CODEWITHSUNDEEP
racket
JRR
JRR

Reputation: 6152

redefining one of the existing racket forms

I'm designing a new language and would like to re-define the procedural form of define but export the standard expression form as well. Is there a way I can do that? So far I have this code:

(define-syntax-rule (my-define (name args) body ...) ...)

(provide (rename-out [my-define define]) define)

but generates the error "identifier already provided (as a different binding) in: define"

Upvotes: 2

Views: 79

Answers (1)

soegaard
soegaard

Reputation: 31147

Here is an example where my-define handles both cases.

#lang racket
(provide (rename-out [my-define define]))
(require (for-syntax syntax/parse))

(define-syntax (my-define stx)
  (syntax-parse stx
    [(_define name:id e:expr)           (syntax/loc stx (define name e))]
    [(_define (name arg ...) body ...)  (syntax/loc stx (define (name arg ...) body ...))]))

Upvotes: 2

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