[Haskell-cafe] Prelude.head: empty list

[Han Joosten]

Thanks all! Plenty good options, fortunately I found my bug pretty fast by
simple code inspection :))

2016-03-12 4:28 GMT+01:00 Chris Wong <lambda.fairy at gmail.com>:

> On Sat, Mar 12, 2016 at 8:07 AM, Jonas Scholl
> <anselm.scholl at tu-harburg.de> wrote:
> > You mean like this?
> >
> >   default-extensions:  CPP
> >   cpp-options:
> >
> -Dhead=(foldr(const)(error("head:\x20\x65mpty\x20list\x20in\x20"++__FILE__++":"++show(__LINE__))).(take$1))
>
> That's pretty cool!
>
> By the way: can the (take$1) be removed? foldr should be lazy enough
> already.
>
> --
> Chris Wong (https://lambda.xyz)
>
> "I had not the vaguest idea what this meant and when I could not
> remember the words, my tutor threw the book at my head, which did not
> stimulate my intellect in any way." -- Bertrand Russell
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