Re: define anywhere

[Damien Mattei <damien.mattei@gmail.com>]

hello Linus,

finally i tested your code with my program and it works.

define worked in if in ssigma-sol-approx
( in


*Preview:*

;; (load "SssRec.scm")


;;(use-modules (syntax define));;(use-modules
(guile/define))(use-modules (guile define))
(include "first-and-rest.scm")(include "list.scm")(include
"postfix.scm")(include "let.scm")(include "definition.scm")(include
"guile/array.scm")(include "block.scm")
;; if data are disordered the algo works also
;; scheme@(guile-user)> (define L-init '(1 3 4 16 17 64 256 275 723
889 1040 1041 1093 1111 1284 1344 1520 2027 2734 3000 4285 5027));;
scheme@(guile-user)>  (start-ssigma-sol-approx-linus L-init 19836);;
$1 = (1 3 4 16 17 256 275 723 1040 1041 1284 1344 1520 3000 4285
5027)(define (start-ssigma-sol-approx-linus L t) ;; Sub Set Sum
problem (find solution or approximation)
  ;; { } are for infix notation as defined in SRFI 105
  ;; <+ and := are equivalent to (define var value)
  { best-sol <+ (lambda (L1 L2)
		
		  {s1 <+ (apply + L1)}
		  {s2 <+ (apply + L2)}
		
		  (if {(abs {t - s1}) <= (abs {t - s2})}
		      L1
		      L2)) }

  ;; := is the same macro as <+
  { best-sol3 := (lambda (L1 L2 L3)
		
		   {L22 <+ (best-sol L2 L3)}
		   (best-sol L1 L22)) }


  { ssigma-sol-approx <+ (lambda (L)
			   ;; def is a macro for declared but unasigned variable, it is
same as (define var '())
			   ;;(def c)
			   ;;(def R)
			
			   (if (null? L)
			       L
			       ($ (define c (first L)) ;; $ = begin
				  (if {c = t}
				      (list c)  ;; c is the solution
				      ($ (define R (rest L))
					 (if {c > t}
					     (best-sol (list c) (ssigma-sol-approx R))  ;; c is to big to
be a solution but could be an approximation
					     ;; c < t at this point, 3 possibilities :
					     ;; c is the best solution
					     ;; c is part of the solution or his approximation
					     ;; or c is not part of solution or his approximation
					     (best-sol3 (list c) ;; c is the best solution
							;; c part of solution or is approximation
							(cons c (start-ssigma-sol-approx-linus R {t - c})) ;; we have
to find a solution or an approximation for t-c now
							;; c is not part of solution or his approximation
							(ssigma-sol-approx R)))))))) }
		
	
  ;; start the function
  (ssigma-sol-approx L))



without you module, my solution was:

https://github.com/damien-mattei/library-FunctProg/blob/master/SssRec.scm

*Preview:*

;; scheme@(guile-user)> (define L-init '(1 3 4 16 17 64 256 275 723
889 1040 1041 1093 1111 1284 1344 1520 2027 2734 3000 4285 5027));;
scheme@(guile-user)>  (start-ssigma-sol-approx-basic L-init 19836);;
$1 = (1 3 4 16 17 256 275 723 1040 1041 1284 1344 1520 3000 4285
5027);; scheme@(guile-user)> (apply + $1);; $2 = 19836(define
(start-ssigma-sol-approx-basic L t) ;; Sub Set Sum problem (find
solution or approximation)
  ;; { } are for infix notation as defined in SRFI 105
  ;; <+ and := are equivalent to (define var value)
  { best-sol <+ (lambda (L1 L2)
		
		  {s1 <+ (apply + L1)}
		  {s2 <+ (apply + L2)}
		
		  (if {(abs {t - s1}) <= (abs {t - s2})}
		      L1
		      L2)) }

  ;; := is the same macro as <+
  { best-sol3 := (lambda (L1 L2 L3)
		
		   {L22 <+ (best-sol L2 L3)}
		   (best-sol L1 L22)) }


  { ssigma-sol-approx <+ (lambda (L)
			   ;; def is a macro for declared but unasigned variable, it is
same as (define var '())
			   (def c)
			   (def R)
			
			   (if (null? L)
			       L
			       ($ {c <- (first L)} ;; $ = begin
				  (if {c = t}
				      (list c)  ;; c is the solution
				      ($ {R <- (rest L)}
					 (if {c > t}
					     (best-sol (list c) (ssigma-sol-approx R))  ;; c is to big to
be a solution but could be an approximation
					     ;; c < t at this point, 3 possibilities :
					     ;; c is the best solution
					     ;; c is part of the solution or his approximation
					     ;; or c is not part of solution or his approximation
					     (best-sol3 (list c) ;; c is the best solution
							;; c part of solution or is approximation
							(cons c (start-ssigma-sol-approx-basic R {t - c})) ;; we have
to find a solution or an approximation for t-c now
							;; c is not part of solution or his approximation
							(ssigma-sol-approx R)))))))) }
		
	
  ;; start the function
  (ssigma-sol-approx L))


just had a few problem making Guile 3.0 find the module from an other sub
directory, but not the falt of you module, my config i think?


Damien


On Sat, Jun 5, 2021 at 5:24 PM Linus Björnstam <linus.internet@fastmail.se>
wrote:

> I implemented this hack before guile 3 got defines in function bodies:
> https://hg.sr.ht/~bjoli/guile-define
>
> Even I guile 3 it allows a more liberal placement of define, but it won't
> work for things like bodies of imported macros (like match)
> --
>   Linus Björnstam
>
> On Sat, 5 Jun 2021, at 00:27, Damien Mattei wrote:
> > hello,
> > i'm was considering that i want to be able to define a variable
> > anywhere in
> > code, the way Python do. Few scheme can do that (Bigloo i know)
> > ( the list here is not exact:
> >
> https://www.reddit.com/r/scheme/comments/b73fdz/placement_of_define_inside_lambda_bodies_in/
> > )
> >  is it possible in guile to do it? i do not know, so could it be added
> > to
> > the language specification for future release?
> >
> > regards,
> > Damien
> >
>