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Re: unhandled constant?

From: Ricardo Wurmus
Subject: Re: unhandled constant?
Date: Wed, 29 Jan 2020 16:06:23 +0100
User-agent: mu4e 1.2.0; emacs 26.3

Han-Wen Nienhuys <address@hidden> writes:

> Some of the lilypond Scheme files do the following:
> (define decl '())
> (define (make-var n v) (list "var" n v))
> (defmacro define-session (name value)
>   (define (inner n v)
>     (set! decl
>         (cons
>          (make-var n v)
>          decl))
>     )
>   `(,inner ',name ,value))
> (define-session foo 1)
> (display decl)
> (newline)
> In GUILE 2.2, this yields
> ;;; WARNING: compilation of /home/hanwen/vc/lilypond/q.scm failed:
> ;;; unhandled constant #<procedure inner (a b)>
> What does this error message mean, and what should I do to address the 
> problem?

Would it be feasible to use define-syntax-rule here?

--8<---------------cut here---------------start------------->8---
(define decl '())
(define (make-var n v) (list "var" n v))
(define-syntax-rule (define-session name value)
  (let ((inner (lambda (n v)
                 (set! decl
                        (make-var n v)
    (inner 'name value)))
(define-session foo 1)
(display decl)
--8<---------------cut here---------------end--------------->8---


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