Re: Multi-language scripts

[Matt Wette <matt.wette@gmail.com>]

On 8/22/20 7:53 AM, Stephen Scheck wrote:
> Matt Wette wrote:
>
>> maybe this?
>>
>> (use-modules (system base language))
>> (current-language (lookup-language 'ecmascript))
> It doesn’t work:
>
>      scheme@(guile-user)> (use-modules (system base language))
>      scheme@(guile-user)> (lookup-language ‘ecmascript)
>      $1 = #<<language> name: ecmascript title: ECMAScript reader: #<procedure 7f939b1bb558 at language/ecmascript/spec.scm:33:16 (port env)> printer: #<procedure write (_ #:optional _)> parser: #f compilers: ((tree-il . #<procedure compile-tree-il (exp env opts)>)) decompilers: () evaluator: #f joiner: #f for-humans?: #t make-default-environment: #<procedure make-fresh-user-module ()>>
>      scheme@(guile-user)> (current-language $1)
>      $2 = scheme
>      scheme@(guile-user)> display("We should be in JavaScript now, but we aren’t!\n”);
>      $3 = #<procedure display (_ #:optional _)>
>      ERROR: Wrong type to apply: "We should be in JavaScript now, but we aren’t!\n”
>      
>      Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
>
>
> Also, even if it did, it would be problematic switching back - you’d need to do something along these lines in Scheme first:
>
> (define (string_to_symbol sym) (string->symbol sym))
> (define (lookup_language lang) (lookup-language lang))
> (define (set_current_language lang) (set-current-language! lang)) ;; assuming set-current-language! actually existed…
>
> This wouldn’t work, obviously, in the general case for other languages. I don’t really want to use JavaScript, I was just using it as an example.
>
> I really just want some way to enable the REPL reader when you pass a script to Guile with the -s switch from the command line so you can embed `,language` meta-commands in the script file.
>
>
I think the issue is that while the repl processes one input (line) at a 
time guile
handles files by compiling a file at a time.  I think you'd have to 
write code
to process files an input (line) at a time.  Maybe this could be a 
procedure that
takes the name of the file, generates a repl and feeds the repl from the 
file
one line at a time.

(I have played with the compiler code a bit in writing guile-hosted 
parser/interpreters
for javascript, matlab, tcl and others.   Try web search for guile nyacc.)

Matt