33 lines
1.1 KiB
Racket
33 lines
1.1 KiB
Racket
#lang turnstile/lang
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(define-type-constructor → #:arity >= 1
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#:arg-variances (λ (stx)
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(syntax-parse stx
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[(_ τ_in ... τ_out)
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(append
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(make-list (stx-length #'[τ_in ...]) contravariant)
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(list covariant))])))
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(define-typed-syntax λ #:datum-literals (:)
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[(_ ([x:id : τ_in:type] ...) e) ≫
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[[x ≫ x- : τ_in.norm] ... ⊢ e ≫ e- ⇒ τ_out]
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-------
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[⊢ (λ- (x- ...) e-) ⇒ (→ τ_in.norm ... τ_out)]]
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[(_ (x:id ...) e) ⇐ (~→ τ_in ... τ_out) ≫
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[[x ≫ x- : τ_in] ... ⊢ e ≫ e- ⇐ τ_out]
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---------
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[⊢ (λ- (x- ...) e-)]])
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(define-typed-syntax (#%app e_fn e_arg ...) ≫
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[⊢ e_fn ≫ e_fn- ⇒ (~→ τ_in ... τ_out)]
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#:fail-unless (stx-length=? #'[τ_in ...] #'[e_arg ...])
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(num-args-fail-msg #'e_fn #'[τ_in ...] #'[e_arg ...])
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[⊢ e_arg ≫ e_arg- ⇐ τ_in] ...
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--------
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[⊢ (#%app- e_fn- e_arg- ...) ⇒ τ_out])
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(define-typed-syntax (ann e (~datum :) τ:type) ≫
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[⊢ e ≫ e- ⇐ τ.norm]
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--------
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[⊢ e- ⇒ τ.norm])
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