Evaluation

Import an eval library

Given a file named “main.scm” with:

(import (scheme eval))

When I successfully run scheme main.scm

Then the exit status should be 0.

Evaluate false

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-u8 (if (eval #f (environment)) 65 66))

When I successfully run scheme main.scm

Then the stdout should contain exactly “B”.

Evaluate a number

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-u8 (eval 65 (environment)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “A”.

Evaluate a string

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-string (eval "foo" (environment)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “foo”.

Use an environment

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-u8 (eval 65 (environment '(scheme base))))

When I successfully run scheme main.scm

Then the stdout should contain exactly “A”.

Use two environments

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-u8 (eval 65 (environment '(scheme base) '(scheme write))))

When I successfully run scheme main.scm

Then the stdout should contain exactly “A”.

Use an interaction environment

Given a file named “main.scm” with:

(import (scheme base) (scheme eval) (scheme repl))

(write-u8 (eval 65 (interaction-environment)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “A”.

Use a + procedure

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-u8 (eval '(+ 60 5) (environment '(scheme base))))

When I successfully run scheme main.scm

Then the stdout should contain exactly “A”.

Use a display procedure

Given a file named “main.scm” with:

(import (scheme base) (scheme eval) (scheme write))

(eval '(display "foo") (environment '(scheme write)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “foo”.

Use a define syntax with a variable

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(eval
  '(begin
    (define x 65)
    (write-u8 x))
  (environment '(scheme base)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “A”.

Use a define syntax with a procedure

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(eval
  '(begin
    (define (f x)
      (+ x 65))
    (write-u8 (f 1)))
  (environment '(scheme base)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “B”.

Use an if syntax

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(eval '(write-u8 (if <value> 65 66)) (environment '(scheme base)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “<output>”.

Examples

value	output
#f	B
#t	A

Primitives

Use a $$begin primitive

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-u8 (eval '($$begin 42 65) (environment)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “A”.

Use a $$if primitive with a false condition

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-u8 (eval '($$if #f 65 66) (environment)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “B”.

Use a $$if primitive with a true condition

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-u8 (eval '($$if #t 65 66) (environment)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “A”.

Use a $$lambda primitive with no argument

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-u8 (eval '(($$lambda () 65)) (environment)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “A”.

Use a $$lambda primitive with an argument

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-u8 (eval '(($$lambda (x) x) 65) (environment)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “A”.

Use a $$set! primitive

Given a file named “main.scm” with:

(import (scheme base) (scheme eval))

(write-u8 (eval '($$begin ($$set! x 65) x) (environment)))

When I successfully run scheme main.scm

Then the stdout should contain exactly “A”.