Re: Scheme question: convert a range

[Jacques Menu]

Message says that #(string-append… is not a markup.

> Le 17 nov. 2015 à 13:31, Jacques Menu <address@hidden> a écrit :
> 
> Hello folks,
> 
> I’ve tried to integrate such a pure Scheme function:
> 
> 
> guile> (define (function arg)
>   (if (and (integer? (car arg)) (integer? (cdr arg)))
>       (iota (1+ (interval-length arg)) (car arg) 1)
>       )
>   )
> guile> (function '(3 . 7))
> (3 4 5 6 7)
> 
> 
> as part of a markup, but to no avail. Here is one of my attempts:
> 
> 
> \version "2.19.30"
> 
> #(define (function arg)
>   (if (and (integer? (car arg)) (integer? (cdr arg)))
>       (iota (1+ (interval-length arg)) (car arg) 1)
>       )
>   )
> 
> {
>  c'1 -\markup {
>    \column {
>      \column {
>        #(string-append
>          "commllen = " (list->sting (map #'number->string (function '(3 . 
> 7))))
>          )
>      }
>    }
>  }
> }
> 
> 
> Thanks for your help!
> 
> JM
> 
>> Le 17 nov. 2015 à 02:10, Andrew Bernard <address@hidden> a écrit :
>> 
>> Hi Simon,
>> 
>> Fellow listers have posted many answers while I was cooking up this one. All 
>> good!
>> 
>> 
>> (use-modules (srfi srfi-1))
>> 
>> (define (range r)
>>      (let ((start (car r))
>>      (end (cdr r)))
>>      (iota (+ (- end start) 1) start 1)))
>> 
>> That’s pure Scheme of course. Thomas Morley’s answer is more in the 
>> vernacular of lilypond. But I just wanted to point out the list functions 
>> you would expect to exist but don’t in R5RS are in SRFI-1. But lilypond 
>> looks after all that for you.
>> 
>> 
>> The purely recursive solutions are nice, because lists are intrinsically 
>> recursively defined, but Functional programmers tend avoid doing that and 
>> prefer to hide the recursion behind generalised functions such as iota. A 
>> lot easier on the brain and the maintainer. Just a matter of FP style. There 
>> are many views!
>> 
>> Andrew
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
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>