That'll do the trick. Just to rearrange a bit, the following seems to
come closest in spirit to the function composition operator:
CADR = {Compose CAR CDR}
Whereas you don't get the sugar of defining a new operator, you do get
the same expressive power with the added bonus of consistency.
Thanks!
Chris Rathman
Kevin Glynn wrote:
Chris Rathman writes:
> More of curiosity question at the moment as I attempt to translate SICP,
> but does Oz have he ability to compose functions in the manner of
> composition operator? Taking a simple ML example:
>
> val car = hd
> val cdr = tl
> val cadr = car o cdr
>
> And extrapolating that idea to my pseudo Oz code, I'd have something
> along the lines of:
>
> fun {CAR L} L.1 end
> fun {CDR L} L.2 end
> fun {CADR L} CAR o CDR end
>
> To relate the question to CTM, the book gives a Haskell example in
> section 4.7.2 that has an expression within the sqrt function:
>
> dropWhile (not . gooEnough)
>
> where the dot operator in Haskell does effectively the same that the o
> operator does above.
>
Hi Chris,
There is no compose operator in Mozart/Oz and, unlike Haskell, you
can't add your own new operators. However, compose is just an
ordinary higher orderfunction, so:
fun {Compose F G}
fun {$ X}
{F {G X}}
end
end
fun {CAR L} L.1 end
fun {CDR L} L.2 end
fun {CADR L} {{Compose CAR CDR} L} end
and
{List.dropWhile [1 2 3] {Compose Not IsEven}}
It is certainly a bit noisier than ML or Haskell, but the effect is
the same.
cheers
k
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