#lang racket/base
;; Copyright (c) 2018 Joel Dueck.
;;
;; Licensed under the Apache License, Version 2.0 (the "License");
;; you may not use this file except in compliance with the License.
;; A copy of the License is included with this source code, in the
;; file "LICENSE.txt".
;; You may also obtain a copy of the License at
;;
;; http://www.apache.org/licenses/LICENSE-2.0
;;
;; Unless required by applicable law or agreed to in writing, software
;; distributed under the License is distributed on an "AS IS" BASIS,
;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;; See the License for the specific language governing permissions and
;; limitations under the License.
;;
;; Author contact information:
;; joel@jdueck.net
;; https://joeldueck.com
;; -------------------------------------------------------------------------
;; Tag functions used by pollen.rkt when HTML is the output format.
(require (for-syntax racket/base racket/syntax))
(require racket/list
racket/function
pollen/decode
pollen/tag
txexpr
"dust.rkt")
(provide html-fn
html-fndef)
;; Customized paragraph decoder replaces single newlines within paragraphs
;; with single spaces instead of <br> tags. Allows for “semantic line wrapping”.
(define (decode-hardwrapped-paragraphs xs)
(define (no-linebreaks xs)
(decode-linebreaks xs " "))
(decode-paragraphs xs #:linebreak-proc no-linebreaks))
;; A shortcut macro: lets me define a whole lot of tag functions of the form:
;; (define html-p (default-tag-function 'p)
(define-syntax (provide/define-html-default-tags stx)
(syntax-case stx ()
[(_ TAG ...)
(let ([tags (syntax->list #'(TAG ...))])
(with-syntax ([((HTML-TAG-FUNC HTML-TAG) ...)
(for/list ([htag (in-list tags)])
(list (format-id stx "html-~a" (syntax-e htag)) (syntax-e htag)))])
#'(begin
(provide HTML-TAG-FUNC ...)
(define HTML-TAG-FUNC (default-tag-function 'HTML-TAG)) ...)))]))
;; Here we go:
(provide/define-html-default-tags p
b
strong
i
em
strike
ol
ul
sup
blockquote
code)
(provide html-root
html-item
html-section
html-subsection
html-newthought
html-smallcaps
html-center
html-blockcode
html-verse
html-link
html-url
html-fn
html-fndef
html-note)
(define html-item (default-tag-function 'li))
(define html-section (default-tag-function 'h2))
(define html-subsection (default-tag-function 'h3))
(define html-newthought (default-tag-function 'span #:class "newthought"))
(define html-smallcaps (default-tag-function 'span #:class "smallcaps"))
(define html-center (default-tag-function 'div #:style "text-align: center"))
(define-tag-function (html-root attrs elements)
(define first-pass
(decode-elements elements
#:txexpr-elements-proc decode-hardwrapped-paragraphs
#:exclude-tags '(script style figure table pre)))
(define second-pass
(decode-elements first-pass
#:block-txexpr-proc detect-newthoughts
#:inline-txexpr-proc decode-link-urls
#:string-proc (compose1 smart-quotes smart-dashes)
#:exclude-tags '(script style pre code)))
`(body ,@second-pass ,(html-footnote-block)))
(define-tag-function (html-blockcode attrs elems)
(define file (or (assoc 'filename attrs) ""))
(define codeblock `(pre [[class "code"]] (code ,@elems)))
(cond [(string>? file "") `(@ (div [[class "listing-filename"]] 128196 " " ,file) ,codeblock)]
[else codeblock]))
(define-tag-function (html-verse attrs elems)
(let* ([title (or (assoc 'title attrs) "")]
[italic? (assoc 'italic attrs)]
[pre-attrs (cond [italic? '([class "verse"] [style "font-style: italic"])]
[else '([class "verse"])])]
[pre-title (cond [(string>? title "") '(p [[class "verse-heading"]] ,title)]
[else ""])])
`(div [[class "poem"]] (pre ,pre-attrs ,pre-title ,@elems))))
;; There is no way in vanilla CSS to create a selector for “p tags that contain
;; a span of class ‘newthought’”. So we can handle it at the Pollen processing level.
(define (detect-newthoughts block-xpr)
(define (is-newthought? tx) ; Helper function
(and (txexpr? tx)
(eq? 'span (get-tag tx))
(attrs-have-key? tx 'class)
(string=? "newthought" (attr-ref tx 'class))))
(if (and (eq? (get-tag block-xpr) 'p)
(is-newthought? (first (get-elements block-xpr))))
(attr-set block-xpr 'class "pause-before")
block-xpr))
;; Links
;;
;; Private use:
(define link-urls (make-hash))
;; Provided tag functions:
(define (html-link . args)
`(link& [[ref ,(format "~a" (first args))]] ,@(rest args)))
(define (html-url ref url)
(hash-set! link-urls (format "~a" ref) url))
;; Private use (by html-root):
(define (decode-link-urls tx)
(cond [(eq? (get-tag tx) 'link&)
(let* ([url-ref (attr-ref tx 'ref)]
[url (or (hash-ref link-urls url-ref #f)
(format "Missing reference: ~a" url-ref))])
`(a [[href ,url]] ,@(get-elements tx)))]
[else tx]))
;; Footnotes
;;
;; Private use:
(define fn-names null)
(define fn-definitions (make-hash))
(define (fn-id x) (string-append x "_fn"))
(define (fndef-id x) (string-append x "_fndef"))
;; Provided footnote tag functions:
(define (html-fn . args)
(define name (format "~a" (first args)))
(set! fn-names (cons name fn-names))
(let* ([def-anchorlink (string-append "#" (fndef-id name))]
[nth-ref (number->string (count (curry string=? name) fn-names))]
[ref-id (string-append (fn-id name) nth-ref)]
[fn-number (+ 1 (index-of (remove-duplicates (reverse fn-names)) name))]
[ref-text (format "(~a)" fn-number)])
(cond [(empty? (rest args)) `(sup (a [[href ,def-anchorlink] [id ,ref-id]] ,ref-text))]
[else `(span [[class "links-footnote"] [id ,ref-id]]
,@(rest args)
(sup (a [[href ,def-anchorlink]] ,ref-text)))])))
(define (html-fndef . elems)
(hash-set! fn-definitions (format "~a" (first elems)) (rest elems)))
;; Private use (by html-root)
(define (html-footnote-block)
(define note-items
(for/list ([fn-name (in-list (remove-duplicates (reverse fn-names)))])
(let* ([definition-text (or (hash-ref fn-definitions fn-name #f)
'((i "Missing footnote definition!")))]
[backref-count (count (curry string=? fn-name) fn-names)]
[backrefs (for/list ([fnref-num (in-range backref-count)])
`(a [[href ,(string-append "#"
(fn-id fn-name)
(format "~a" (+ 1 fnref-num)))]] "↩"))])
`(li [[id ,(fndef-id fn-name)]] ,@definition-text ,@backrefs))))
(cond [(null? note-items) ""]
[else `(section ((class "footnotes")) (hr) (ol ,@note-items))]))
(define-tag-function (html-note attrs elems)
(txexpr 'note attrs (decode-paragraphs elems #:force? #t)))
