Spencer Janssen writes:

Please do not use the PLEAC Haskell cookbook for learning Haskell. The author redefined many of the standard operators to produce code that isn't standard Haskell.

Here are some choice snippets from the first chapter:

Now, we all know that the (.) operator is function composition, right? Not in this example! The author has silently defined "(.) = flip ($)" -- a sort of reverse function application.

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cut2fmt xs = xs.foldl aux (1,[]).snd.(GrabAll:).reverse

Ah yes, (^) is surely exponent here? Nope, it's some kind of unholy combination of show and (++).

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s9 = "I have "^10+1^" guanacos."

More of the same:

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piece = s!![-8 .. -5]

Complaining aside, I do agree with you: we need more example-style documentation. Rewriting the PLEAC cookbook might be a good start.

i agree. A friend of mine did this haskell PLEAC version, and i would really like to have a /standard/ haskell one. (alas i've no more time to do it myself...)

On 14/11/06, chris moline wrote:

--- brad clawsie wrote:

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it would be great if some of the more informed posters here took a stab at filling in

http://pleac.sourceforge.net/pleac_haskell/index.html

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a neat site for cookbook-style problem solving

What I've always found funny about pleac is that none of the examples are actually Haskell, but some weird Haskell-with-oo-features. Does anyone know what language it is?

Here are some examples:

password = [1..8].mapM (\_ -> rand (0, chars.length -1) >>> (chars!))

-- in haskell, regexp are first class, then can be appended, sometimes easier to read m0' s = .... (s ==~ dec_number) ....

They are actually Haskell, but notice the appendix: http://pleac.sourceforge.net/pleac_haskell/a1102.html It's Haskell with a completely bizarre prelude. No real new features were added to the language itself. Replacing composition with reverse function application is a waste of operator symbols. Personally, if I was going to change (.), it would be to define it as fmap, which (as a number of people, myself included, have pointed out) together with the instance of Functor for ((->) e) would generalise ordinary composition, map, liftM, etc. - Cale