Re: Geting the list of MIDI instrument names

[Ralf Mattes]

On Wed, 20 Feb 2008 18:38:22 +0100, Reinhold Kainhofer wrote:

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> Am Dienstag, 19. Februar 2008 schrieb Ralf Mattes:
>> BTW, I think there is a bug in your invocation of 'format - the stream
>> parameter is missing. And you don't need 'display, #t as a stream
>> designator resolves to (current-output-port). Substitute #t with
>> (current-error-port) to send the list to standard error.
> 
> Well, you are right that it can be done simpler:
> #(map (lambda (x) (format #t "~s~%" (car x))) instrument-names-alist)
> 
> However, the "missing" #t is not a bug, rather a missing optimization. format 
> without a stream designator returns the formatted string, so in this case one 
> really needs a display. However, if you add the stram designator directly to 
> format, it's much shorter (unfortunately, both books on scheme that I have 
> borrowed from the library don't list this, so I didn't know about this until 
> now....).
> 

Are you shure about this? I've to admit that my Scheme is a bit rusty
(living mostly in Common Lisp these days), but that sounds wrong to me. 
IIRC format with a stream designator of NIL/#f returns the formated string.
Here's my little test case:

 ralf$ guile 
guile> ;;; With #t
... (format #t "foo")
fooguile> ;;; With #f
... (format #f "foo")
"foo"
guile> ;;; Your code 
... (format "foo")

Backtrace:
In current input:
   9: 0* [simple-format "foo"]

<unnamed port>:9:1: In procedure simple-format in expression (format "foo"):
<unnamed port>:9:1: Wrong number of arguments to #<primitive-procedure 
simple-format>
ABORT: (wrong-number-of-args)
guile> 



 Hmm, don't really see how your format invocation could possibly be
 implemented  ...

  Cheers, RalfD

> Reinhold
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> Reinhold Kainhofer, Vienna University of Technology, Austria email:
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