[Haskell-cafe] Re: Allowing hyphens in identifiers

[Richard O'Keefe]

On Dec 10, 2009, at 12:05 PM, Deniz Dogan wrote:

> 2009/12/9 Richard O'Keefe <ok at cs.otago.ac.nz>:
>>
>> Here is such a preprocessor.  This is meant for people to try out.
>> I don't claim that it's perfect, it's just a quick hack.
>>
>
> Is there any flag I can pass to e.g. GHC to make it use the
> preprocessor automagically or do I write my own little hack to apply
> the preprocessor?

It's amazing what you find in the manual:
	-F	
		runs a custom preprocessor.
		Let the source file be $S.
		First, literate Haskell processing is done,
		producing $L.
		Then <your program> "$S" "$L" "$O" is run,
		where $O is where GHC wants your program to
		write its output.
		GHC then reads $O.

	-pgmF cmd
		tells GHC to use cmd as the custom preprocessor.

My little hspp was written before I realised this could be done,
so I had to whip up
	#!/bin/sh
	exec hspp <"$2" >"$3"
and use that.
Sample session:

	m% cat main.hs
	main = print (take-while (<10) [1..])
	m% ghc -F -pgmF hspp.sh main.hs
	m% a.out
	[1,2,3,4,5,6,7,8,9]

If there isn't a GHC option to count the dragons in the moon,
there soon will be.

One option that would be nice would be accepting -help as well
as --help.