| Issue 222: | empty has no effect with file arguments | |
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What steps will reproduce the problem? 1. cabal install cmdargs 2. run an example from http://community.haskell.org/~ndm/cmdargs/ without arguments > $ cat cmdargs.hs > {-# LANGUAGE DeriveDataTypeable #-} > import System.Console.CmdArgs > data Sample = Sample {hello :: String} deriving (Show, Data, Typeable) > sample = mode $ Sample{hello = def &= text "World argument" & empty "world"} > main = print =<< cmdArgs "Sample v1, (C) Neil Mitchell 2009" [sample] > $ runhaskell cmdargs.hs --hello=Neil > Sample {hello = "Neil"} > $ runhaskell cmdargs.hs > Sample {hello = ""} What is the expected output? What do you see instead? I expected that default value supplied with `empty' to be used to construct a `Sample'. Something like this: > Sample {hello = "world"} What version of the product are you using? On what operating system? (Saying "latest" is fine, especially for Hoogle web search) Debian Linux (lenny) i386, GHC 6.10.3, cmdargs-0.1 |
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,
Oct 11, 2009
I believe doing:
> sample = mode $ Sample{hello = "world" &= text "World argument"}
Should work fine. If empty is being ignored I guess I should either use it, or give an
error message saying it's being ignored. I'll have a think.
Summary: empty has no effect with file arguments
Status: Accepted Labels: Proj-CmdArgs |
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,
Oct 22, 2009
The workaround, which you suggested, works. Thank you. |
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,
Oct 30, 2009
This had me confused as well. Especially when considering the description of `empty`. |
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