support thunks as prompts without readline

support thunks as prompts without readline

[Andy Wingo]

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Hi,


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From 69fc67efaad628a866e14ead4cb96f102316b82b Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 9 May 2008 16:42:44 +0200
Subject: [PATCH] support thunks as prompts, as readline does.

* ice-9/boot-9.scm (repl-reader): Support thunks as prompts.
---
 ice-9/boot-9.scm |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/ice-9/boot-9.scm b/ice-9/boot-9.scm
index d1e6306..b92cfd6 100644
--- a/ice-9/boot-9.scm
+++ b/ice-9/boot-9.scm
@@ -2518,7 +2518,7 @@
 ;;; the readline library.
 (define repl-reader
   (lambda (prompt)
-    (display prompt)
+    (display (if (string? prompt) prompt (prompt)))
     (force-output)
     (run-hook before-read-hook)
     ((or (fluid-ref current-reader) read) (current-input-port))))
-- 
1.5.5-rc2.GIT


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Re: support thunks as prompts without readline

[Neil Jerram]

Andy Wingo <wingo@pobox.com> writes:

> * ice-9/boot-9.scm (repl-reader): Support thunks as prompts.
> ---
>  ice-9/boot-9.scm |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/ice-9/boot-9.scm b/ice-9/boot-9.scm
> index d1e6306..b92cfd6 100644
> --- a/ice-9/boot-9.scm
> +++ b/ice-9/boot-9.scm
> @@ -2518,7 +2518,7 @@
>  ;;; the readline library.
>  (define repl-reader
>    (lambda (prompt)
> -    (display prompt)
> +    (display (if (string? prompt) prompt (prompt)))
>      (force-output)
>      (run-hook before-read-hook)
>      ((or (fluid-ref current-reader) read) (current-input-port))))

I don't get this one.  Isn't the thunk option already covered by the
code that calls repl-reader, here:

			   (let ((prompt (cond ((string? scm-repl-prompt)
						scm-repl-prompt)
					       ((thunk? scm-repl-prompt)
						(scm-repl-prompt))
					       (scm-repl-prompt "> ")
					       (else ""))))
			     (repl-reader prompt))))

Regards,
     Neil

Re: support thunks as prompts without readline

[Andy Wingo]

Hey Neil,

On Sat 10 May 2008 00:36, Neil Jerram <neil@ossau.uklinux.net> writes:

> Andy Wingo <wingo@pobox.com> writes:
>
>> * ice-9/boot-9.scm (repl-reader): Support thunks as prompts.
>> ---
>>  ice-9/boot-9.scm |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/ice-9/boot-9.scm b/ice-9/boot-9.scm
>> index d1e6306..b92cfd6 100644
>> --- a/ice-9/boot-9.scm
>> +++ b/ice-9/boot-9.scm
>> @@ -2518,7 +2518,7 @@
>>  ;;; the readline library.
>>  (define repl-reader
>>    (lambda (prompt)
>> -    (display prompt)
>> +    (display (if (string? prompt) prompt (prompt)))
>>      (force-output)
>>      (run-hook before-read-hook)
>>      ((or (fluid-ref current-reader) read) (current-input-port))))
>
> I don't get this one.  Isn't the thunk option already covered by the
> code that calls repl-reader, here:
>
> 			   (let ((prompt (cond ((string? scm-repl-prompt)
> 						scm-repl-prompt)
> 					       ((thunk? scm-repl-prompt)
> 						(scm-repl-prompt))
> 					       (scm-repl-prompt "> ")
> 					       (else ""))))
> 			     (repl-reader prompt))))

Sorry for the long quote. Answer: It does seem that this case is covered
by the scm-style REPL. I'm trying to use the repl-reader for a different
repl, the one in guile-vm. The (ice-9 readline) repl-reader does handle
the prompt-as-thunk case. I just want them both to act the same :)

I could change to call the thunk instead, if that's the best option.
Please advise as to what you want to accept.

Andy
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http://wingolog.org/

Re: support thunks as prompts without readline

[Neil Jerram]

Andy Wingo <wingo@pobox.com> writes:

>> 			   (let ((prompt (cond ((string? scm-repl-prompt)
>> 						scm-repl-prompt)
>> 					       ((thunk? scm-repl-prompt)
>> 						(scm-repl-prompt))
>> 					       (scm-repl-prompt "> ")
>> 					       (else ""))))
>> 			     (repl-reader prompt))))
>
> Sorry for the long quote. Answer: It does seem that this case is covered
> by the scm-style REPL. I'm trying to use the repl-reader for a different
> repl, the one in guile-vm. The (ice-9 readline) repl-reader does handle
> the prompt-as-thunk case. I just want them both to act the same :)
>
> I could change to call the thunk instead, if that's the best option.
> Please advise as to what you want to accept.

What about moving the cond above from the caller to inside
repl-reader?  I'd be happy with that, and I think it would meet your
needs, wouldn't it?

    Neil