letrec-syntax

Define a recursive local macro

Given a file named “main.scm” with:

(import (scheme base))

(letrec-syntax
  ((foo
    (syntax-rules ()
      ((_ x)
        x)
      ((_ x y)
        (foo y)))))
  (write-u8 (foo 65 66)))

When I successfully run stak main.scm

Then the stdout should contain exactly “B”.

Define a mutually recursive local macro

Given a file named “main.scm” with:

(import (scheme base))

(letrec-syntax (
  (foo
    (syntax-rules ()
      ((_ x)
        x)
      ((_ x ... y)
        (bar x ...))))
  (bar
    (syntax-rules ()
      ((_ x)
        x)
      ((_ x ... y)
        (foo x ...)))))
  (write-u8 (foo 65 66 67)))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Put a sequence in a body of letrec-syntax

Given a file named “main.scm” with:

(import (scheme base))

(letrec-syntax ()
  (write-u8 65)
  (write-u8 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “AB”.