hyper-literate/collects/help/search.ss
Eli Barzilay de4f8a0e35 search improvements
svn: r8565

original commit: de82823bfa5c3ab4c4e7d220cd80840d9e13866c
2008-02-07 17:22:55 +00:00

186 lines
7.8 KiB
Scheme

#lang scheme/base
(require setup/xref
scribble/xref
scribble/struct
scribble/manual-struct
scribble/decode
scribble/manual
(prefix-in scheme: scribble/scheme)
net/sendurl
net/uri-codec
mzlib/contract
setup/dirs)
(provide/contract [send-main-page (-> void?)])
(provide perform-search)
(define (send-main-page)
(let* ([path (build-path (find-user-doc-dir) "index.html")]
[path (if (file-exists? path)
path (build-path (find-doc-dir) "index.html"))])
(send-url/file path)))
;; Configuration of search results
(define maximum-entries 500)
(define exact-score 1000)
(define exact-word-score 600)
(define words1-score 400)
(define words2-score 200)
(define prefix-score 100)
(define suffix-score 20)
(define contain-score 10)
(define exported-entry-bonus 200) ; prefer bindings and modules
(define regexp-score-factor 1.25) ; regexps get higher score
(define nomatch-score -1) ; prefer less irrelevant terms
(define (perform-search terms #:exact? [exact? #f] #:go-if-one? [go-if-one? #t])
(if (null? terms)
(send-main-page)
(let* ([xref (load-collections-xref)]
[scorer (terms->scorer terms exact?)]
[entries (xref-index xref)]
[entries
(let loop ([es entries] [r '()])
(if (null? es)
r
(loop (cdr es)
(let* ([e (car es)] [score (scorer e)])
(if (score . > . 0) (cons (cons score e) r) r)))))]
[entries (map cdr (sort entries scored-entry<?))])
(if (and go-if-one? (= 1 (length entries)))
(let*-values ([(tag) (entry-tag (car entries))]
[(path tag) (xref-tag->path+anchor xref tag)])
(send-url/file path #:fragment (uri-encode tag)))
(let* ([file (next-search-results-file)]
[term->label
(λ (t) (format "``~a''" (if (regexp? t) (object-name t) t)))]
[search-title ; note: terms is not null at this point (see above)
(apply string-append (term->label (car terms))
(map (λ (x) (format ", ~a" (term->label x)))
(cdr terms)))]
[search-title (string-append "Search results for " search-title)]
[contents
(if (null? entries)
(list (make-element "schemeerror" (list "No results found.")))
(build-itemization entries))]
[contents (cons (title search-title) contents)])
(xref-render xref (decode contents) file)
(send-url/file file))))))
;; converts a list of search terms to a scoring function
(define (terms->scorer terms exact?)
;; turns a string to one that matches word prefixes (eg turn a "reg-qu"
;; string to "reg\\w*-qu\\w*"), as with convenient completers like Emacs or
;; zsh.
(define (words-rx str pat)
(let* ([strs (reverse (map (lambda (s) (regexp-quote s #f))
(regexp-split #px"(?<=\\w)\\b" str)))]
[strs (cons (car strs)
(map (lambda (s) (string-append s pat)) (cdr strs)))])
(string-append "^" (apply string-append (reverse strs)) "$")))
(define scorers
(map (lambda (term)
(let* ([rx? (regexp? term)]
[rx (if rx? (object-name term) (regexp-quote term #f))]
;; note: still works if we're given a regexp with ^/$ anchors
[exact (regexp (format "^~a$" rx))]
[prefix (regexp (format "^~a" rx))]
[suffix (regexp (format "~a$" rx))]
[exact-word (and (not rx?) (pregexp (format "\\b~a\\b" rx)))]
[words1 (and (not rx?) (pregexp (words-rx term "\\w*")))]
[words2 (and (not rx?) (pregexp (words-rx term ".*")))]
[contain (if rx? term (regexp rx))])
(lambda (str)
(let* ([match? (lambda (rx) (and rx (regexp-match? rx str)))]
[sc (cond [(match? exact) exact-score]
[exact? nomatch-score]
[(match? exact-word) exact-word-score]
[(match? words1) words1-score]
[(match? words2) words2-score]
[(match? prefix) prefix-score]
[(match? suffix) suffix-score]
[(match? contain) contain-score]
[else nomatch-score])]
[sc (if (and rx? (sc . > . 0))
(* sc regexp-score-factor)
sc)])
sc))))
terms))
(lambda (entry)
(foldl (lambda (word acc)
(+ acc (foldl (lambda (sc acc) (+ acc (sc word))) 0 scorers)))
;; give some bonus for bindings and modules
(let ([desc (entry-desc entry)])
(if (or (exported-index-desc? desc)
(module-path-index-desc? desc))
exported-entry-bonus
0))
(entry-words entry))))
(define (scored-entry<? x y)
(let ([xsc (car x)] [ysc (car y)])
(cond [(> xsc ysc) #t]
[(< xsc ysc) #f]
[else (let loop ([xs (entry-words (cdr x))]
[ys (entry-words (cdr y))])
(cond [(null? ys) #f]
[(null? xs) #t]
[(string-ci=? (car xs) (car ys))
(or (loop (cdr xs) (cdr ys))
;; Try string<? so "Foo" still precedes "foo"
(string<? (car xs) (car ys)))]
[else (string-ci<? (car xs) (car xs))]))])))
(define next-search-results-file
(let ([n -1] [tmp (find-system-path 'temp-dir)])
(lambda ()
(set! n (modulo (add1 n) 10))
(build-path tmp (format "search-results-~a.html" n)))))
;; build-itemization : (nonempty-listof entry) -> (listof <stuff>)
(define (build-itemization entries)
(define entries*
(if (<= (length entries) maximum-entries)
entries
(let loop ([n maximum-entries] [es entries] [r '()])
(if (or (null? es) (zero? n))
(reverse r)
(loop (sub1 n) (cdr es) (cons (car es) r))))))
(cons (apply itemize
(map (λ (entry)
(apply item
(make-link-element "indexlink"
(entry-content entry)
(entry-tag entry))
(make-extra-content (entry-desc entry))))
entries*))
(if (eq? entries* entries)
'()
(list (make-element "schemeerror"
(list (format "Search truncated after ~a hits."
maximum-entries)))))))
(define (make-extra-content desc)
;; Use `desc' to provide more details on the link:
(append
(if (method-index-desc? desc)
(list " method of "
;; This is bad. We need a more abstract way to take a
;; binding name and tag/source to create a Scheme link.
(make-element
"schemesymbol"
(list (make-link-element
"schemevaluelink"
(list (symbol->string (exported-index-desc-name desc)))
(method-index-desc-class-tag desc)))))
null)
(if (and (exported-index-desc? desc)
(not (null? (exported-index-desc-from-libs desc))))
(cons ", provided from "
(cdr (apply append
(map (lambda (lib) (list ", " (scheme:to-element lib)))
(exported-index-desc-from-libs desc)))))
null)))