WIP on fixing free-variance.

collects/typed-racket/infer/infer-unit.rkt

@@ -581,8 +581,8 @@
 ;; R : Type? - result type into which we will be substituting
 (define/cond-contract (subst-gen C Y R)
   (cset? (listof symbol?) Type? . -> . (or/c #f substitution/c))
-  (define var-hash (free-vars* R))
-  (define idx-hash (free-idxs* R))
+  (define var-hash (free-vars-hash (free-vars* R)))
+  (define idx-hash (free-vars-hash (free-idxs* R)))
   ;; v : Symbol - variable for which to check variance
   ;; h : (Hash Symbol Variance) - hash to check variance in (either var or idx hash)
   ;; variable: Symbol - variable to use instead, if v was a temp var for idx extension

collects/typed-racket/rep/filter-rep.rkt

@@ -21,14 +21,12 @@
 
 (def-filter TypeFilter ([t Type?] [p (listof PathElem?)] [v name-ref/c])
   [#:intern (list (Rep-seq t) (map Rep-seq p) (hash-name v))]
-  [#:frees (combine-frees (map free-vars* (cons t p)))
-           (combine-frees (map free-idxs* (cons t p)))]
+  [#:frees (λ (f) (combine-frees (map f (cons t p))))]
   [#:fold-rhs (*TypeFilter (type-rec-id t) (map pathelem-rec-id p) v)])
 
 (def-filter NotTypeFilter ([t Type?] [p (listof PathElem?)] [v name-ref/c])
   [#:intern (list (Rep-seq t) (map Rep-seq p) (hash-name v))]
-  [#:frees (combine-frees (map free-vars* (cons t p)))
-           (combine-frees (map free-idxs* (cons t p)))]
+  [#:frees (λ (f) (combine-frees (map f (cons t p))))]
   [#:fold-rhs (*NotTypeFilter (type-rec-id t) (map pathelem-rec-id p) v)])
 
 ;; implication
@@ -36,13 +34,11 @@
 
 (def-filter AndFilter ([fs (non-empty-listof Filter/c)])
   [#:fold-rhs (*AndFilter (map filter-rec-id fs))]
-  [#:frees (combine-frees (map free-vars* fs))
-           (combine-frees (map free-idxs* fs))])
+  [#:frees (λ (f) (combine-frees (map f fs)))])
 
 (def-filter OrFilter ([fs (non-empty-listof Filter/c)])
   [#:fold-rhs (*OrFilter (map filter-rec-id fs))]
-  [#:frees (combine-frees (map free-vars* fs))
-           (combine-frees (map free-idxs* fs))])
+  [#:frees (λ (f) (combine-frees (map f fs)))])
 
 (def-filter FilterSet (thn els)
   [#:contract (->i ([t any/c]

collects/typed-racket/rep/free-variance.rkt

@@ -2,7 +2,7 @@
 (require "../utils/utils.rkt" (for-syntax racket/base) (contract-req)) 
 
 (provide Covariant Contravariant Invariant Constant Dotted
-         combine-frees flip-variances without-below unless-in-table
+         combine-frees flip-variances without-below
          fix-bound make-invariant make-constant variance?)
 
 ;; this file contains support for calculating the free variables/indexes of types
@@ -22,6 +22,9 @@
 (define (variance? e)
   (memq e (list Covariant Contravariant Invariant Constant Dotted)))
 
+(struct frees ())
+(struct (ht-frees frees) (table))
+
 ;; frees = HT[Idx,Variance] where Idx is either Symbol or Number
 ;; (listof frees) -> frees
 (define (combine-frees freess)
@@ -33,10 +36,11 @@
       [(eq? v Constant) w]
       [(eq? w Constant) v]
       [else Invariant]))
+  (ht-frees
     (for*/fold ([ht #hasheq()])
-    ([old-ht (in-list freess)]
-     [(sym var) (in-hash old-ht)])
-    (hash-update ht sym (combine-var var) var)))
+      ([old-free (in-list freess)]
+       [(sym var) (in-hash (ht-frees-table old-ht))])
+      (hash-update ht sym (combine-var var) var))))
 
 ;; given a set of free variables, change bound to ...
 ;; (if bound wasn't free, this will add it as Dotted
@@ -44,31 +48,47 @@
 ;;  it as "free" will -- fixes the case where the
 ;;  dotted pre-type base doesn't use the bound).
 (define (fix-bound vs bound)
-  (hash-set vs bound Dotted))
+  (match vs
+    ((ht-frees ht)
+     (ht-frees (hash-set ht bound Dotted)))))
 
 ;; frees -> frees
 (define (flip-variances vs)
-  (for/hasheq ([(k v) (in-hash vs)])
+  (ht-frees
+    (for/hasheq ([(k v) (in-hash (ht-frees-table vs))])
       (values k 
               (cond [(eq? v Covariant) Contravariant]
                     [(eq? v Contravariant) Covariant]
-                  [else v]))))
+                    [else v])))))
 
 (define (make-invariant vs)
-  (for/hasheq ([(k v) (in-hash vs)])
-    (values k Invariant)))
+  (ht-frees
+    (for/hasheq ([(k v) (in-hash (ht-frees-table vs))])
+      (values k Invariant))))
 
 (define (make-constant vs)
-  (for/hasheq ([(k v) (in-hash vs)])
-    (values k Constant)))
+  (ht-frees
+    (for/hasheq ([(k v) (in-hash (ht-frees-table vs))])
+      (values k Constant))))
 
 (define (without-below n frees)
-  (for/hasheq ([(k v) (in-hash frees)]
+  (ht-frees
+    (for/hasheq ([(k v) (in-hash (ht-frees-table frees))]
                  #:when (>= k n))
-    (values k v)))
+      (values k v))))
+
+(define (single-free-var name (variance Covariant))
+  (ht-frees (hasheq name variance)))
+
+(define empty-free-vars 
+  (ht-frees (hasheq)))
+
+(define (free-vars-remove vars name)
+  (ht-frees
+    (hash-remove (ht-frees-table vars) name)))
+
+;; Only valid after full type resolution
+(define (free-vars-hash vars)
+  (ht-frees-table vars))
+
 
-(define-syntax (unless-in-table stx)
-  (syntax-case stx ()
-    [(_ table val . body)
-     (quasisyntax/loc stx
-       (hash-ref table val #,(syntax/loc #'body (lambda () . body))))]))

collects/typed-racket/rep/object-rep.rkt

@@ -8,14 +8,14 @@
 (def-pathelem SyntaxPE () [#:fold-rhs #:base])
 ;; t is always a Name (can't put that into the contract b/c of circularity)
 (def-pathelem StructPE ([t Type?] [idx natural-number/c])
-  [#:frees (free-vars* t) (free-idxs* t)]
+  [#:frees (λ (f) (f t))]
   [#:fold-rhs (*StructPE (type-rec-id t) idx)])
 
 (def-object Empty () [#:fold-rhs #:base])
 
 (def-object Path ([p (listof PathElem?)] [v name-ref/c])
   [#:intern (list (map Rep-seq p) (hash-name v))]
-  [#:frees (combine-frees (map free-vars* p)) (combine-frees (map free-idxs* p))]
+  [#:frees (λ (f) (combine-frees (map f p)))]
   [#:fold-rhs (*Path (map pathelem-rec-id p) v)])
 
 ;; represents no info about the object of this expression
@@ -28,6 +28,6 @@
 (dlo LEmpty () [#:fold-rhs #:base])
 
 (dlo LPath ([p (listof PathElem?)] [idx index/c])
-  [#:frees (combine-frees (map free-vars* p)) (combine-frees (map free-idxs* p))]
+  [#:frees (λ (f) (combine-frees (map f p)))]
   [#:fold-rhs (*LPath (map pathelem-rec-id p) idx)])
 |#

collects/typed-racket/rep/rep-utils.rkt

@@ -58,7 +58,7 @@
   ;; (construction prevents duplicates)
   (define (combiner f flds)
     (syntax-parse flds
-      [() #'#hasheq()]
+      [() #'empty-free-vars]
       [(e) #`(#,f e)]
       [(e ...) #`(combine-frees (list (#,f e) ...))]))
 
@@ -68,8 +68,8 @@
     (pattern (~seq f1:expr f2:expr))
     ;; [#:frees #f] pattern in e.g. def-type means no free vars or idxs.
     (pattern #f
-             #:with f1 #'#hasheq()
-             #:with f2 #'#hasheq())
+             #:with f1 #'empty-free-vars
+             #:with f2 #'empty-free-vars)
     ;; [#:frees (λ (f) ...)] should combine free variables or idxs accordingly
     ;; (given the respective accessor functions)
     (pattern e:expr

collects/typed-racket/rep/type-rep.rkt

@@ -52,7 +52,7 @@
 
 ;; free type variables
 ;; n is a Name
-(def-type F ([n symbol?]) [#:frees (make-immutable-hasheq (list (cons n Covariant))) #hasheq()] [#:fold-rhs #:base])
+(def-type F ([n symbol?]) [#:frees (single-free-var n) empty-free-vars] [#:fold-rhs #:base])
 
 ;; id is an Identifier
 (def-type Name ([id identifier?]) [#:intern (hash-id id)] [#:frees #f] [#:fold-rhs #:base])
@@ -62,47 +62,22 @@
 ;; stx is the syntax of the pair of parens
 (def-type App ([rator Type/c] [rands (listof Type/c)] [stx (or/c #f syntax?)])
   [#:intern (cons (Rep-seq rator) (map Rep-seq rands))]
+  ;;TODO THIS
   [#:frees (λ (f) (combine-frees (map f (cons rator rands))))]
   [#:fold-rhs (*App (type-rec-id rator)
                     (map type-rec-id rands)
                     stx)])
 
-(define (get-variances t num-rands)
-  (match t
-    [(Name: v) (error 'fail)]
-    [(Poly: n scope)
-     (let ([t (free-idxs* scope)])
-       (for/list ([i (in-range n)])
-         (hash-ref t i)))]
-    [(PolyDots: n scope)
-     (let ([t (free-idxs* scope)]
-           [base-count (sub1 n)]
-           [extras (max 0 (- n num-rands))])
-       (append
-        ;; variances of the fixed arguments
-        (for/list ([i (in-range base-count)])
-          (hash-ref t i))
-        ;; variance of the dotted arguments
-        (for/list ([i (in-range extras)])
-          (hash-ref t n))))]))
-
-(define (apply-variance v tbl)
-  (match v
-    [(== Constant) (make-constant tbl)]
-    [(== Covariant) tbl]
-    [(== Invariant) (make-invariant tbl)]
-    [(== Contravariant) (flip-variances tbl)]))
-
 ;; left and right are Types
 (def-type Pair ([left Type/c] [right Type/c]) [#:key 'pair])
 
 ;; dotted list -- after expansion, becomes normal Pair-based list type
 (def-type ListDots ([dty Type/c] [dbound (or/c symbol? natural-number/c)])
   [#:frees (if (symbol? dbound)
-               (hash-remove (free-vars* dty) dbound)
+               (free-vars-remove (free-vars* dty) dbound)
                (free-vars* dty))
            (if (symbol? dbound)
-               (combine-frees (list (make-immutable-hasheq (list (cons dbound Covariant))) (free-idxs* dty)))
+               (combine-frees (list (single-free-var dbound) (free-idxs* dty)))
                (free-idxs* dty))]
   [#:fold-rhs (*ListDots (type-rec-id dty) dbound)])
 
@@ -232,10 +207,10 @@
 
 (def-type ValuesDots ([rs (listof Result?)] [dty Type/c] [dbound (or/c symbol? natural-number/c)])
   [#:frees (if (symbol? dbound)
-               (hash-remove (combine-frees (map free-vars* (cons dty rs))) dbound)
+               (free-vars-remove (combine-frees (map free-vars* (cons dty rs))) dbound)
                (combine-frees (map free-vars* (cons dty rs))))
            (if (symbol? dbound)
-               (combine-frees (cons (make-immutable-hasheq (list (cons dbound Covariant)))
+               (combine-frees (cons (single-free-var dbound) 
                                     (map free-idxs* (cons dty rs))))
                (combine-frees (map free-idxs* (cons dty rs))))]
   [#:fold-rhs (*ValuesDots (map type-rec-id rs) (type-rec-id dty) dbound)])
@@ -256,7 +231,7 @@
                                  dom))
                     (match drest
                       [(cons t (? symbol? bnd))
-                       (list (hash-remove (flip-variances (free-vars* t)) bnd))]
+                       (list (free-vars-remove (flip-variances (free-vars* t)) bnd))]
                       [(cons t _)
                        (list (flip-variances (free-vars* t)))]
                       [_ null])
@@ -268,7 +243,7 @@
                                  dom))
                     (match drest
                       [(cons t (? symbol? bnd))
-                       (list (make-immutable-hasheq (list (cons bnd Contravariant)))
+                       (list (single-free-var bnd Contravariant)
                              (flip-variances (free-idxs* t)))]
                       [(cons t _)
                        (list (flip-variances (free-idxs* t)))]

collects/typed-racket/typecheck/tc-toplevel.rkt

@@ -290,9 +290,12 @@
      provide?
      define/fixup-contract?))
   (do-time "Form splitting done")
+  (printf "before parsing type aliases~n")
   (for-each (compose register-type-alias parse-type-alias) type-aliases)
   ;; Add the struct names to the type table, but not with a type
+  (printf "before adding type names~n")
   (for-each (compose add-type-name! names-of-struct) struct-defs)
+  (printf "after adding type names~n")
   ;; resolve all the type aliases, and error if there are cycles
   (resolve-type-aliases parse-type)
   ;; Parse and register the structure types
@@ -304,19 +307,20 @@
 
   ;; register the bindings of the structs
   (for-each register-parsed-struct-bindings! parsed-structs)
-  (do-time "Starting pass1")
+  (printf "after resolving type aliases~n")
+  (displayln "Starting pass1")
   ;; do pass 1, and collect the defintions
   (define defs (apply append (filter list? (map tc-toplevel/pass1 forms))))
-  (do-time "Finished pass1")
+  (displayln "Finished pass1")
   ;; separate the definitions into structures we'll handle for provides
   (define def-tbl
     (for/fold ([h (make-immutable-free-id-table)])
       ([def (in-list defs)])
       (dict-set h (binding-name def) def)))
   ;; typecheck the expressions and the rhss of defintions
-  (do-time "Starting pass2")
+  (displayln "Starting pass2")
   (for-each tc-toplevel/pass2 forms)
-  (do-time "Finished pass2")
+  (displayln "Finished pass2")
   ;; check that declarations correspond to definitions
   (check-all-registered-types)
   ;; report delayed errors