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;; Copyright (C) 2015, 2016 Erik Edrosa <erik.edrosa@gmail.com>
;;
;; This file is part of guile-commonmark
;;
;; guile-commonmark is free software: you can redistribute it and/or
;; modify it under the terms of the GNU Lesser General Public License
;; as published by the Free Software Foundation, either version 3 of
;; the License, or (at your option) any later version.
;;
;; guile-commonmark is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU Lesser General Public License for more details.
;;
;; You should have received a copy of the GNU Lesser General Public License
;; along with guile-commonmark. If not, see <http://www.gnu.org/licenses/>.
(define-module (commonmark blocks)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (commonmark node)
#:use-module (commonmark utils)
#:use-module (commonmark parser)
#:use-module (commonmark common)
#:export (parse-blocks))
;; Port -> Document
(define (parse-blocks port)
"Parses CommonMark blocks from PORT returning a CommonMark Document tree"
(let loop ((root (make-document-node))
(line (read-line-without-nul port)))
(if (eof-object? line)
(parse-clean-up root (lambda (doc references)
(if (null? references)
doc
(node-add-data doc 'link-references references))))
(loop (parse-open-block root (make-parser line))
(read-line-without-nul port)))))
;; Node Parser -> Node
(define (parse-open-block node parser)
(cond ((node-closed? node) node)
((document-node? node) (parse-container-block node parser))
((block-quote-node? node) (parse-block-quote node parser))
((code-block-node? node) (parse-code-block node parser))
((fenced-code-node? node) (parse-fenced-code node parser))
((list-node? node) (parse-list node parser))
((paragraph-node? node) (parse-paragraph node parser))))
;; Node Parser -> Node
(define (parse-container-block node parser)
(cond ((and (no-children? node) (empty-line parser)) ;; empty line
node)
((no-children? node) ;; first line
(add-child-node node (parse-line parser)))
((and (node-closed? (last-child node)) (not (empty-line parser))) ;; new block
(add-child-node node (parse-line parser)))
(else (let ((new-child (parse-open-block (last-child node) parser)))
(cond ((and (not (empty-line parser))
(node-closed? new-child)
(not (fenced-code-node? new-child))
(not (heading-node? new-child)))
(add-child-node (replace-last-child node new-child)
(parse-line parser)))
(else (replace-last-child node new-child)))))))
(define (parse-block-quote node parser)
(cond ((block-quote (parser-advance-min-spaces parser 3)) => (lambda (rest)
(parse-container-block node (block-quote-rest rest))))
((open-descendant? node 'paragraph) ;; lazy continuation line
(let ((parsed-line (parse-line parser)))
(if (or (paragraph-node? parsed-line) (code-block-node? parsed-line))
(parse-container-block node parser)
(close-node node))))
(else (close-node node))))
(define (parse-code-block node parser)
(let ((nonspace-parser (parser-advance-next-nonspace parser)))
(cond ((parser-indented? parser nonspace-parser)
(add-child-node node (parser-rest-str (parser-advance parser code-indent))))
((empty-line parser) (add-child-node node ""))
(else (close-node node)))))
(define (parse-paragraph node parser)
(let ((parsed-line (parse-line parser)))
(cond ((blank-node? parsed-line)
(close-node node))
((and (setext-heading (parser-advance-min-spaces parser 3)) (= (length (node-children (last-child node))) 1))
(make-heading-node (last-child (last-child node))
(if (string-any #\= (parser-rest-str parser)) 1 2)))
((paragraph-node? parsed-line)
(replace-last-child node (join-text-nodes (last-child node) (last-child parsed-line))))
((code-block-node? parsed-line)
(replace-last-child node (add-text (last-child node) (parser-rest-str parser))))
(else (close-node node)))))
(define (fence-start node)
(node-get-data node 'fence-start))
(define (fence-type node)
(node-get-data node 'fence))
(define (parse-fenced-code node parser)
(cond ((fenced-code-end (parser-advance-min-spaces parser 3) (fence-type node))
(close-node node))
((no-children? node)
(add-child-node node (parser-rest-str (parser-advance-min-spaces parser (fence-start node)))))
(else (replace-last-child
node
(string-append (last-child node)
"\n"
(parser-rest-str (parser-advance-min-spaces parser (fence-start node))))))))
(define (list-type node)
(node-get-data node 'type))
(define (list-bullet node)
(node-get-data node 'bullet))
(define (list-delimiter node)
(node-get-data node 'delimiter))
(define (eq-list-types? l1 l2)
(or (and (eq? (list-type l1) (list-type l2) 'bullet)
(string=? (list-bullet l1) (list-bullet l2)))
(and (eq? (list-type l1) (list-type l2) 'ordered)
(string=? (list-delimiter l1) (list-delimiter l2)))))
(define (parse-list node parser)
(define (remove-blank-node item)
(if (blank-last-child? item)
(remove-last-child item)
item))
(define (parse-new-item node parser item)
(let ((new-list (parse-line parser)))
(cond ((and (list-node? new-list)
(eq-list-types? node new-list))
(add-child-node (replace-last-child node item)
(last-child new-list)))
(else (close-node (replace-last-child node (remove-blank-node item)))))))
(if (node-closed? (last-child node))
(parse-new-item node parser (last-child node))
(let ((item (parse-item (last-child node) parser)))
(cond ((and (node-closed? item) (empty-line parser))
(close-node (replace-last-child node item)))
((node-closed? item)
(parse-new-item node parser item))
(else (replace-last-child node item))))))
(define (n-spaces? n str)
(>= (string-index str (lambda (c) (not (char=? #\space c)))) n))
(define (item-padding node)
(node-get-data node 'padding))
(define (blank-last-child? node)
(and (not (no-children? node)) (blank-node? (last-child node))))
(define (parse-item node parser)
(let ((padding (item-padding node)))
(cond ((and (blank-last-child? node) (= (length (node-children node)) 1))
(close-node node))
((and (empty-line parser) (no-children? node))
(add-child-node node (make-blank-node)))
((and (empty-line parser) (blank-node? (last-child node)))
node) ;; may be separated by more than one blank line
((empty-line parser)
(cond ((open-descendant? node 'fenced-code)
(parse-container-block node parser))
((list-node? (last-child node))
(let ((container (parse-container-block node parser)))
(if (node-closed? (last-child container))
(close-node container)
(add-child-node container (make-blank-node)))))
((open-descendant? node 'code-block)
(add-child-node (parse-container-block node parser)
(make-blank-node)))
(else (add-child-node (replace-last-child node (close-node (last-child node)))
(make-blank-node)))))
((n-spaces? padding (parser-rest-str parser))
(let* ((parser (parser-advance parser padding))
(n (if (and (blank-last-child? node) (or (prev-node? node 'code-block) (prev-node? node 'list)))
(remove-last-child node)
node))
(new-item (parse-container-block n parser)))
(if (and (blank-last-child? node) (prev-node? new-item 'list) (prev-node-closed? new-item))
(add-child-node (replace-last-child new-item (last-child node)) (last-child new-item))
new-item)))
((or (no-children? node) (blank-node? (last-child node)))
(close-node node))
((open-descendant? node 'paragraph)
(let ((parsed-line (parse-line (parser-advance-min-spaces parser padding))))
(if (paragraph-node? parsed-line)
(parse-container-block node parser)
(close-node (replace-last-child node (close-node (last-child node)))))))
(else (close-node (replace-last-child node (close-node (last-child node))))))))
(define (heading-level str)
(string-length str))
;; Parser -> Node
(define (parse-line parser)
(let ((nonspace-parser (parser-advance-next-nonspace parser)))
(cond ((empty-line nonspace-parser) (make-blank-node))
((parser-indented? parser nonspace-parser) (make-code-block parser))
((thematic-break nonspace-parser) (make-thematic-break))
((block-quote nonspace-parser) => make-block-quote)
((atx-heading nonspace-parser) => make-atx-heading)
((fenced-code nonspace-parser) => make-fenced-code)
((bullet-list-marker nonspace-parser) => (cut make-bullet-list-marker parser <>))
((ordered-list-marker nonspace-parser) => (cut make-ordered-list-marker parser <>))
(else (make-paragraph nonspace-parser)))))
(define (make-thematic-break)
(make-thematic-break-node))
(define (make-block-quote match)
(make-block-quote-node (parse-line (block-quote-rest match))))
(define (make-atx-heading match)
(make-heading-node (atx-heading-content match)
(heading-level (atx-heading-opening match))))
(define (make-code-block parser)
(make-code-block-node (parser-rest-str (parser-advance parser code-indent))))
(define (make-fenced-code match)
(make-fenced-code-node
`((fence . ,(fenced-code-fence match))
(fence-start . ,(fenced-code-start match))
(info-string . ,(unescape-string (string-trim-both (fenced-code-info-string match)))))))
(define (make-bullet-list-marker parser match)
(let ((rest-parser (bullet-list-rest parser match)))
(make-list-node (make-item rest-parser
(bullet-list-offset parser rest-parser)
(bullet-list-spaces rest-parser))
`((type . bullet)
(tight . #t)
(bullet . ,(bullet-list-bullet match))))))
(define (make-ordered-list-marker parser match)
(let ((rest-parser (ordered-list-rest parser match)))
(make-list-node (make-item rest-parser
(ordered-list-offset parser rest-parser)
(ordered-list-spaces rest-parser))
`((type . ordered)
(start . ,(ordered-list-number match))
(tight . #t)
(delimiter . ,(ordered-list-delimiter match))))))
(define (make-item parser width spaces)
(cond ((>= spaces 5)
(make-item-node (parse-line (parser-advance parser 1))
(+ width 1)))
((< spaces 1)
(make-item-node #f (+ width 1)))
(else (make-item-node (parse-line (parser-advance parser spaces)) (+ width spaces)))))
(define (make-paragraph parser)
(make-paragraph-node (parser-rest-str parser)))
(define (parse-clean-up node col)
(cond ((not (node? node)) (col node '()))
((code-block-node? node) (remove-empty-lines node col))
((paragraph-node? node) (parse-reference-definition node col))
((list-node? node) (clean-list-nodes node col))
((item-node? node) (remove-blank-nodes node col))
(else (filter-map&co parse-clean-up (node-children node)
(lambda (v d)
(col (make-node (node-type node)
(node-data node)
v)
d))))))
(define (reverse-join ls)
(reduce (cut string-append <> "\n" <>) "" ls))
(define (parse-reference-definition node col)
(let loop ((text (reverse-join (node-children (last-child node))))
(links '()))
(cond ((link-definition text) =>
(lambda (match)
(loop (link-definition-rest match)
(cons (list (string-map char-downcase (link-definition-label match))
(link-definition-destination match)
(link-definition-title match))
links))))
(else (col (if (= (string-length text) 0)
#f
(make-paragraph-node (string-trim-right text))) links)))))
(define (remove-empty-lines node col)
(col (make-node (node-type node) (node-data node)
(list (reverse-join (drop-while (cut string-every char-set:blank <>)
(node-children node)))))
'()))
(define (clean-list-nodes node col)
(define (any-blank-nodes? item)
(any blank-node? (node-children item)))
(let ((blank-nodes (any any-blank-nodes? (node-children node))))
(filter-map&co parse-clean-up (node-children node)
(lambda (v d)
(col (make-node (node-type node)
(if blank-nodes
(acons 'tight #f (node-data node))
(node-data node))
v)
d)))))
(define (remove-blank-nodes node col)
(cond ((no-children? node) (col node '()))
(else (filter-map&co parse-clean-up (filter (negate blank-node?) (node-children node))
(lambda (v d)
(col (make-node (node-type node)
(node-data node)
v)
d))))))
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