A quick example of using readProcess in Haskell to "shell out" an integer factorization task, calling the Linux "factor" command (extracted from the Prime Day calculator):
import System.Process; factor :: Integer -> IO([](Integer)); factor x = ((readProcess "factor" [(show x)] "") >>= (return . tail . (map read) . words));
A better way might use the Pari library.
2 comments :
What happened to the type signature?
factor :: Integer -> IO([](Integer));
should obviously be
factor :: Integer -> IO [Integer]
It may be funny-looking, but it does parse!
I use a (unpublished) preprocessor that emits types in "prefix" form, even for the list type constructor [].
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