syndicate-2017/racket/typed/user-ctors.rkt

131 lines
4.5 KiB
Racket

#lang turnstile
(provide (all-defined-out)
(for-syntax (all-defined-out)))
(require "base-types.rkt")
(require "effects.rkt")
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; User Defined Types, aka Constructors
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(begin-for-syntax
(define-splicing-syntax-class type-constructor-decl
(pattern (~seq #:type-constructor TypeCons:id))
(pattern (~seq) #:attr TypeCons #f))
(struct user-ctor (typed-ctor untyped-ctor)
#:property prop:procedure
(lambda (v stx)
(define transformer (user-ctor-typed-ctor v))
(syntax-parse stx
[(_ e ...)
#`(#,transformer e ...)]))))
(define-syntax (define-constructor* stx)
(syntax-parse stx
#:datum-literals (:)
[(_ (Cons:id : TyCons:id slot:id ...) clause ...)
#'(define-constructor (Cons slot ...)
#:type-constructor TyCons
clause ...)]))
(define-syntax (define-constructor stx)
(syntax-parse stx
[(_ (Cons:id slot:id ...)
ty-cons:type-constructor-decl
(~seq #:with
Alias AliasBody) ...)
#:with TypeCons (or (attribute ty-cons.TypeCons) (format-id stx "~a/t" (syntax-e #'Cons)))
#:with MakeTypeCons (format-id #'TypeCons "make-~a" #'TypeCons)
#:with GetTypeParams (format-id #'TypeCons "get-~a-type-params" #'TypeCons)
#:with TypeConsExpander (format-id #'TypeCons "~~~a" #'TypeCons)
#:with TypeConsExtraInfo (format-id #'TypeCons "~a-extra-info" #'TypeCons)
#:with (StructName Cons- type-tag) (generate-temporaries #'(Cons Cons Cons))
(define arity (stx-length #'(slot ...)))
#`(begin-
(struct- StructName (slot ...) #:reflection-name 'Cons #:transparent)
(define-syntax (TypeConsExtraInfo stx)
(syntax-parse stx
[(_ X (... ...)) #'('type-tag 'MakeTypeCons 'GetTypeParams)]))
(define-type-constructor TypeCons
#:arity = #,arity
#:extra-info 'TypeConsExtraInfo)
(define-syntax (MakeTypeCons stx)
(syntax-parse stx
[(_ t (... ...))
#:fail-unless (= #,arity (stx-length #'(t (... ...)))) "arity mismatch"
#'(TypeCons t (... ...))]))
(define-syntax (GetTypeParams stx)
(syntax-parse stx
[(_ (TypeConsExpander t (... ...)))
#'(t (... ...))]))
(define-syntax Cons
(user-ctor #'Cons- #'StructName))
(define-typed-syntax (Cons- e (... ...))
#:fail-unless (= #,arity (stx-length #'(e (... ...)))) "arity mismatch"
[ e e- ( : τ)] (... ...)
#:fail-unless (all-pure? #'(e- (... ...))) "expressions must be pure"
----------------------
[ (#%app- StructName e- (... ...)) ( : (TypeCons τ (... ...)))])
(define-type-alias Alias AliasBody) ...)]))
(begin-for-syntax
(define-syntax ~constructor-extra-info
(pattern-expander
(syntax-parser
[(_ tag mk get)
#'(_ (_ tag) (_ mk) (_ get))])))
(define-syntax ~constructor-type
(pattern-expander
(syntax-parser
[(_ tag . rst)
#'(~and it
(~fail #:unless (user-defined-type? #'it))
(~parse tag (get-type-tag #'it))
(~Any _ . rst))])))
(define-syntax ~constructor-exp
(pattern-expander
(syntax-parser
[(_ cons . rst)
#'(~and (cons . rst)
(~fail #:unless (ctor-id? #'cons)))])))
(define (inspect t)
(syntax-parse t
[(~constructor-type tag t ...)
(list (syntax-e #'tag) (stx-map type->str #'(t ...)))]))
(define (tags-equal? t1 t2)
(equal? (syntax-e t1) (syntax-e t2)))
(define (user-defined-type? t)
(get-extra-info ((current-type-eval) t)))
(define (get-type-tag t)
(syntax-parse (get-extra-info t)
[(~constructor-extra-info tag _ _)
(syntax-e #'tag)]))
(define (get-type-args t)
(syntax-parse (get-extra-info t)
[(~constructor-extra-info _ _ get)
(define f (syntax-local-value #'get))
(syntax->list (f #`(get #,t)))]))
(define (make-cons-type t args)
(syntax-parse (get-extra-info t)
[(~constructor-extra-info _ mk _)
(define f (syntax-local-value #'mk))
((current-type-eval) (f #`(mk #,@args)))]))
(define (ctor-id? stx)
(and (identifier? stx)
(user-ctor? (syntax-local-value stx (const #f)))))
(define (untyped-ctor stx)
(user-ctor-untyped-ctor (syntax-local-value stx (const #f)))))