[Haskell-cafe] Re: how do you debug programs?

Chris Kuklewicz haskell at list.mightyreason.com
Wed Sep 6 16:23:19 EDT 2006

David Roundy wrote:
> On Wed, Sep 06, 2006 at 09:56:17AM -0700, Jason Dagit wrote:
>> Or maybe even more extreme you could use template haskell or the c
>> preprocessor to fill in the line number + column.
> Which is precisely what darcs does for fromJust (which we use a lot):
> we define a C preprocessor macro fromJust.  It's ugly, but beats any
> other choice I'm aware of.  I wish that built in functions that call
> error could be automatically this way...

This old mailing list message may help: 

> Suggested by a question from sethk on #haskell irc channel. 
> Solves an FAQ where people have often resorted to cpp or m4:
> a `trace' that prints line numbers.    


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