Re: [FEATURE] List all available languages

[Andy Wingo <wingo@pobox.com>]

On Fri 25 Jan 2013 11:43, Nala Ginrut <nalaginrut@gmail.com> writes:

> @@ -33,6 +33,9 @@
>  
>  (define-module (ice-9 command-line)
>    #:autoload (system vm vm) (set-default-vm-engine! set-vm-engine! the-vm)
> +  #:use-module (srfi srfi-1)
> +  #:use-module (ice-9 regex)
> +  #:use-module (ice-9 ftw)
>    #:export (compile-shell-switches
>              version-etc
>              *GPLv3+*

For the reason given in the comment above this block, we cannot load
these modules at startup.  (Too expensive.)  I suggest you make a little
trampoline that does a module-ref at runtime like eval-string/lang.

> +(define (not-inner-lang? str)
> +  (not (string-match 
> +	"glil|glil\\.scm|assembly|assembly\\.scm|bytecode|objcode\\.scm|objcode|tree-il|tree-il\\.scm|value|\\.\\.|\\." 
> +	str)))
> +
> +(define (get-all-available-languages)
> +  (let lp((rest (map (lambda (x) (string-append x "/language")) %load-path)) (result '()))
> +    (cond
> +     ((null? rest) (apply lset-union string=? result))
> +     (else 
> +      (let ((ll (scandir (car rest) not-inner-lang?)))
> +	(lp (cdr rest) (if ll (cons ll result) result)))))))

This is pretty nasty :)  First of all I would request that you have no
tabs please and stick to the 80-char limit.  But more substantially I
would want a function that returns a list of symbols and calls
lookup-language on them, recursively filtering out any language that is
the target of another compiler.

> +           ((string=? "--list-languages" arg) ; list all languages
> +            (for-each (lambda (l)
> +                        (format #t "~a~%" l))
> +                      (get-all-available-languages))
> +            (exit 0))
> +

Also this needs to respect the 80-character width, somehow.

> +(define (valid-lang? str)
> +  (not (string-match 
> +	"[A-Za-z0-9_ -]+\\.scm|\\.\\.|\\." 
> +	str)))
> +
> +(define (get-all-available-languages)
> +  (let lp((rest (map (lambda (x) (string-append x "/language")) %load-path)) (result '()))
> +    (cond
> +     ((null? rest) (apply lset-union string=? result))
> +     (else 
> +      (let ((ll (scandir (car rest) valid-lang?)))
> +	(lp (cdr rest) (if ll (cons ll result) result)))))))
> +

Why is this duplicated here?

> +  -l, --list-languages list all available languages

Probably we don't need the short option.

Regards,

Andy
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