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Type cases for subtracting 1 from Int>1 producing PosInt #883

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ede5aad
numeric-tower: Index>1, Fixnum>1, Int>1
AlexKnauth Nov 16, 2019
3473742
sub1: add cases for Byte>1, Index>1, Fixnum>1, Int>1
AlexKnauth Nov 16, 2019
9798e4b
fx-: add cases for Byte>1, Index>1, Int>1
AlexKnauth Nov 16, 2019
4ff0858
test sub1 on Int>1 returns PosInt
AlexKnauth Nov 16, 2019
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11 changes: 11 additions & 0 deletions typed-racket-lib/typed-racket/base-env/base-env-numeric.rkt
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Original file line number Diff line number Diff line change
Expand Up @@ -134,6 +134,9 @@
(fx-from-cases
(-> -Int -Zero -Fixnum : -true-propset : (-arg-path 0))
(-One -One . -> . -Zero)
(-Byte>1 -One . -> . -PosByte)
(-Index>1 -One . -> . -PosIndex)
(-Int>1 -One . -> . -PosFixnum)
(-PosByte -One . -> . -Byte)
(-PosIndex -One . -> . -Index)
(-PosInt -One . -> . -NonNegFixnum)
Expand Down Expand Up @@ -1105,6 +1108,10 @@

(-> N -Zero N : -true-propset : (-arg-path 0))
(-> -One -One -Zero)
(-> -Byte>1 -One -PosByte)
(-> -Index>1 -One -PosIndex)
(-> -Fixnum>1 -One -PosFixnum)
(-> -Int>1 -One -PosInt)
(-> -PosByte -One -Byte)
(-> -PosIndex -One -Index)
(-> -PosFixnum -One -NonNegFixnum)
Expand Down Expand Up @@ -1291,6 +1298,10 @@

[sub1 (from-cases
(-> -One -Zero)
(-> -Byte>1 -PosByte)
(-> -Index>1 -PosIndex)
(-> -Fixnum>1 -PosFixnum)
(-> -Int>1 -Pos)
(-> -PosByte -Byte)
(-> -PosIndex -Index)
(-> -Index -Fixnum)
Expand Down
22 changes: 15 additions & 7 deletions typed-racket-lib/typed-racket/types/numeric-tower.rkt
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Expand Up @@ -10,9 +10,9 @@
(for-template racket/base racket/contract/base (types numeric-predicates)))

(provide portable-fixnum? portable-index?
-Zero -One -PosByte -Byte -PosIndex -Index
-PosFixnum -NonNegFixnum -NegFixnum -NonPosFixnum -Fixnum
-PosInt -Nat -NegInt -NonPosInt -Int
-Zero -One -Byte>1 -PosByte -Byte -Index>1 -PosIndex -Index
-Fixnum>1 -PosFixnum -NonNegFixnum -NegFixnum -NonPosFixnum -Fixnum
-Int>1 -PosInt -Nat -NegInt -NonPosInt -Int
-PosRat -NonNegRat -NegRat -NonPosRat -Rat
-FlonumPosZero -FlonumNegZero -FlonumZero -FlonumNan
-PosFlonum -NonNegFlonum -NegFlonum -NonPosFlonum -Flonum
Expand Down Expand Up @@ -46,15 +46,18 @@
(define/decl -PosByte (Un -One -Byte>1))
(define/decl -Byte (Un -Zero -PosByte))

(define/decl -PosIndex (Un -One -Byte>1 -PosIndexNotByte))
(define/decl -Index>1 (Un -Byte>1 -PosIndexNotByte))
(define/decl -PosIndex (Un -One -Index>1))
(define/decl -Index (Un -Zero -PosIndex))

(define/decl -Fixnum>1 (Un -PosFixnumNotIndex -Index>1))
(define/decl -PosFixnum (Un -PosFixnumNotIndex -PosIndex))
(define/decl -NonNegFixnum (Un -PosFixnum -Zero))

(define/decl -NonPosFixnum (Un -NegFixnum -Zero))
(define/decl -Fixnum (Un -NegFixnum -Zero -PosFixnum))

(define/decl -Int>1 (Un -PosIntNotFixnum -Fixnum>1))
(define/decl -PosInt (Un -PosIntNotFixnum -PosFixnum))
(define/decl -NonNegInt (Un -PosInt -Zero))
(define/decl -Nat -NonNegInt)
Expand Down Expand Up @@ -132,6 +135,7 @@
(BaseUnion-nbits -Byte) (cons 0 255)
(BaseUnion-nbits -PosByte) (cons 1 255)
(Base-bits -Byte>1) (cons 2 255)
(BaseUnion-nbits -Int>1) (cons 2 #f)
(BaseUnion-nbits -PosInt) (cons 1 #f)
(BaseUnion-nbits -Nat) (cons 0 #f)
(BaseUnion-nbits -NonPosInt) (cons #f 0)
Expand All @@ -158,12 +162,15 @@
(BaseUnion-nbits -Byte) (cons 0 255)
(BaseUnion-nbits -PosByte) (cons 1 255)
(Base-bits -Byte>1) (cons 2 255)
(BaseUnion-nbits -Int>1) (cons 2 #f)
(BaseUnion-nbits -PosInt) (cons 1 #f)
(BaseUnion-nbits -Nat) (cons 0 #f)
(BaseUnion-nbits -NonPosInt) (cons #f 0)
(BaseUnion-nbits -NegInt) (cons #f -1)
(BaseUnion-nbits -Index) (cons 0 #f)
(BaseUnion-nbits -Index>1) (cons 2 #f)
(BaseUnion-nbits -PosIndex) (cons 1 #f)
(BaseUnion-nbits -Fixnum>1) (cons 2 #f)
(BaseUnion-nbits -PosFixnum) (cons 1 #f)
(BaseUnion-nbits -NonNegFixnum) (cons 0 #f)
(BaseUnion-nbits -NonPosFixnum) (cons #f 0)
Expand All @@ -179,9 +186,10 @@

(define all-bounded-int-types
;; relies on numeric bits being eq?
(for/hasheq ([t (in-list (list -Zero -One -PosByte -Byte>1 -Byte -PosIndex -Index
-PosFixnum -NonNegFixnum -NegFixnum -NonPosFixnum
-PosInt -Nat -NegInt -NonPosInt))])
(for/hasheq ([t (in-list (list -Zero -One -PosByte -Byte>1 -Byte
-Index>1 -PosIndex -Index
-Fixnum>1 -PosFixnum -NonNegFixnum -NegFixnum -NonPosFixnum
-Int>1 -PosInt -Nat -NegInt -NonPosInt))])
(values (if (BaseUnion? t)
(BaseUnion-nbits t)
(Base-bits t))
Expand Down
13 changes: 13 additions & 0 deletions typed-racket-test/succeed/sub1-int-gt-1.rkt
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@@ -0,0 +1,13 @@
#lang typed/racket

;; From this stack overflow question by Lyu Yao Ting:
;; Type mismatch issue of sub1
;; https://stackoverflow.com/questions/58887937/type-mismatch-issue-of-sub1

(define-predicate one? One)
(: pick1 (-> Positive-Integer (Listof Any) Any))
(define pick1
(λ (n lat)
(cond [(one? n) (car lat)]
[else (pick1 (sub1 n)
(cdr lat))])))