abstract-compilation
Simple DSL for defining abstract compilers, making the task not much more verbose than defining interpreters by getting rid of some boilerplates.
Install
raco pkg install abstract-compilation
Example
#lang typed/racket/base
(require abstract-compilation)
(define-type ρ (Immutable-HashTable Symbol Integer))
(define-type Comp (ρ → Integer))
(: ⟦_⟧ : Any → Comp)
(define-compiler ((⟦_⟧ e) ρ)
;; e ::= x | ℤ | (+ e ...) | (- e ...) | (let ([x e]) e)
[(? symbol? x) (intern x)]
[(? exact-integer? n) (intern n)]
[=> `(+ ,es ...)
(for/sum ([f ⟦e⟧s]) (f ρ))
#:recur [(es ...) #:as ⟦e⟧s]]
[=> `(- ,e)
(- (⟦e⟧ ρ))
#:recur e]
[=> `(- ,e₁ ,es ...)
(- (⟦e₁⟧ ρ) (for/sum : Integer ([f ⟦es⟧]) (f ρ)))
#:recur e₁ (es ...)]
[=> `(let ([,(? symbol? x) ,eₓ]) ,e)
(⟦e⟧ (hash-set ρ x (⟦eₓ⟧ ρ)))
#:recur eₓ e])
(define intern : ((U Integer Symbol) → Comp)
(let ([m : (Mutable-HashTable (U Integer Symbol) Comp) (make-hasheq)])
(λ (x)
(define (mk) : Comp
(cond [(integer? x) (λ _ x)]
[else (λ (ρ) (hash-ref ρ x (λ () (error x "unbound"))))]))
(hash-ref! m x mk))))
(define prog '(let ([x (+ 1 2)])
(let ([y (- 1 2 3)])
(+ x y))))
(define ⟦prog⟧ (⟦_⟧ prog))
(⟦prog⟧ (hasheq)) ; ==> -1