fear_of_macros.rkt

fear_of_macros.rkt

#lang racket
(define-syntax foo
    (lambda (stx)
      (syntax "I am foo")))

(define-syntax (also-foo stx)
    (syntax "I am also foo"))

(define-syntax (quoted-foo stx)
    #'"I am also foo, using #' instead of syntax")

(define-syntax (say-hi stx)
    #'(displayln "hi"))

(define-syntax (show-me stx)
    (print stx)
    #'(void))

(define stx #'(if x (list "true") #f))
(syntax-source stx)
(syntax-line stx)
(syntax->datum stx)
(syntax-e stx) ;; one level down
(syntax->list stx)

(define-syntax (reverse-me stx)
    (datum->syntax stx (reverse (cdr (syntax->datum stx)))))

(require (for-syntax racket/match))
(define-syntax (our-if-using-match-v2 stx)
    (match (syntax->list stx)
      [(list _ condition true-expr false-expr)
       (datum->syntax stx `(cond [,condition ,true-expr]
                                 [else ,false-expr]))]))

(define-syntax (our-if-using-syntax-case stx)
    (syntax-case stx ()
      [(_ condition true-expr false-expr)
       #'(cond [condition true-expr]
               [else false-expr])]))

(define-syntax-rule (our-if-using-syntax-rule condition true-expr false-expr)
    (cond [condition true-expr]
          [else false-expr]))