qfwfq/punctiform-convergence/snipets.scm
nik gaffney e58bfc9877 lacking names
first reductions, simplifying of some leaves into anonymous functions.
2007-07-09 15:44:21 +02:00

133 lines
4.2 KiB
Scheme

;; -*- mode: scheme -*-
;;
;; based on snip-lib from the embedded-gui collection
(module snipets mzscheme
(require
(lib "class.ss")
(lib "etc.ss")
(lib "mred.ss" "mred")
(lib "list.ss")
(lib "contract.ss"))
;; a snip
(define snip? (is-a?/c snip%))
;; a snip to act as the varying argument to a recursive functions
(define linked-snip? (union snip? false/c))
;; a function to act on snips being mapped
(define snip-visitor? any/c ) ;((snip?) (listof any/c) . ->* . (void))
;; the rest of the lists passed to a snip mapping function
(define rest-lists? (listof (listof any/c)))
;; a class that contains a snip
(define editor? (is-a?/c editor<%>))
(provide/contract
(snip-width (snip? . -> . number?))
(snip-height (snip? . -> . number?))
(snip-x (snip? . -> . number?))
(snip-y (snip? . -> . number?))
(snip-parent (snip? . -> . (union editor? false/c)))
(fold-snip ((snip? any/c . -> . any/c) any/c linked-snip? . -> . any/c))
(for-each-snip any/c ) ;((snip-visitor? linked-snip?) rest-lists? . ->* . (void))
(map-snip any/c )) ;((snip-visitor? linked-snip?) rest-lists? . ->* . ((listof any/c)))
;; the width of a snip in the parent pasteboard
(define (snip-width snip)
(let ([left (box 0)]
[right (box 0)]
[pasteboard (snip-parent snip)])
(send pasteboard get-snip-location snip left (box 0) false)
(send pasteboard get-snip-location snip right (box 0) true)
(- (unbox right) (unbox left))))
;; the height of a snip in the parent pasteboard
(define (snip-height snip)
(let ([top (box 0)]
[bottom (box 0)]
[pasteboard (snip-parent snip)])
(send pasteboard get-snip-location snip (box 0) top false)
(send pasteboard get-snip-location snip (box 0) bottom true)
(- (unbox bottom) (unbox top))))
;; the x-ccordinate of a snip in the parent pasteboard
(define (snip-x snip)
(let ([x (box 0)]
[pasteboard (snip-parent snip)])
(send pasteboard get-snip-location snip x (box 0) false)
(unbox x)))
;; the y-ccordinate of a snip in the parent pasteboard
(define (snip-y snip)
(let ([y (box 0)]
[pasteboard (snip-parent snip)])
(send pasteboard get-snip-location snip (box 0) y false)
(unbox y)))
; ;; the minimum width of the snip
; (define (snip-min-width snip)
; (cond
; [(is-a? snip stretchable-snip<%>)
; (send snip get-aligned-min-width)]
; [else (snip-width snip)]))
;
; ;; the minimum height of the snip
; (define (snip-min-height snip)
; (cond
; [(is-a? snip stretchable-snip<%>)
; (send snip get-aligned-min-height)]
; [else (snip-height snip)]))
;
;; the pasteboard that contains the snip
(define (snip-parent snip)
(let ([admin (send snip get-admin)])
(if admin
(send admin get-editor)
false)))
;; the application of f on all snips from snip to the end in a foldl foldr mannor
(define (fold-snip f init-acc snip)
(let loop ([snip snip]
[acc init-acc])
(cond
[(is-a? snip snip%)
(loop (send snip next) (f snip acc))]
[else acc])))
;; applies the function to all the snips
(define (for-each-snip f first-snip . init-lists)
(let loop ([snip first-snip]
[lists init-lists])
(cond
[(is-a? snip snip%)
(apply f (cons snip (map first lists)))
(loop (send snip next)
(map rest lists))]
[else (void)])))
;; a list of f applied to each snip
(define (map-snip f first-snip . init-lists)
(let loop ([snip first-snip]
[lists init-lists])
(cond
[(is-a? snip snip%)
(cons (apply f (cons snip (map first lists)))
(loop (send snip next)
(map rest lists)))]
[else empty])))
; ;; true if the snip can be resized in the x dimention
; (define (stretchable-width? snip)
; (cond
; [(is-a? snip stretchable-snip<%>)
; (send snip stretchable-width)]
; [else false]))
;
; ;; true if the snip can be resized in the y dimention
; (define (stretchable-height? snip)
; (cond
; [(is-a? snip stretchable-snip<%>)
; (send snip stretchable-height)]
; [else false]))
)