Hi, Elan,
you wrote:
Hi Ladislav,
>look at this example:
>
>;Identity function, simply duplicates it's input
>id: func [x [number!]] [:x]
>;Increment function, increases it's input by one
>inc: func [x [number!]] [x + 1]
>;The same function as argument
>samef: func [f [any-function!]] [func [x] [f x]]
You comment on this function saying that it is "The same function as
argument". The same function as argument? I'm not sure what that is
supposed to mean. Perhaps you mean that it returns the same function it was
passed? I'll assume that's what you mean. Correct me if I'm wrong.
>a: samef :id
>;and now it comes:
Wait. Wait. You've got a little bug! If samef indeed is suppsed to return
the same function it was passed, samef should be defined like this:
-----------
I am sorry, but your approach is worth nothing,
it's too trivial.
With it you can define *only* the same function, but nothing like:
;composition of two functions
o: func [f g] [func [x] [f g x]]
;or shiftarg
shiftarg: func [f] [func [x] [f x + 1]
And, besides, where did you find that my code is prohibited?
-----------
samef: func [ f [any-function!] ] [
make function! first :f second :f
]
>> a: samef :id
>> a 1
== 1
>> a 2
== 2
>> b: samef :inc
>> b 1
== 2
>> b 2
== 3
And now for the grand finale:
>> a 1
== 1
>> a 2
== 2
Why mine works? Or better, why yours doesn't?
Using your version of samef:
>> samef: func [f [any-function!]] [func [x] [f x]]
>> a: samef :id
>> source a
a: func [x][f x]
>> b: samef :inc
>> source b
b: func [x][f x]
>> same? get first second :a get first second :b
== true
Using my version of samef:
>> samef: func [ f [any-function!] ] [
[ make function! first :f second :f
[ ]
>> a: samef :id
>> b: samef :inc
>> source a
a: func [x][x]
>> source b
b: func [x][x + 1]
Hope this helps.
Elan
------
sorry, it doesn't 8^(
see above, or have a good look at curried functions
------
Ladislav
