b8ca2ad9dc
* Moved cur.rkt to main.rkt, which fixes some reader issues * Added sweet-expression tests * Added notes about sweet-expressions to README * Added sweet-exp as dependency to tests
62 lines
1.1 KiB
Racket
62 lines
1.1 KiB
Racket
#lang s-exp "../main.rkt"
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(require "sugar.rkt" "bool.rkt")
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;; TODO: override (all-defined-out) to enable exporting all these
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;; properly.
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(provide Nat z s add1 sub1 plus mult exp square nat-equal? even? odd?)
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(data Nat : Type
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(z : Nat)
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(s : (-> Nat Nat)))
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(define (add1 (n : Nat)) (s n))
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(define (sub1 (n : Nat))
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(match n
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[z z]
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[(s (x : Nat)) x]))
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(define (plus (n1 : Nat) (n2 : Nat))
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(match n1
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[z n2]
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[(s (x : Nat))
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(s (recur x))]))
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(define (mult (m : Nat) (n : Nat))
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(match m
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[z z]
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[(s (x : Nat))
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(plus n (recur x))]))
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(define (exp (m : Nat) (e : Nat))
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(match m
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[z (s z)]
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[(s (x : Nat))
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(mult e (recur x))]))
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(define square (run (exp (s (s z)))))
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(define (zero? (n : Nat))
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(match n
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[z true]
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[(s (n : Nat))
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false]))
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(define (nat-equal? (n : Nat))
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(match n
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[z zero?]
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[(s (n-1 : Nat))
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(lambda (m : Nat)
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(match m
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[z false]
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[(s (m-1 : Nat))
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((recur n-1) m-1)]))]))
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(define (even? (n : Nat))
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(match n
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[z true]
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[(s (n : Nat))
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(not (recur n))]))
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(define (odd? (n : Nat))
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(not (even? n)))
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