Weird behavior with getopt for invalid user input
Andrew Pennebaker
andrew.pennebaker at gmail.com
Sat Dec 8 19:48:24 UTC 2018
In many getopt implementations, the -h/--help banner is printed
when the user supplies invalid arguments. However, D's getopt
instead throws an exception, printing a stack trace and confusing
some non-technical users.
That's okay, we can catch GetoptException and try to print the
usage information instead. But that also doesn't work so well, as
the getopt spec cannot bind to a variable when an exception is
thrown. Again, other getopt implementations tend to separate the
getopt spec object construction from argument validation into
separate function calls, which gives the programmer more
flexibility for how to handle any errors.
Sigh, when I manually `defaultGetoptPrinter(format("Usage: %s
[OPTIONS]", program), opts.options);`, I think I can do this by
typing out the getopt spec a second time, overriding the args
with ["-h"]. But this is starting to require a ridiculous number
of hacks, when getopt could have just executed -h on error, as
many users would expect.
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