Re: bug#13077: guile: add repl-option for customized print

[nalaginrut <nalaginrut@gmail.com>]

Hi Daniel!
I believe this patch simplified my work, and 'colorized' module has been
finished, I'm testing and debugging.
I'll post it when it's all done.

Thanks!

On Tue, 2012-12-04 at 11:46 +0800, Daniel Hartwig wrote:
> Package: guile
> Severity: wishlist
> Tags: patch
> X-Debbugs-CC: nalaginrut <nalaginrut@gmail.com>
> 
> Dear maintainer
> 
> The attached patch adds a new repl-option to set a custom print
> procedure.
> 
> --
> scheme@(guile-user)> (use-modules (srfi srfi-1))
> scheme@(guile-user)> (iota 20)
> $1 = (0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19)
> scheme@(guile-user)> (define (repl-print* repl val)
>                        (if (not (eq? val *unspecified*))
>                            (begin
>                              (run-hook before-print-hook val)
>                              (format #t "~20@y" val)
>                              (newline))))
> scheme@(guile-user)> (use-modules (system repl common))
> scheme@(guile-user)> (repl-option-set! (car (fluid-ref *repl-stack*)) 'print repl-print*)
> scheme@(guile-user)> (iota 20)
> $2 = (0 1 2 3 4 5 6 7 …)
> differences between files attachment
> (0001-repl-add-repl-option-for-customized-print.patch)
> From b0cadcb69a12a4ed2a205f4854af41bf926da20b Mon Sep 17 00:00:00 2001
> From: Daniel Hartwig <mandyke@gmail.com>
> Date: Tue, 4 Dec 2012 11:41:35 +0800
> Subject: [PATCH] repl: add repl-option for customized print
> 
> * module/system/repl/common.scm (repl-default-options)
>   (repl-print): Add option to use customized print procedure.
> * doc/ref/scheme-using.texi (REPL Commands): Update.
> ---
>  doc/ref/scheme-using.texi     |    4 ++++
>  module/system/repl/common.scm |   26 +++++++++++++++++---------
>  2 files changed, 21 insertions(+), 9 deletions(-)
> 
> diff --git a/doc/ref/scheme-using.texi b/doc/ref/scheme-using.texi
> index 7eb84de..4f9e6db 100644
> --- a/doc/ref/scheme-using.texi
> +++ b/doc/ref/scheme-using.texi
> @@ -445,6 +445,10 @@ choice is available.  Off by default (indicating compilation).
>  @item prompt
>  A customized REPL prompt.  @code{#f} by default, indicating the default
>  prompt.
> +@item print
> +A procedure of two arguments used to print the result of evaluating each
> +expression.  The arguments are the current REPL and the value to print.
> +By default, @code{#f}, to use the default procedure.
>  @item value-history
>  Whether value history is on or not.  @xref{Value History}.
>  @item on-error
> diff --git a/module/system/repl/common.scm b/module/system/repl/common.scm
> index 346ba99..fd41b09 100644
> --- a/module/system/repl/common.scm
> +++ b/module/system/repl/common.scm
> @@ -119,6 +119,11 @@ See <http://www.gnu.org/licenses/lgpl.html>, for more details.")
>                      ((thunk? prompt) (lambda (repl) (prompt)))
>                      ((procedure? prompt) prompt)
>                      (else (error "Invalid prompt" prompt)))))
> +     (print #f ,(lambda (print)
> +                  (cond
> +                   ((not print) #f)
> +                   ((procedure? print) print)
> +                   (else (error "Invalid print procedure" print)))))
>       (value-history
>        ,(value-history-enabled?)
>        ,(lambda (x)
> @@ -206,15 +211,18 @@ See <http://www.gnu.org/licenses/lgpl.html>, for more details.")
>      (% (thunk))))
>  
>  (define (repl-print repl val)
> -  (if (not (eq? val *unspecified*))
> -      (begin
> -        (run-hook before-print-hook val)
> -        ;; The result of an evaluation is representable in scheme, and
> -        ;; should be printed with the generic printer, `write'. The
> -        ;; language-printer is something else: it prints expressions of
> -        ;; a given language, not the result of evaluation.
> -	(write val)
> -	(newline))))
> +  (cond
> +   ((repl-option-ref repl 'print)
> +    => (lambda (print) (print repl val)))
> +   ((not (eq? val *unspecified*))
> +    (begin
> +      (run-hook before-print-hook val)
> +      ;; The result of an evaluation is representable in scheme, and
> +      ;; should be printed with the generic printer, `write'. The
> +      ;; language-printer is something else: it prints expressions of
> +      ;; a given language, not the result of evaluation.
> +      (write val)
> +      (newline)))))
>  
>  (define (repl-option-ref repl key)
>    (cadr (or (assq key (repl-options repl))