!optparse --- Parser for command line options — Callback example 2: check option order
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Here's a slightly more interesting example: record the fact that -a is seen, but blow up if it comes after -b in the command-line.
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Here's a slightly more interesting example: record the fact that -a is seen, but blow up if it comes after -b in the command-line.
def check_order(option, opt_str, value, parser): if parser.values.b: raise OptionValueError("can't use -a after -b") parser.values.a = 1 ... parser.add_option("-a", action="callback", callback=check_order) parser.add_option("-b", action="store_true", dest="b")
Attribution: Adapted from Python Documentation under PSF-2.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, removed long code blocks, and shortened it for retrieval. Verify version-sensitive details at the source.
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Python Documentation — Doc/library/optparse.rst :: Callback example 2: check option order ↗Revision 948fd7e5c084 · PSF-2.0