[Haskell-cafe] How can i safely change the value of specified key
?
minh thu
noteed at gmail.com
Thu Oct 22 05:49:07 EDT 2009
2009/10/22 zaxis <z_axis at 163.com>:
>
>>>replace k v xs = (k,v) : filter ((/=v) . fst) xs
> Great ! thanks you very much
I'm not sure why you're so much happy:
Assume some function defined as follow:
foo a b c = e x y z a b c
where x = some constant
y = some other constant
z = some other constant
'e' means just that the complete body of the function foo involves x,
y, z, a, b and c. Generalizing foo to let the caller choose the values
of x, y, z is just
foo a b c x y z = e x y z a b c
-- the where is unneeded
In fact, this is what functions are made for: generalizing a given
expression so that part of the expression can be given in arguements.
E.g. turning
e a b
into
f a = e a b
Cheers,
Thu
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