CODEWITHSUNDEEP
macroslisprackettype-mismatch
Theodor Berza
Theodor Berza

Reputation: 583

Stream time: arity mismatch Error hits in Racket

I wrote this program that uses the macros nota and ping, nota to allow me to define a note easier and ping to compress in only one line of code(the ones starting with ping) what I would do in three lines in the commented section(to send it through the loudspeaker).

The problem is that the two macros appear to not work together and I get the arity mismatch error:

stream-time: arity mismatch; the expected number of arguments does not match the given number expected: 0 given: 2 arguments.: # #

I tried with define and define-syntax and it doesn't work.

#lang racket

(provide (all-defined-out))

(require rsound)

(define-syntax-rule (nota x y)
  (define x
       (network ()
             [sunet <= sine-wave y]
             [out = (+ sunet)])))

(define-syntax-rule (ping y)
    (
     (signal-play y)
     (sleep 0.25)
     (stop)))

(nota E2 82)
(nota F#2 92)
(nota G2 98)
(nota A2 110)

(ping E2)
(ping F#2)
(ping E2)
(ping G2)
(ping E2)
(ping A2)

;(signal-play E2)
;(sleep 0.25)
;(stop)

;(signal-play F#2)
;(sleep 0.25)
;(stop)

;(signal-play G2)
;(sleep 0.25)
;(stop)

;(signal-play A2)
;(sleep 0.25)
;(stop)

Upvotes: 0

Views: 217

Answers (1)

uselpa
uselpa

Reputation: 18917

ping is missing a begin to group the 3 forms:

(define-syntax-rule (ping y)
  (begin
    (signal-play y)
    (sleep 0.25)
    (stop)))

then the macro stepper shows that your code is expanded to

(define E2 (network () [sunet <= sine-wave 82] [out = (+ sunet)]))
(define F#2 (network () [sunet <= sine-wave 92] [out = (+ sunet)]))
(define G2 (network () [sunet <= sine-wave 98] [out = (+ sunet)]))
(define A2 (network () [sunet <= sine-wave 110] [out = (+ sunet)]))
(begin (signal-play E2) (sleep 0.25) (stop))
(begin (signal-play F#2) (sleep 0.25) (stop))
(begin (signal-play E2) (sleep 0.25) (stop))
(begin (signal-play G2) (sleep 0.25) (stop))
(begin (signal-play E2) (sleep 0.25) (stop))
(begin (signal-play A2) (sleep 0.25) (stop))))

Upvotes: 3

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