem is this: the driver or "go do it" method of your hypothetical class (the one you'd pass sys.argv[1:]) can't know which overriden method to call in advance, because which one is right would depend on the argument signature of the hook function
Who cares about signatures? Try the attached. - Gordon -------------- Enclosure number 1 ---------------- import sys, os class UnixishFileTransformer: def transformFile(self, infp, outfp): raise NotImplementedError def transformData(self, data): raise NotImplementedError def transformLine(self, line): raise NotImplementedError def transformFilename(self, nm): raise NotImplementedError def run(self, args): if not args: self.fnm = "stdin" self._do_one(sys.stdin, sys.stdout) else: for fnm in args: if fnm == '-': infp = sys.stdin self.fnm = "stdin" else: infp = open(fnm, 'r') self.fnm = fnm tempfile = file + ".~%s-%d~" % (name, os.getpid()) outfp = open(tempfile, "w") try: self._do_one(infp, outfp) except: os.remove(tempfile) raise infp.close() outfp.close() try: newnm = self.transformFilename(self.fnm) except NotImplementedError: if filecmp.cmp(file, tempfile): continue newnm = self.fnm os.remove(self.fnm) os.rename(tempfile, newnm) def _do_one(self, infp, outfp): try: self.transformFile(infp, outfp) except NotImplementedError: try: while 1: line = infp.readline() if not line: break outfp.write(self.transformLine(line)) except NotImplementedError: try: lump = line + infp.read() outfp.write(self.transformData(lump)) except NotImplementedError: raise NotImplementedError, "no implementation of a transform method provided" if __name__ == '__main__': import getopt class T1(UnixishFileTransformer): def transformFilename(self, fnm): return fnm+'.out' def transformFile(self, infp, outfp): while 1: line = infp.readline() if not line: break if line == "\n": outfp.write("------------------------------------------\n") outfp.write(line) class T2(UnixishFileTransformer): def transformFilename(self, fnm): return fnm+'.out2' def transformLine(self, line): return "<" + line[:-1] + ">\n" class T3(UnixishFileTransformer): def transformFilename(self, fnm): return fnm+'.foo' def transformData(self, data): lines = data.split("\n") lines.reverse() return "\n".join(lines) (options, arguments) = getopt.getopt(sys.argv[1:], "fls") for (switch, val) in options: if switch == '-f': t = T1() t.run(arguments) elif switch == '-l': t = T2() t.run(arguments) elif switch == '-s': t = T3() t.run(arguments) else: print "Unknown option."