[Haskell-cafe] handling non-string command line arguments

Johan Larson johan.g.larson at gmail.com
Sat Jun 28 19:28:15 UTC 2014

I've been looking at choices for parsing command line arguments, including
getOpt. The examples I can find focus on string arguments, whereas I am
interested in numbers. In the application at hand, it is particularly
important to issue clear error messages when arguments don't parse as
numbers or are out of range.

I could use getOpt as a first pass with string arguments and then turn the
strings into validated numbers in a second pass, but that's a bit awkward.
Alternately I could use the options records with Options -> IO Options
functions. But both of these solutions treat type mismatches differently
from other options errors.

Has anyone found a cleaner solution?

Johan Larson -- Toronto, Canada
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