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typesetting/quad/quadwriter/query.rkt

94 lines
3.6 KiB
Racket

#lang debug racket
(require quad/base "struct.rkt" "param.rkt")
(provide (all-defined-out))
(define (make-query-index q)
(define qs (let loop ([q q])
(cons q (append* (for/list ([elem (in-list (quad-elems q))]
#:when (quad? elem))
(loop elem))))))
(list->vector qs))
(define (string->key str #:this [this? #false])
(match str
["doc" 'doc]
[(or "section" "sec" "s") 'section]
[(or "page" "pg" "p") 'page]
[(or "column" "col" "c") 'column]
[(or "block" "b") 'block]
[(or "line" "ln" "l") 'line]))
(define preds (hasheq 'doc doc-quad?
'section section-quad?
'page page-quad?
'column column-quad?
'block block-quad?
'line line-quad?))
(define (parse-query str)
(for/list ([piece (in-list (string-split str ":"))])
(match (regexp-match #px"^(.*)\\[(.*?)\\]$" piece)
[#false (cons (string->key piece) #false)]
[(list _ name arg) (cons (hash-ref preds (string->key name)) (or (string->number arg)
(string->symbol arg)))])))
(define (vector-memf proc vec)
(for/first ([idx (in-range (vector-length vec))]
#:when (proc (vector-ref vec idx)))
idx))
(define (query quad-or-index query-str [starting-q #false])
(define vec (match quad-or-index
[(? quad? q) (make-query-index q)]
[idx idx]))
(for/fold ([vidx 0]
#:result (and vidx (vector-ref vec vidx)))
([query-piece (in-list (parse-query query-str))]
#:break (not vidx))
(match query-piece
[(cons pred 'this)
;; resolve `this` by finding the querying quad, and searching backward
(for/first ([vidx (in-range (vector-memq starting-q vec) -1 -1)]
#:when (pred (vector-ref vec vidx)))
vidx)]
[(cons pred count)
(for/fold ([vidx vidx]
;; sub 1 because return values add 1
;; and final result should be location of matching quad
#:result (and vidx (sub1 vidx)))
([seen (in-range count)]
#:break (not vidx))
(for/first ([vidx (in-range vidx (vector-length vec))]
#:when (pred (vector-ref vec vidx)))
;; add 1 so on next iteration, we can find next matcher
;; and won't re-find this one immediately
(add1 vidx)))])))
(module+ test
(require rackunit)
(define counter 0)
(define-syntax-rule (factory type proc)
(make-quad #:type type
#:elems (for/list ([i (in-range 3)])
(set! counter (add1 counter))
(define new-q (proc))
(quad-update! new-q
[tag (format "~a[~a]-~a" 'proc counter (gensym))])
(hash-set! (quad-attrs new-q) 'count counter)
new-q)))
(define (line) (make-quad #:type line-quad))
(define (block) (factory block-quad line))
(define (col) (factory column-quad block))
(define (page) (factory page-quad col))
(define (sec) (factory section-quad page))
(define (count q) (and q (quad-ref q 'count)))
(define doc (factory doc-quad sec))
(check-eq? (query doc "page[this]" (query doc "line[2]")) (query doc "page[1]"))
(check-equal? (count (query doc "sec[2]")) 242)
(check-false (query doc "sec[102]:line[1]"))
(check-equal? (count (query doc "sec[2]:pg[1]")) 162)
(check-equal? (count (query doc "sec[2]:pg[1]:ln[3]")) 128))