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tiny usable ycombinator

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  tiny usable ycombinator humptydumpty <ouatubi@gmail.com> - 2015-04-04 14:39 -0700
    Re: tiny usable ycombinator Paul Rubin <no.email@nospam.invalid> - 2015-04-05 11:15 -0700
      Re: tiny usable ycombinator humptydumpty <ouatubi@gmail.com> - 2015-04-05 12:55 -0700
        Re: tiny usable ycombinator franck.bensusan@gmail.com - 2015-04-06 01:35 -0700
    Re: tiny usable ycombinator "WJ" <w_a_x_man@yahoo.com> - 2015-04-05 19:38 +0000
      Re: tiny usable ycombinator Paul Rubin <no.email@nospam.invalid> - 2015-04-05 12:50 -0700

#37946 — tiny usable ycombinator

Hi!

Fooling around I arrived at some small, usable and beauty ycombinator (gforth code):


: YC >R :noname R> compile, ]] dup execute ; [[ ;


Example of use, calculate 5 factorial :


1 5 :noname  ( 1 n xt -- partfact m xt| )  >r dup 1 > IF tuck * swap 1- r> ELSE 2rdrop THEN ; YC dup execute drop . 120  ok


Have a nice day,
humptydumpty

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#37970

humptydumpty <ouatubi@gmail.com> writes:
> 1 5 :noname ( 1 n xt -- partfact m xt| ) >r dup 1 > IF tuck * swap 1-
> r> ELSE 2rdrop THEN ; YC dup execute drop . 120 ok

OMG :-)

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#37978

On Sunday, April 5, 2015 at 9:15:39 PM UTC+3, Paul Rubin wrote:
> humptydumpty <> writes:
> > 1 5 :noname ( 1 n xt -- partfact m xt| ) >r dup 1 > IF tuck * swap 1-
> > r> ELSE 2rdrop THEN ; YC dup execute drop . 120 ok
> 
> OMG :-)

Isn't that cool? ;-)

That is just my laziness, I just posted line from terminal.

Could be something like:

: YC >R :noname R> compile, ]] dup execute ; [[ ; 

:noname  ( comment... )
    >r dup 1 > IF tuck * swap 1- r> ELSE 2rdrop THEN
; YC CONSTANT yc.factorial ( m n -- m*n! 1 ;bla-bla )

, and when needed kick-it in action ycombinator-way:

1 5 yc.factorial dup execute

Have a nice day,
humptydumpty

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#38001

Le dimanche 5 avril 2015 21:55:56 UTC+2, humptydumpty a écrit :
> On Sunday, April 5, 2015 at 9:15:39 PM UTC+3, Paul Rubin wrote:
> > humptydumpty <> writes:
> > > 1 5 :noname ( 1 n xt -- partfact m xt| ) >r dup 1 > IF tuck * swap 1-
> > > r> ELSE 2rdrop THEN ; YC dup execute drop . 120 ok
> > 
> > OMG :-)
> 
> Isn't that cool? ;-)
> 
> That is just my laziness, I just posted line from terminal.
> 
> Could be something like:
> 
> : YC >R :noname R> compile, ]] dup execute ; [[ ; 
> 
> :noname  ( comment... )
>     >r dup 1 > IF tuck * swap 1- r> ELSE 2rdrop THEN
> ; YC CONSTANT yc.factorial ( m n -- m*n! 1 ;bla-bla )
> 
> , and when needed kick-it in action ycombinator-way:
> 
> 1 5 yc.factorial dup execute
> 
> Have a nice day,
> humptydumpty

Yes, very very cool !!! Great job !

btw, in Oforth, you could write something like this : 
(non stateless Y, but you can also define a stateless Y).

func: Y(f) { #[ Y(f) f perform ] }

Now fact definition : 

func: almost-fact(f, n) { n ifZero: [ 1 ] else: [ n n 1 - f perform * ] }
func: fact { #almost-fact Y perform }

5 fact println
120

Franck

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#37975

humptydumpty wrote:

> Example of use, calculate 5 factorial :
> 
> 
> 1 5 :noname  ( 1 n xt -- partfact m xt| )
>  >r dup 1
> > IF tuck * swap 1- r> ELSE 2rdrop THEN ; YC dup execute drop . 120  ok

Oforth:

 > 1 #* 5 seq apply .s
 [1] (Integer) 120

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#37977

"WJ" <w_a_x_man@yahoo.com> writes:
> Oforth:
>  > 1 #* 5 seq apply .s
>  [1] (Integer) 120

That misses the point.  You are supposed to do this without using any
iteration or recursion, including "seq" which works iteratively or
recursively under the hood.

https://en.wikipedia.org/wiki/Fixed-point_combinator

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