106 lines
4.3 KiB
Racket
106 lines
4.3 KiB
Racket
#lang racket/base
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(require
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(for-syntax
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racket/base syntax/parse syntax/parse/experimental/template
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syntax/stx racket/syntax racket/set
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"stx-utils.rkt")
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(for-meta 2 racket/base syntax/parse)
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"typecheck.rkt")
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(require
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(except-in
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"stlc.rkt"
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define-type begin #%app λ
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check-type-error check-type check-type-and-result check-not-type check-equal?))
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(require (prefix-in stlc: (only-in "stlc.rkt" #%app define-type λ begin)))
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(provide (all-from-out "stlc.rkt"))
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(provide
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define-type
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(rename-out
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[stlc:begin begin]
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[app/tc #%app]
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[λ/tc λ]))
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;; define-type ----------------------------------------------------------------
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(define-syntax (define-type stx)
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(syntax-parse stx #:datum-literals (variant)
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[(_ (Tycon:id X ...) (variant (Cons:id τ_fld ...) ...))
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#:with ((x ...) ...) (stx-map generate-temporaries #'((τ_fld ...) ...))
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#:when (Γ (type-env-extend #'([Cons (∀ (X ...) (→ τ_fld ... (Tycon X ...)))] ...)))
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#'(begin ; should be racket begin
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(struct Cons (x ...) #:transparent) ...)]
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[(_ any ...) #'(stlc:define-type any ...)]))
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;; lambda ---------------------------------------------------------------------
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(define-syntax (λ/tc stx)
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(syntax-parse stx #:datum-literals (:)
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;; most of the code from this case, except for the curly? check,
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;; is copied from stlc:λ
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[(_ τs ([x:id : τ] ...) e ... e_result)
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#:when (curly-parens? #'τs)
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;; the with-extended-type-env must be outside the expand/df (instead of
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;; around just the body) bc ow the parameter will get restored to the old
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;; value before the local-expand happens
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#:with (lam xs e+ ... e_result+) (with-extended-type-env #'([x τ] ...)
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(expand/df #'(λ (x ...) e ... e_result)))
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;; manually handle identifiers here
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;; - since Racket has no #%var hook, ids didn't get "expanded" in the previous line
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;; and thus didn't get a type
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;; TODO: can I put this somewhere else where it's more elegant?
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#:with (e++ ... e_result++) (with-extended-type-env #'([x τ] ...)
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(stx-map
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(λ (e) (if (identifier? e) (expand/df e) e))
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#'(e+ ... e_result+)))
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;; manually handle the implicit begin
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#:when (stx-map assert-Unit-type #'(e++ ...))
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#:with τ_body (typeof #'e_result++)
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(⊢ (syntax/loc stx (lam xs e++ ... e_result++)) #'(∀ τs (→ τ ... τ_body)))]
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[(_ any ...) #'(stlc:λ any ...)]))
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; #%app -----------------------------------------------------------------------
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(define-syntax (app/tc stx)
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(syntax-parse stx #:literals (→ void)
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[(_ e_fn τs e_arg ...)
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#:when (curly-parens? #'τs)
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#:with (e_fn+ e_arg+ ...) (stx-map expand/df #'(e_fn e_arg ...))
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#:with (∀ (X ...) (→ τX ...)) (typeof #'e_fn+)
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#:with (→ τ_arg ... τ_res) (apply-forall (typeof #'e_fn+) #'τs)
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#:when (stx-andmap assert-type #'(e_arg+ ...) #'(τ_arg ...))
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(⊢ (syntax/loc stx (#%app e_fn+ e_arg+ ...)) #'τ_res)]
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[(_ any ...) #'(stlc:#%app any ...)]))
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;; testing fns ----------------------------------------------------------------
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;; for now, these are duplicated from stlc.rkt: 2014-08-14
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;; type checking testing: -----------------------------------------------------
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(require rackunit)
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(require (for-syntax rackunit "typecheck.rkt"))
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(provide check-equal?)
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(provide check-type-error check-type check-type-and-result check-not-type)
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(define-syntax (check-type-error stx)
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(syntax-parse stx
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[(_ e)
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#:when (check-exn exn:fail? (λ () (expand/df #'e)))
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#'(void)]))
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(define-syntax (check-type stx)
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(syntax-parse stx #:datum-literals (:)
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[(_ e : τ)
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#:with e+ (expand/df #'e)
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#:when (check-true (assert-type #'e+ #'τ)
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(format "Expected type ~a but got type ~a" #'τ (typeof #'e)))
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#'(void)]))
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(define-syntax (check-not-type stx)
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(syntax-parse stx #:datum-literals (:)
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[(_ e : τ)
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#:with e+ (expand/df #'e)
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#:when (check-false (type=? (typeof #'e+) #'τ)
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(format "Expected type to not be ~a but got type ~a" #'τ (typeof #'e)))
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#'(void)]))
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(define-syntax (check-type-and-result stx)
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(syntax-parse stx #:datum-literals (: =>)
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[(_ e : τ => v)
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#'(begin (check-type e : τ)
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(check-equal? e v))]))
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