How can I step through this code?

How can I step through this code?

[jgart]

Hi

How can I step through this code?

(define-syntax do
  (syntax-rules ()
    ((do ((var init step ...) ...)
         (test expr ...)
         command ...)
     (letrec
       ((loop
         (lambda (var ...)
           (if test
               (begin
                 (if #f #f)
                 expr ...)
               (begin
                 command
                 ...
                 (loop (do "step" var step ...)
                       ...))))))
       (loop init ...)))
    ((do "step" x)
     x)
    ((do "step" x y)
     y)))

Re: How can I step through this code?

[jbranso]

October 5, 2022 11:06 PM, "jgart" <jgart@dismail.de> wrote:

> Hi
> 
> How can I step through this code?
> 

If you ever find out, then let me know!

I wish guile had a nice debugger like elisp.  :)

> (define-syntax do
> (syntax-rules ()
> ((do ((var init step ...) ...)
> (test expr ...)
> command ...)
> (letrec
> ((loop
> (lambda (var ...)
> (if test
> (begin
> (if #f #f)
> expr ...)
> (begin
> command
> ...
> (loop (do "step" var step ...)
> ...))))))
> (loop init ...)))
> ((do "step" x)
> x)
> ((do "step" x y)
> y)))

Re: How can I step through this code?

[jgart]

On Fri, 07 Oct 2022 18:45:36 +0000 jbranso@dismail.de wrote:
> I wish guile had a nice debugger like elisp.  :)

I wish guile had a nice debugger like racket or common lisp.  :)

Re: How can I step through this code?

[jbranso]

October 7, 2022 3:22 PM, "jgart" <jgart@dismail.de> wrote:

> On Fri, 07 Oct 2022 18:45:36 +0000 jbranso@dismail.de wrote:
> 
>> I wish guile had a nice debugger like elisp. :)
> 
> I wish guile had a nice debugger like racket or common lisp. :)

I haven't actually tried those debuggers...

Re: How can I step through this code?

[jgart]

On Fri, 07 Oct 2022 21:52:40 +0000 jbranso@dismail.de wrote:
> October 7, 2022 3:22 PM, "jgart" <jgart@dismail.de> wrote:
> 
> > On Fri, 07 Oct 2022 18:45:36 +0000 jbranso@dismail.de wrote:
> > 
> >> I wish guile had a nice debugger like elisp. :)
> > 
> > I wish guile had a nice debugger like racket or common lisp. :)
> 
> I haven't actually tried those debuggers...

Just paste some guile code into drracket and press debug to start stepping through the Guile code.

This guile code should work:

(define (list-index l k)
  (let loop ((n 0)
             (l l))
    (and (not (null? l))
         (if (eq? (car l) k)
             n
             (loop (+ n 1) (cdr l))))))

(list-index '(1 2 3 4 5 6 7 8 9) 2)

Just make sure you put the following at the top of the file:

#lang racket

Of course not all guile code would work because it's Guile and Racket
but some subsets of Guile can be used from the drracket debugger.

;()

Re: How can I step through this code?

[jbranso]

October 7, 2022 9:25 PM, "jgart" <jgart@dismail.de> wrote:

> On Fri, 07 Oct 2022 21:52:40 +0000 jbranso@dismail.de wrote:
> 
>> October 7, 2022 3:22 PM, "jgart" <jgart@dismail.de> wrote:
>> 
>> On Fri, 07 Oct 2022 18:45:36 +0000 jbranso@dismail.de wrote:
>> 
>> I wish guile had a nice debugger like elisp. :)
>> 
>> I wish guile had a nice debugger like racket or common lisp. :)
>> 
>> I haven't actually tried those debuggers...
> 
> Just paste some guile code into drracket and press debug to start stepping through the Guile code.

That's smart! 

> 
> This guile code should work:
> 
> (define (list-index l k)
> (let loop ((n 0)
> (l l))
> (and (not (null? l))
> (if (eq? (car l) k)
> n
> (loop (+ n 1) (cdr l))))))
> 
> (list-index '(1 2 3 4 5 6 7 8 9) 2)
> 
> Just make sure you put the following at the top of the file:
> 
> #lang racket
> 
> Of course not all guile code would work because it's Guile and Racket
> but some subsets of Guile can be used from the drracket debugger.
> 
> ;()

Re: How can I step through this code?

[jgart]

On Sat, 08 Oct 2022 15:03:54 +0000 jbranso@dismail.de wrote:
> That's smart! 

Did you try it? I've been trying to understand how some Guile code works
by just throwing it in the Racket debugger. It doesn't always work but
when it does it's like driving a fancy cadillac through the stack.

It's too bad that Guile's debugger sucks compared to Racket's debugger. Maybe
someday someone will implement something amazing for that.

RE The Common Lisp debugger: It's really great but it might be a rabbit hole.

I recommend using sly or slime with sbcl if you want to go down that.

Re: How can I step through this code?

[jbranso]

October 8, 2022 1:23 PM, "jgart" <jgart@dismail.de> wrote:

> On Sat, 08 Oct 2022 15:03:54 +0000 jbranso@dismail.de wrote:
> 
>> That's smart!
> 
> Did you try it? I've been trying to understand how some Guile code works
> by just throwing it in the Racket debugger. It doesn't always work but
> when it does it's like driving a fancy cadillac through the stack.

hahaha!  I have not tried it.   I definitely should.

I ran into this common problem yesterday.  I am of course simplifying:

(string-append "hello"
               (if some-var
                   " world\n"))

error: expecting type string
(string-append "hello" #unspecified)


It took me an embarrassing amount of time to track down where the 
#unspecified was coming from.

I feel like the error message was a little bit cryptic.  It said that 
one particular function cause the error...It just took me a while to track
it down.  A debugger stepping through the code would have been awesome!
 
> It's too bad that Guile's debugger sucks compared to Racket's debugger. Maybe
> someday someone will implement something amazing for that.
> 
> RE The Common Lisp debugger: It's really great but it might be a rabbit hole.
> 
> I recommend using sly or slime with sbcl if you want to go down that.

Right now I am super in love with Guix.  My main squeeze is working
on our existing opensmtpd-service and letting users configure it with
proper scheme records.  I don't know if I want to play with common lisp.

Thanks,

Joshua

Re: How can I step through this code?

[jgart]

On Sun, 09 Oct 2022 00:14:23 +0000 jbranso@dismail.de wrote:
> A debugger stepping through the code would have been awesome!

Yup it would have! You're right!

> Right now I am super in love with Guix.  

Me too, it's more like a passionate love hate relationship for me tbh. I
need couples GNUtherapy.

> My main squeeze is working
> on our existing opensmtpd-service and letting users configure it with
> proper scheme records.  I don't know if I want to play with common lisp.

Ya, it's a rabbit hole although I recommend atleast once, taking a stack
stroll in the caddy just so you know what's up ;()

Re: How can I step through this code?

[jbranso]

October 9, 2022 12:30 PM, "jgart" <jgart@dismail.de> wrote:

> On Sun, 09 Oct 2022 00:14:23 +0000 jbranso@dismail.de wrote:
> 
>> A debugger stepping through the code would have been awesome!
> 
> Yup it would have! You're right!
> 
>> Right now I am super in love with Guix.
> 
> Me too, it's more like a passionate love hate relationship for me tbh. I
> need couples GNUtherapy.
> 
>> My main squeeze is working
>> on our existing opensmtpd-service and letting users configure it with
>> proper scheme records. I don't know if I want to play with common lisp.
> 
> Ya, it's a rabbit hole although I recommend atleast once, taking a stack
> stroll in the caddy just so you know what's up ;()

ahaha.  I guess there is an OS written in common lisp...

Re: How can I step through this code?

[jgart]

On Mon, 10 Oct 2022 19:49:23 +0000 jbranso@dismail.de wrote:
> October 9, 2022 12:30 PM, "jgart" <jgart@dismail.de> wrote:
> 
> > On Sun, 09 Oct 2022 00:14:23 +0000 jbranso@dismail.de wrote:
> > 
> >> A debugger stepping through the code would have been awesome!
> > 
> > Yup it would have! You're right!
> > 
> >> Right now I am super in love with Guix.
> > 
> > Me too, it's more like a passionate love hate relationship for me tbh. I
> > need couples GNUtherapy.
> > 
> >> My main squeeze is working
> >> on our existing opensmtpd-service and letting users configure it with
> >> proper scheme records. I don't know if I want to play with common lisp.
> > 
> > Ya, it's a rabbit hole although I recommend atleast once, taking a stack
> > stroll in the caddy just so you know what's up ;()
> 
> ahaha.  I guess there is an OS written in common lisp...

ya anything rust can do CL could do better jk (not jk)

Re: How can I step through this code?

[Ludovic Courtès]

Hi,

jgart <jgart@dismail.de> skribis:

> How can I step through this code?
>
> (define-syntax do
>   (syntax-rules ()
>     ((do ((var init step ...) ...)
>          (test expr ...)
>          command ...)
>      (letrec
>        ((loop
>          (lambda (var ...)
>            (if test
>                (begin
>                  (if #f #f)
>                  expr ...)
>                (begin
>                  command
>                  ...
>                  (loop (do "step" var step ...)
>                        ...))))))
>        (loop init ...)))
>     ((do "step" x)
>      x)
>     ((do "step" x y)
>      y)))

You can’t: this is a macro and Guile doesn’t have a “macro stepper”
(Racket does).

What you can do though, is define the macro and expand it on examples of
your choosing to see how it behaves:

--8<---------------cut here---------------start------------->8---
scheme@(guile-user)> ,expand (do ((x 0 (+ 1 x))) ((>= x 10)) (pk x))
$7 = (let loop ((x 0))
  (if (>= x 10)
    (if #f #f)
    (begin (pk x) (loop (+ 1 x)))))
scheme@(guile-user)> ,optimize (do ((x 0 (+ 1 x))) ((>= x 10)) (pk x))
$8 = (begin
  (pk 0)
  (pk 1)
  (pk 2)
  (pk 3)
  (pk 4)
  (pk 5)
  (pk 6)
  (pk 7)
  (pk 8)
  (pk 9)
  (if #f #f))
--8<---------------cut here---------------end--------------->8---

(Personally I’ve never used ‘do’ and I don’t feel like starting today. :-))

Ludo’.

Re: How can I step through this code?

[jgart]

On Mon, 10 Oct 2022 18:04:57 +0200 Ludovic Courtès <ludo@gnu.org> wrote:
> What you can do though, 

Thanks Ludo! Much appreciated!! I hadn't used ,optimize metacommand yet. I've used
pk in Guile and Racket but not regularly tbh. Maybe I should start.

Ludo, how would you step through this code?

(define (list-index l k)
  (let loop ((n 0)
             (l l))
    (and (not (null? l))
         (if (eq? (car l) k)
             n
             (loop (+ n 1) (cdr l))))))

(list-index '(1 2 3 4 5 6 7 8 9) 2)

What is your approach with Guile?

all best,

jgart