41 lines
1.6 KiB
CoffeeScript
41 lines
1.6 KiB
CoffeeScript
chai = require 'chai'
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chai.should()
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expect = chai.expect
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{cons} = require "cons-lists/lists"
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olisp = require '../chapter4/interpreter'
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{read, readForms} = require '../chapter4/reader'
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the_false_value = (cons "false", "boolean")
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lisp = (ast) ->
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ret = undefined
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olisp ast, (i) -> ret = i
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return ret
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describe "Core interpreter #4: Pure Lambda Memory", ->
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it "Understands equality", ->
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expect(lisp read "(eq? 'a 'b)").to.equal(false)
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expect(lisp read "(eq? 'a 'a)").to.equal(true)
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expect(lisp read "(eq? (cons 1 2) (cons 1 2))").to.equal(false)
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expect(lisp read "((lambda (a) (eq? a a)) (cons 1 2))").to.equal(true)
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expect(lisp read "((lambda (a) (eq? a a)) (lambda (x) x))").to.equal(true)
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expect(lisp read "(eq? (lambda (x) 1) (lambda (x y) 2))").to.equal(false)
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it "Understands equivalence", ->
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expect(lisp read "(eqv? '1 '2)").to.equal(false)
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expect(lisp read "(eqv? 1 1)").to.equal(true)
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expect(lisp read "(eqv? 'a 'b)").to.equal(false)
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expect(lisp read "(eqv? 'a 'a)").to.equal(true)
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expect(lisp read "(eqv? (cons 1 2) (cons 1 2))").to.equal(false)
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expect(lisp read "((lambda (a) (eqv? a a)) (cons 1 2))").to.equal(true)
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expect(lisp read "((lambda (a) (eqv? a a)) (lambda (x) x))").to.equal(true)
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expect(lisp read "(eqv? (lambda (x) 1) (lambda (x y) 2))").to.equal(false)
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it "Does special OR (backtracking without side-effect)", ->
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expr1 = "((lambda (x) (or (begin (set! x (+ x 1)) #f) (if (= x 1) \"OK\" \"KO\"))) 1)"
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expect(lisp read expr1).to.equal("OK")
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expr2 = "((lambda (x) (or (begin (set! x (+ x 1)) #f) (if (= x 1) (begin (set! x 3) x) \"KO\"))) 1)"
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expect(lisp read expr2).to.equal(3)
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