@ -205,7 +205,7 @@ Define a function that behaves differently depending on how many arguments are s
(define-macro id (syntax other-id))
(define-macro id (lambda (arg-id) result-expr ...+))
(define-macro id transformer-id)
(define-macro id (syntax result-expr))
(define-macro id syntax-object)
(define-macro (id pat-arg ...) expr ...+)
]]
Create a macro using one of the subforms above, which are explained below:
@ -274,8 +274,7 @@ bad-listener
@specsubform[#:literals (define-macro)
(define-macro (id pat-arg ...) result-expr ...+)]{
If the first argument is a @seclink["stx-patterns" #:doc '(lib "scribblings/reference/reference.scrbl")]
{syntax pattern} starting with @racket[id], then create a syntax transformer for this pattern using @racket[result-expr ...] as the return value. As usual, @racket[result-expr ...] needs to return a @seclink["stx-obj" #:doc '(lib "scribblings/guide/guide.scrbl")]{syntax object} or you'll get an error.
If the first argument is a @seclink["stx-patterns" #:doc '(lib "scribblings/reference/reference.scrbl")]{syntax pattern} starting with @racket[id], then create a syntax transformer for this pattern using @racket[result-expr ...] as the return value. As usual, @racket[result-expr ...] needs to return a @seclink["stx-obj" #:doc '(lib "scribblings/guide/guide.scrbl")]{syntax object} or you'll get an error.
The syntax-pattern notation is the same as @racket[syntax-case], with one key difference. If a @racket[pat-arg] has a @tt{CAPITALIZED-NAME}, it's treated as a named wildcard (meaning, it will match any expression in that position, and can be subsequently referred to by that name). Otherwise, @racket[pat-arg] is treated as a literal (meaning, it will only match the same expression).