add backslash escapes

Makefile.am

@@ -5,6 +5,7 @@ godir=$(prefix)/share/guile/site/2.0
 
 SOURCES =                           \
   commonmark/utils.scm              \
+  commonmark/common.scm             \
   commonmark/node.scm               \
   commonmark/blocks.scm             \
   commonmark/inlines.scm            \

commonmark/blocks.scm

@@ -21,12 +21,12 @@
   #:use-module (ice-9 regex)
   #:use-module (commonmark node)
   #:use-module (commonmark utils)
+  #:use-module (commonmark common)
   #:export (parse-blocks))
 
 ;; ']' needs to be the first character after an openning '[' to be able
 ;; to match ']'
-(define ascii-punctuation-characters "[]!\"#$%&'()*+,-./:;<=>?@[\\^_`{|}~]")
-(define escaped-characters (string-append "\\\\" ascii-punctuation-characters))
+(define escaped-characters (string-append "\\\\[" ascii-punctuation-characters "]"))
 (define regular-characters "[^\x01-\x19 ()\\\\]")
 (define in-parens-no-space (string-append "\\((" regular-characters "|" escaped-characters "|\\\\)*\\)"))
 (define link-label (string-append "\\[(([^][]|"

commonmark/common.scm

@@ -0,0 +1,23 @@
+;; Copyright (C) 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 common) 
+  #:export (ascii-punctuation-characters))
+
+;; ']' needs to be the first character after an openning '[' to be able
+;; to match ']'
+(define ascii-punctuation-characters "]!\"#$%&'()*+,-./:;<=>?@[\\^_`{|}~")

commonmark/inlines.scm

@@ -22,6 +22,7 @@
   #:use-module (srfi srfi-9)
   #:use-module (srfi srfi-26)
   #:use-module (commonmark node)
+  #:use-module (commonmark common)
   #:export (parse-inlines))
 
 (define re-start-ticks (make-regexp "^`+"))
@@ -207,6 +208,24 @@
                             delim-stack
                             nodes-stack)))))
 
+(define (ascii-punctuation-characters? ch)
+  (define ascii-punc-set (string->char-set ascii-punctuation-characters))
+  (char-set-contains? ascii-punc-set ch))
+
+(define (parse-backslash text nodes delim-stack nodes-stack)
+  (let* ((next-ch-text (text-advance text 1))
+         (next-ch (text-char next-ch-text)))
+    (cond ((char=? next-ch #\newline)
+           (parse-char (text-advance next-ch-text 1)
+                       (cons (make-hardbreak-node) nodes)
+                       delim-stack nodes-stack))
+          ((ascii-punctuation-characters? next-ch)
+           (parse-char (text-advance next-ch-text 1)
+                       (cons (make-text-node (string next-ch)) nodes)
+                       delim-stack nodes-stack))
+          (else (parse-char next-ch-text (cons (make-text-node "\\") nodes)
+                            delim-stack nodes-stack)))))
+
 (define (parse-ticks text nodes delim-stack nodes-stack)
   (let ((start-ticks (start-ticks? text)))
     (let loop ((end-ticks (end-ticks? (text-move text (match:end start-ticks 0)))))
@@ -239,6 +258,7 @@
   (if (text-end? text)
       (pop-remaining-delim nodes delim-stack nodes-stack)
       (case (text-char text)
+        ((#\\) (parse-backslash text nodes delim-stack nodes-stack))
         ((#\`) (parse-ticks text nodes delim-stack nodes-stack))
         ((#\* #\_) (parse-emphasis text nodes delim-stack nodes-stack))
         (else (parse-normal-text text nodes delim-stack nodes-stack)))))

commonmark/node.scm

@@ -53,6 +53,8 @@
             text-node?
             make-softbreak-node
             softbreak-node?
+            make-hardbreak-node
+            hardbreak-node?
             make-blank-node
             blank-node?
             make-code-span-node
@@ -81,6 +83,7 @@
 ;; - 'heading
 ;; - 'text
 ;; - 'softbreak
+;; - 'hardbreak
 ;; - 'blank
 ;; - 'code-span
 ;; - 'emphasis
@@ -251,6 +254,13 @@
 (define (softbreak-node? n)
   (node-type? n 'softbreak))
 
+;; Hardbreak node
+(define (make-hardbreak-node)
+  (make-node 'hardbreak '((closed . #t))))
+
+(define (hardbreak-node? n)
+  (node-type? n 'hardbreak))
+
 ;; Blank node
 (define (make-blank-node)
   (make-node 'blank '((closed . #t))))