From a82a833b43e9052a409aa736c0e971140464ec8c Mon Sep 17 00:00:00 2001
From: Stephen Chang <stchang@ccs.neu.edu>
Date: Tue, 12 Jan 2016 15:29:56 -0500
Subject: [PATCH] add stlc+effect.rkt

---
 tapl/stlc+effect.rkt             |  71 ++++++++++
 tapl/tests/stlc+effect-tests.rkt | 236 +++++++++++++++++++++++++++++++
 2 files changed, 307 insertions(+)
 create mode 100644 tapl/stlc+effect.rkt
 create mode 100644 tapl/tests/stlc+effect-tests.rkt

diff --git a/tapl/stlc+effect.rkt b/tapl/stlc+effect.rkt
new file mode 100644
index 0000000..80072ba
--- /dev/null
+++ b/tapl/stlc+effect.rkt
@@ -0,0 +1,71 @@
+#lang s-exp "typecheck.rkt"
+(extends "stlc+box.rkt" #:except ref deref := #%app λ)
+
+;; Simply-Typed Lambda Calculus, plus mutable references
+;; Types:
+;; - types from stlc+cons.rkt
+;; - Ref constructor
+;; Terms:
+;; - terms from stlc+cons.rkt
+;; - ref deref :=
+
+(begin-for-syntax 
+  (define (add-news e locs) (syntax-property e 'new locs))
+  (define (add-assigns e locs) (syntax-property e 'assign locs))
+  (define (add-derefs e locs) (syntax-property e 'deref locs))
+  (define (add-effects e new-locs assign-locs deref-locs)
+    (add-derefs
+     (add-assigns
+      (add-news e new-locs)
+      assign-locs)
+     deref-locs))
+     
+  (define (get-effects e tag [vs '()])
+    (syntax-property (local-expand (if (null? vs) e #`(stlc+box:λ #,vs #,e)) 'expression null) tag))
+  (define (get-new-effects e [vs '()]) (get-effects e 'new vs))
+  (define (get-assign-effects e [vs '()]) (get-effects e 'assign vs))
+  (define (get-deref-effects e [vs '()]) (get-effects e 'deref vs))
+
+  (define (print-effects e)
+    (printf "expr ~a\n" (syntax->datum e))
+    (define e+ (local-expand e 'expression null))
+    (printf "new locs: ~a\n" (syntax-property e+ 'new))
+    (printf "deref locs: ~a\n" (syntax-property e+ 'deref))
+    (printf "assign locs: ~a\n" (syntax-property e+ 'assign)))
+  
+  (define (loc-union locs1 locs2)
+    (cond
+      [(not locs1) locs2]
+      [(not locs2) locs1]
+      [else (set-union locs1 locs2)])))
+
+
+(define-typed-syntax #%app
+  [(_ efn e ...)
+   #:with [efn- τfn] (infer+erase #'efn)
+   (let ([φ-news (stx-map get-new-effects #'(τfn efn e ...))]
+         [φ-assigns (stx-map get-assign-effects #'(τfn efn e ...))]
+         [φ-derefs (stx-map get-deref-effects #'(τfn efn e ...))])
+     (add-effects #'(stlc+box:#%app efn e ...)
+                  (foldl loc-union (set) φ-news)
+                  (foldl loc-union (set) φ-assigns)
+                  (foldl loc-union (set) φ-derefs)))])
+(define-typed-syntax λ
+  [(_ bvs:type-ctx e)
+   #:with (xs- e- τ_res) (infer/ctx+erase #'bvs #'e)
+   (let ([φ-news (get-new-effects #'e-)]
+         [φ-assigns (get-assign-effects #'e-)]
+         [φ-derefs (get-deref-effects #'e-)])
+     (assign-type
+      #'(λ xs- e-)
+      (add-effects #'(→ bvs.type ... τ_res) φ-news φ-assigns φ-derefs)))])
+
+(define-typed-syntax ref
+  [(_ e)
+   (syntax-property #'(stlc+box:ref e) 'new (set (syntax-position stx)))])
+(define-typed-syntax deref
+  [(_ e)
+   (syntax-property #'(stlc+box:deref e) 'deref (set (syntax-position stx)))])
+(define-typed-syntax :=
+  [(_ e_ref e)
+   (syntax-property #'(stlc+box::= e_ref e) 'assign (set (syntax-position stx)))])
\ No newline at end of file
diff --git a/tapl/tests/stlc+effect-tests.rkt b/tapl/tests/stlc+effect-tests.rkt
new file mode 100644
index 0000000..5ee227e
--- /dev/null
+++ b/tapl/tests/stlc+effect-tests.rkt
@@ -0,0 +1,236 @@
+#lang s-exp "../stlc+effect.rkt"
+(require "rackunit-typechecking.rkt")
+
+(define x (ref 10))
+(check-type x : (Ref Int))
+(check-type (deref x) : Int ⇒ 10)
+(check-type (:= x 20) : Unit) ; x still 10 because check-type does not evaluate
+(check-type (begin (:= x 20) (deref x)) : Int ⇒ 20)
+(check-type x : (Ref Int))
+(check-type (deref (ref 20)) : Int ⇒ 20)
+(check-type (deref x) : Int ⇒ 20)
+
+(check-type ((λ ([b : (Ref Int)]) (deref b)) (ref 10)) : Int ⇒ 10)
+(check-type ((λ ([x : Int]) x) ((λ ([b : (Ref Int)]) (deref b)) (ref 10))) : Int ⇒ 10)
+(check-type ((λ ([b : (Ref Int)]) (begin (begin (:= b 20) (deref b)))) (ref 10)) : Int ⇒ 20)
+
+;; Ref err msgs
+; wrong arity
+(typecheck-fail
+ (λ ([lst : (Ref Int Int)]) lst)
+ #:with-msg
+ "Improper usage of type constructor Ref: \\(Ref Int Int), expected pattern \\(Ref τ)")
+(typecheck-fail
+ (λ ([lst : (Ref)]) lst)
+ #:with-msg
+ "Improper usage of type constructor Ref: \\(Ref), expected pattern \\(Ref τ)")
+(typecheck-fail
+ (deref 1)
+ #:with-msg
+ "Expected type of expression.+to match pattern \\(Ref τ), got: Int")
+(typecheck-fail
+ (:= 1 1)
+ #:with-msg
+ "Expected type of expression.+to match pattern \\(Ref τ), got: Int")
+
+;; previous tests: ------------------------------------------------------------
+(typecheck-fail (cons 1 2))
+;(typecheck-fail (cons 1 nil)) ; works now
+(check-type (cons 1 nil) : (List Int))
+(check-type (cons 1 (nil {Int})) : (List Int))
+(typecheck-fail nil)
+(typecheck-fail (nil Int))
+(typecheck-fail (nil (Int)))
+; passes bc ⇒-rhs is only used for its runtime value
+(check-type (nil {Int}) : (List Int) ⇒ (nil {Bool}))
+(check-not-type (nil {Bool}) : (List Int))
+(check-type (nil {Bool}) : (List Bool))
+(check-type (nil {(→ Int Int)}) : (List (→ Int Int)))
+(define fn-lst (cons (λ ([x : Int]) (+ 10 x)) (nil {(→ Int Int)})))
+(check-type fn-lst : (List (→ Int Int)))
+(check-type (isnil fn-lst) : Bool ⇒ #f)
+(typecheck-fail (isnil (head fn-lst))) ; head lst is not List
+(check-type (isnil (tail fn-lst)) : Bool ⇒ #t)
+(check-type (head fn-lst) : (→ Int Int))
+(check-type ((head fn-lst) 25) : Int ⇒ 35)
+(check-type (tail fn-lst) : (List (→ Int Int)) ⇒ (nil {(→ Int Int)}))
+
+;; previous tests: ------------------------------------------------------------
+;; define-type-alias
+(define-type-alias Integer Int)
+(define-type-alias ArithBinOp (→ Int Int Int))
+
+(check-type ((λ ([x : Int]) (+ x 2)) 3) : Integer)
+(check-type ((λ ([x : Integer]) (+ x 2)) 3) : Int)
+(check-type ((λ ([x : Integer]) (+ x 2)) 3) : Integer)
+(check-type + : ArithBinOp)
+(check-type (λ ([f : ArithBinOp]) (f 1 2)) : (→ (→ Int Int Int) Int))
+
+(check-type "Stephen" : String)
+(check-type (tup [name = "Stephen"] [phone = 781] [male? = #t]) :
+            (× [name : String] [phone : Int] [male? : Bool]))
+(check-type (proj (tup [name = "Stephen"] [phone = 781] [male? = #t]) name)
+            : String ⇒ "Stephen")
+(check-type (proj (tup [name = "Stephen"] [phone = 781] [male? = #t]) name)
+            : String ⇒ "Stephen")
+(check-type (proj (tup [name = "Stephen"] [phone = 781] [male? = #t]) phone)
+            : Int ⇒ 781)
+(check-type (proj (tup [name = "Stephen"] [phone = 781] [male? = #t]) male?)
+            : Bool ⇒ #t)
+(check-not-type (tup [name = "Stephen"] [phone = 781] [male? = #t]) :
+                (× [my-name : String] [phone : Int] [male? : Bool]))
+(check-not-type (tup [name = "Stephen"] [phone = 781] [male? = #t]) :
+                (× [name : String] [my-phone : Int] [male? : Bool]))
+(check-not-type (tup [name = "Stephen"] [phone = 781] [male? = #t]) :
+                (× [name : String] [phone : Int] [is-male? : Bool]))
+
+
+(check-type (var coffee = (void) as (∨ [coffee : Unit])) : (∨ [coffee : Unit]))
+(check-not-type (var coffee = (void) as (∨ [coffee : Unit])) : (∨ [coffee : Unit] [tea : Unit]))
+(typecheck-fail ((λ ([x : (∨ [coffee : Unit] [tea : Unit])]) x)
+                 (var coffee = (void) as (∨ [coffee : Unit]))))
+(check-type (var coffee = (void) as (∨ [coffee : Unit] [tea : Unit]))
+            : (∨ [coffee : Unit] [tea : Unit]))
+(check-type (var coffee = (void) as (∨ [coffee : Unit] [tea : Unit] [coke : Unit]))
+            : (∨ [coffee : Unit] [tea : Unit] [coke : Unit]))
+
+(typecheck-fail
+ (case (var coffee = (void) as (∨ [coffee : Unit] [tea : Unit]))
+   [coffee x => 1])) ; not enough clauses
+(typecheck-fail
+ (case (var coffee = (void) as (∨ [coffee : Unit] [tea : Unit]))
+   [coffee x => 1]
+   [teaaaaaa x => 2])) ; wrong clause
+(typecheck-fail
+ (case (var coffee = (void) as (∨ [coffee : Unit] [tea : Unit]))
+   [coffee x => 1]
+   [tea x => 2]
+   [coke x => 3])) ; too many clauses
+(typecheck-fail
+ (case (var coffee = (void) as (∨ [coffee : Unit] [tea : Unit]))
+   [coffee x => "1"]
+   [tea x => 2])) ; mismatched branch types
+(check-type
+ (case (var coffee = 1 as (∨ [coffee : Int] [tea : Unit]))
+   [coffee x => x]
+   [tea x => 2]) : Int ⇒ 1)
+(define-type-alias Drink (∨ [coffee : Int] [tea : Unit] [coke : Bool]))
+(check-type ((λ ([x : Int]) (+ x x)) 10) : Int ⇒ 20)
+(check-type (λ ([x : Int]) (+ (+ x x) (+ x x))) : (→ Int Int))
+(check-type
+ (case ((λ ([d : Drink]) d)
+        (var coffee = 1 as (∨ [coffee : Int] [tea : Unit] [coke : Bool])))
+   [coffee x => (+ (+ x x) (+ x x))]
+   [tea x => 2]
+   [coke y => 3])
+ : Int ⇒ 4)
+
+(check-type
+ (case ((λ ([d : Drink]) d) (var coffee = 1 as Drink))
+   [coffee x => (+ (+ x x) (+ x x))]
+   [tea x => 2]
+   [coke y => 3])
+ : Int ⇒ 4)
+
+;; previous tests: ------------------------------------------------------------
+;; tests for tuples -----------------------------------------------------------
+; fail bc tuple changed syntax
+;(check-type (tup 1 2 3) : (× Int Int Int))
+;(check-type (tup 1 "1" #f +) : (× Int String Bool (→ Int Int Int)))
+;(check-not-type (tup 1 "1" #f +) : (× Unit String Bool (→ Int Int Int)))
+;(check-not-type (tup 1 "1" #f +) : (× Int Unit Bool (→ Int Int Int)))
+;(check-not-type (tup 1 "1" #f +) : (× Int String Unit (→ Int Int Int)))
+;(check-not-type (tup 1 "1" #f +) : (× Int String Bool (→ Int Int Unit)))
+;
+;(check-type (proj (tup 1 "2" #f) 0) : Int ⇒ 1)
+;(check-type (proj (tup 1 "2" #f) 1) : String ⇒ "2")
+;(check-type (proj (tup 1 "2" #f) 2) : Bool ⇒ #f)
+;(typecheck-fail (proj (tup 1 "2" #f) 3)) ; index too large
+;(typecheck-fail (proj 1 2)) ; not tuple
+
+;; ext-stlc.rkt tests ---------------------------------------------------------
+;; should still pass
+
+;; new literals and base types
+(check-type "one" : String) ; literal now supported
+(check-type #f : Bool) ; literal now supported
+
+(check-type (λ ([x : Bool]) x) : (→ Bool Bool)) ; Bool is now valid type
+
+;; Unit
+(check-type (void) : Unit)
+(check-type void : (→ Unit))
+(typecheck-fail ((λ ([x : Unit]) x) 2))
+(typecheck-fail ((λ ([x : Unit])) void))
+(check-type ((λ ([x : Unit]) x) (void)) : Unit)
+
+;; begin
+(typecheck-fail (begin))
+(check-type (begin 1) : Int)
+(typecheck-fail (begin 1 2 3))
+(check-type (begin (void) 1) : Int ⇒ 1)
+
+;;ascription
+(typecheck-fail (ann 1 : Bool))
+(check-type (ann 1 : Int) : Int ⇒ 1)
+(check-type ((λ ([x : Int]) (ann x : Int)) 10) : Int ⇒ 10)
+
+; let
+(check-type (let () (+ 1 1)) : Int ⇒ 2)
+(check-type (let ([x 10]) (+ 1 2)) : Int)
+(typecheck-fail (let ([x #f]) (+ x 1)))
+(check-type (let ([x 10] [y 20]) ((λ ([z : Int] [a : Int]) (+ a z)) x y)) : Int ⇒ 30)
+(typecheck-fail (let ([x 10] [y (+ x 1)]) (+ x y))) ; unbound identifier
+
+(check-type (let* ([x 10] [y (+ x 1)]) (+ x y)) : Int ⇒ 21)
+(typecheck-fail (let* ([x #t] [y (+ x 1)]) 1))
+
+; letrec
+(typecheck-fail (letrec ([(x : Int) #f] [(y : Int) 1]) y))
+(typecheck-fail (letrec ([(y : Int) 1] [(x : Int) #f]) x))
+
+(check-type (letrec ([(x : Int) 1] [(y : Int) (+ x 1)]) (+ x y)) : Int ⇒ 3)
+
+;; recursive
+(check-type
+ (letrec ([(countdown : (→ Int String))
+           (λ ([i : Int])
+             (if (= i 0)
+                 "liftoff"
+                 (countdown (- i 1))))])
+   (countdown 10)) : String ⇒ "liftoff")
+
+;; mutually recursive
+(check-type
+ (letrec ([(is-even? : (→ Int Bool))
+           (λ ([n : Int])
+             (or (zero? n)
+                 (is-odd? (sub1 n))))]
+          [(is-odd? : (→ Int Bool))
+           (λ ([n : Int])
+             (and (not (zero? n))
+                  (is-even? (sub1 n))))])
+   (is-odd? 11)) : Bool ⇒ #t)
+
+;; tests from stlc+lit-tests.rkt --------------------------
+; most should pass, some failing may now pass due to added types/forms
+(check-type 1 : Int)
+;(check-not-type 1 : (Int → Int))
+;(typecheck-fail "one") ; literal now supported
+;(typecheck-fail #f) ; literal now supported
+(check-type (λ ([x : Int] [y : Int]) x) : (→ Int Int Int))
+(check-not-type (λ ([x : Int]) x) : Int)
+(check-type (λ ([x : Int]) x) : (→ Int Int))
+(check-type (λ ([f : (→ Int Int)]) 1) : (→ (→ Int Int) Int))
+(check-type ((λ ([x : Int]) x) 1) : Int ⇒ 1)
+(typecheck-fail ((λ ([x : Bool]) x) 1)) ; Bool now valid type, but arg has wrong type
+;(typecheck-fail (λ ([x : Bool]) x)) ; Bool is now valid type
+(typecheck-fail (λ ([f : Int]) (f 1 2))) ; applying f with non-fn type
+(check-type (λ ([f : (→ Int Int Int)] [x : Int] [y : Int]) (f x y))
+            : (→ (→ Int Int Int) Int Int Int))
+(check-type ((λ ([f : (→ Int Int Int)] [x : Int] [y : Int]) (f x y)) + 1 2) : Int ⇒ 3)
+(typecheck-fail (+ 1 (λ ([x : Int]) x))) ; adding non-Int
+(typecheck-fail (λ ([x : (→ Int Int)]) (+ x x))) ; x should be Int
+(typecheck-fail ((λ ([x : Int] [y : Int]) y) 1)) ; wrong number of args
+(check-type ((λ ([x : Int]) (+ x x)) 10) : Int ⇒ 20)
+