[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: GOOPS functional setter

From: Jan Nieuwenhuizen
Subject: Re: GOOPS functional setter
Date: Fri, 13 Jan 2017 22:33:05 +0100
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux)

Christopher Allan Webber writes:

> I guess I never sent this to this list.  Here's a functional setter for
> GOOPS classes.

Hah!  Just this week I have been wondering the perceived absense of
functional setters (and figured I *must* have missed something
somewhere) and wrote

--8<---------------cut here---------------start------------->8---
(define ((identity-initializer o) name)
  (list (symbol->keyword name) (slot-ref o name))) 

(define-method (clone o . setters)
 (let* ((class (class-of o))
        (slots (class-slots class))
        (names (map slot-definition-name slots))
        (initializers (map (identity-initializer o) names))
        (keywords (filter keyword? setters))
        (initializers (filter (lambda (i) (not (memq (car i) keywords))) 
        (initializers (append (apply append initializers) setters))
        (arguments (cons class initializers)))
   (apply make arguments)))
--8<---------------cut here---------------end--------------->8---


   (clone o #:slot <VALUE> ...)

Jan Nieuwenhuizen <address@hidden> | GNU LilyPond
Freelance IT | AvatarĀ®  

reply via email to

[Prev in Thread] Current Thread [Next in Thread]