[Haskell-cafe] "doctest" for haskell -- a good project?

Shaun Cutts shaun at cuttshome.net
Sat Mar 22 14:02:16 EDT 2008

> >  resemble a formal specification.  For a couple of 
> examples, see my  
> > RangedSet package and Neil Mitchel's FilePath package.  I manually  
> > copied the RangedSet tests into the Haddock documentation, 
> while Neil  
> > wrote a small Haskell script to extract his tests from his 
> > documentation  automatically.  Unfortunately his script is tied to 
> > specific aspects of  his FilePath package.
> Yes, the problem was that FilePath wants to execute half the 
> tests twice with different modules, and half with just one 
> namespace. As far as tests go, this is a very wacky 
> requirement. I wanted to generalise it into a tool, but 
> couldn't find a sensible generalisation that still worked 
> with filepath - and hence didn't bother. I think the solution 
> is to not permit the quirkyness of filepath, and write a 
> general solution for everything else.

Niel -- I understand your script is part of FilePath... might it be a good
starting point for abstraction? Can you point me to it?

> As someone who has frequently considered writing this, even 
> going as far as brainstorming on a whiteboard, I would be an 
> enthusiastic user of this. I think the lack of this tool in 
> Haskell is a big hole which someone needs to fill. I 
> particularly like the facility in FilePath:
> -- > x == reverse (reverse x)
> -- > reverse "neil" = "lien"
> i.e. I can write both quickcheck properties (quantified over 
> all single letter variables), or I can write an instance 
> (like doctest in
> Python)
> Thanks, and good luck!
> Neil
Thank you for the support... This might take me a while, I must warn, as
this is an "after work" project, and I am a consultant, so "after work"
often doesn't come :). But its certainly motivating to work on something
right away that could be useful (to myself as well).

- Shaun

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