Re: [Haskell-cafe] some way to reverse engineer lambda expressionsout of the debugger?

works like a charm :) 2007/1/11, Claus Reinke :

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Looks very nice!

thanks!-)

it is far from a full-blown solution to the question in the subject, but it has its uses.

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However, I'm doing my learning on ghci and got an error when I tried to load it.

Is this hugs only, or should I try harder?

I was using Hugs when I wrote that, but it works in GHC almost as well. the error message really ought to point to the option needed, which is -fglasgow-exts

if you don't want to set the options by hand, just add the following pragma to the top of R.hs:

{-# OPTIONS_GHC -fglasgow-exts #-}

more annoying is that ghci will ignore the default directive, so you'll need to give explicit types when you want representations:

*Main> foldr (+) 0 [1..4] 10 *Main> foldr (+) 0 [1..4] :: R Int (1 + (2 + (3 + (4 + 0)))) *Main> map (*) [1,2]

<interactive>:1:0: No instance for (Show (t -> t)) arising from use of `print' at <interactive>:1:0-12 Possible fix: add an instance declaration for (Show (t -> t)) In the call (print it) In the expression: print it In a 'do' expression: print it *Main> map (*) [1,2] :: [R Int -> R Int] [\x->(1 * x),\x->(2 * x)]

claus

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2007/1/11, Malcolm Wallace :

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Bulat Ziganshin wrote:

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tphyahoo wrote:

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*UnixTools> explodeLambda( map (*) [1,2] ) [(\x ->> 1*x),(\x -> 2*x)]

Have a play with this, from Claus Reinke: http://www.cs.kent.ac.uk/people/staff/cr3/toolbox/haskell/R.hs

Regards, Malcolm _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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