scribble-enhanced/graph-lib/graph/map.rkt
2016-03-22 22:59:20 +01:00

150 lines
4.7 KiB
Racket

#lang typed/racket
(require (for-syntax racket/syntax
racket/function
syntax/parse
(submod "../lib/low.rkt" untyped))
"../lib/low.rkt"
"get.lp2.rkt"
"../type-expander/type-expander.lp2.rkt")
(provide car!
cdr!
map:
compose-maps)
(module+ private-tests
(provide λdeep-map
deep-map
deep-map-auto))
(module m typed/racket
(provide car! cdr!)
(: car! ( (A) ( (U (Listof A) (Pairof A Any)) A)))
(define (car! x) (if (pair? x)
(car x)
(car x)))
(: cdr! ( (A) (case→ ( (Listof A) (Listof A))
( (Pairof Any A) A))))
(define (cdr! x) (cdr x)))
(require 'm)
(define-syntax (dbg stx)
(syntax-parse stx
[(_ (~optional (~and norun #:norun)) code)
(if (attribute norun)
#'(ann 'code Any)
#'code)]))
(begin-for-syntax
(define-syntax-class >0 (pattern :exact-positive-integer)))
(begin-for-syntax
(define-syntax-class ≥0 (pattern :exact-nonnegative-integer)))
(define-type-expander (Deep-Listof stx)
(syntax-parse stx
[(_ 0 T)
#'T]
[(_ d:>0 T)
#`(Listof (Deep-Listof #,(sub1 (syntax-e #'d)) T))]))
(define-syntax (λdeep-map stx)
(syntax-parse stx
[(_ {∀-type:id } A:expr B:expr 0)
#'(ann (λ (f x) (f x))
( (∀-type )
( ( A B) A B)
;; Use the type below to allow identity functions, but it's more
;; heavy on the typechecker
#;(case→ ( ( A B) A B)
( ( A A) A A))))]
[(_ (~and norun #:norun) {∀-type:id } A:expr B:expr d:≥0)
(define/with-syntax local-map (generate-temporary #'map))
#`(dbg norun
(let ()
(: local-map
( (∀-type )
( ( A B) (Deep-Listof d A) (Deep-Listof d B))
;; Use the type below to allow identity functions, but it's
;; more heavy on the typechecker
#;(case→ ( ( A B) (Deep-Listof d A) (Deep-Listof d B))
( ( A A) (Deep-Listof d A) (Deep-Listof d A)))))
(define (local-map f l)
(if (null? l)
'()
(cons ((λdeep-map {∀-type } A B #,(sub1 (syntax-e #'d)))
f (car l))
(local-map f (cdr l)))))
local-map))]))
(define-syntax (deep-map stx)
(syntax-parse stx
[(_ {∀-type:id } A:expr B:expr d:≥0 f:expr l:expr)
(syntax/loc #'f ((λdeep-map {∀-type } A B d) f l))]))
;; We provide hints for the types of some common functions
(define-type-expander (ArgOf stx)
(syntax-parse stx
[(_ (~literal length) T:expr R) #'(Listof Any)]
[(_ (~literal car) T:expr R) #'(Pairof T Any)]
[(_ (~literal car!) T:expr R) #'(U (Listof T) (Pairof T Any))]
[(_ (~literal cdr) T:expr R) #'(Pairof Any T)]
[(_ (~literal list) T:expr R) #'T]
[(_ ((~literal λget) f ) T:expr R) #'(has-get T f )]
;; Default case:
[(_ f:expr T:expr R) #'T]))
(define-type-expander (ResultOf stx)
(syntax-parse stx
[(_ (~literal length) T:expr R) #'Index]
[(_ (~literal car) T:expr R) #'T]
[(_ (~literal car!) T:expr R) #'T]
[(_ (~literal cdr) T:expr R) #'T]
[(_ (~literal list) T:expr R) #'(List T)]
[(_ ((~literal λget) f ) T:expr R) #'(result-get T f )]
;; Default case:
[(_ f:expr T:expr R) #'R]))
(define-syntax (substitute-function stx)
(syntax-parse stx
[(_ (~literal list)) #'(λ #:∀ (X) ([x : X]) : (List X) (list x))]
;; Default case:
[(_ f:expr) #'f]))
(define-syntax/parse (deep-map-auto d:≥0 f l)
#'(deep-map {A B} (ArgOf f A B) (ResultOf f A B) d (substitute-function f) l))
;; Now we turn all map: calls into the form
;; (compose-maps [(d f) …] [l …])
(define-syntax (compose-maps stx)
(syntax-parse stx
[(_ [] [l])
#'l]
[(_ [] [l:expr ])
#'(values l )]
[(_ [(d:≥0 f:expr) (d-rest:≥0 f-rest:expr) ] [l:expr ])
#'(deep-map-auto d f (compose-maps [(d-rest f-rest) ] [l ]))]))
(define-for-syntax (transform-map: depth stx)
(syntax-parse stx
[((~literal curry) (~literal map) f:expr)
(transform-map: (add1 depth) #'f)]
[((~literal compose) f:expr )
(define/syntax-parse (([dd ff] ) )
(stx-map (curry transform-map: depth) #'(f )))
#`[(dd ff) ]]
[(~literal identity) #'[]]
[(~literal values) #'[]]
[f:expr
#`[(#,depth f)]]))
(define-syntax (map: stx)
(syntax-parse stx
[(_ f l) #`(compose-maps #,(transform-map: 1 #'f) [l])]))