lib/markdown2: introduce maths mode

Signed-off-by: Alexandre Terrasa <[email protected]>

lib/markdown2/markdown_html_rendering.nit

@@ -18,11 +18,20 @@ module markdown_html_rendering
 import markdown_rendering
 import markdown_github
 import markdown_wikilinks
+import markdown_maths
+
+import md5
 
 # Markdown document renderer to HTML
 class HtmlRenderer
 	super MdRenderer
 
+	# Output directory for Maths mode images
+	#
+	# If `null`, do not generate images.
+	# Default: `null`.
+	var maths_img_outdir: nullable String = null is writable
+
 	# HTML output under construction
 	private var html: Buffer is noinit
 
@@ -456,3 +465,30 @@ redef class MdWikilink
 		v.add_raw "</wiki>"
 	end
 end
+
+# Math mode
+
+redef class MdMaths
+	redef fun render_html(v) do
+		var out_dir = v.maths_img_outdir
+
+		if out_dir == null then
+			v.add_raw opening_delimiter
+			v.add_raw literal or else ""
+			v.add_raw closing_delimiter
+			return
+		end
+
+		# generate image
+		out_dir.mkdir
+		var maths = literal or else ""
+		var out = "{out_dir}/{maths.md5}.png"
+		if not out.file_exists then
+			sys.system "tex2im -o {out} -z -n -r 200x200 \"{maths.escape_to_sh}\""
+		end
+
+		v.add_raw "<img alt=\""
+		v.add_text literal or else ""
+		v.add_raw "\" src=\"{out}\" />"
+	end
+end

lib/markdown2/markdown_latex_rendering.nit

@@ -18,6 +18,7 @@ module markdown_latex_rendering
 import markdown_rendering
 import markdown_github
 import markdown_wikilinks
+import markdown_maths
 
 # Markdown document renderer to LaTeX
 class LatexRenderer
@@ -436,3 +437,13 @@ redef class MdWikilink
 		v.add_raw "\}"
 	end
 end
+
+# Math mode
+
+redef class MdMaths
+	redef fun render_latex(v) do
+		v.add_raw "$"
+		v.add_raw literal or else ""
+		v.add_raw "$"
+	end
+end

lib/markdown2/markdown_man_rendering.nit

@@ -18,6 +18,7 @@ module markdown_man_rendering
 import markdown_rendering
 import markdown_github
 import markdown_wikilinks
+import markdown_maths
 
 # Markdown document renderer to Manpage
 class ManRenderer
@@ -256,3 +257,13 @@ redef class MdWikilink
 		v.add ")"
 	end
 end
+
+# Math mode
+
+redef class MdMaths
+	redef fun render_man(v) do
+		v.add "$"
+		v.add literal or else ""
+		v.add "$"
+	end
+end

lib/markdown2/markdown_maths.nit

@@ -0,0 +1,146 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may 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.
+
+# Markdown Maths mode
+#
+# Allows to write Maths equation with the LaTeX Maths mode.
+#
+# This mode requires `tex2im` to be installed and added to the path.
+# See: <http://www.nought.de/tex2im.php>
+module markdown_maths
+
+intrude import markdown_inline_parsing
+intrude import markdown_block_parsing
+
+redef class MdParser
+
+	# Enable maths mode
+	var maths_mode = false is writable
+
+	redef var inline_parser is lazy do
+		var parser = super
+		parser.maths_mode = maths_mode
+		return parser
+	end
+end
+
+redef class MdInlineParser
+
+	# Enable maths mode
+	private var maths_mode = false
+
+	redef var delimiter_processors is lazy do
+		var processors = super
+		if maths_mode then
+			processors.add new MdMathsProcessor
+		end
+		return processors
+	end
+end
+
+# Maths equation processor
+class MdMathsProcessor
+	super MdDelimiterProcessor
+
+	# Maths equation delimiter
+	#
+	# Default is `$`.
+	var delimiter_char = '$'
+
+	redef var min_length = 1
+	redef fun opening_delimiter do return delimiter_char
+	redef fun closing_delimiter do return delimiter_char
+	redef fun delimiter_use(opener, closer) do return 1
+
+	redef fun process(opener, closer, delimiter_use) do
+		var node = new MdMaths(
+			new MdLocation(
+				opener.location.line_start, opener.location.column_start,
+				closer.location.line_end, closer.location.column_end),
+			opening_delimiter.to_s)
+
+		var buffer = new Buffer
+		var tmp = opener.next
+		while tmp != null and tmp != closer do
+			var next = tmp.next
+			tmp.maths_literal(buffer)
+			tmp.unlink
+			tmp = next
+		end
+		node.literal = buffer.to_s
+		opener.insert_after(node)
+	end
+end
+
+# Math equation node
+class MdMaths
+	super MdDelimited
+
+	# Literal Maths string
+	var literal: nullable String = null
+end
+
+# Inline nodes
+
+redef class MdNode
+
+	# Return the content of the node as a literal string
+	private fun maths_literal(buffer: Buffer) do
+		var node = first_child
+		while node != null do
+			node.maths_literal(buffer)
+			node = node.next
+		end
+	end
+end
+
+redef class MdCode
+	redef fun maths_literal(buffer) do buffer.append "{delimiter}{literal}{delimiter}"
+end
+
+redef class MdDelimited
+	redef fun maths_literal(buffer) do
+		buffer.append opening_delimiter
+		super
+		buffer.append closing_delimiter
+	end
+end
+
+redef class MdHtmlInline
+	redef fun maths_literal(buffer) do buffer.append literal
+end
+
+redef class MdLinkOrImage
+	redef fun maths_literal(buffer) do
+		if self isa MdLink and is_autolink then
+			buffer.append "<{destination}>"
+			return
+		end
+		if self isa MdImage then
+			buffer.append "!"
+		end
+		buffer.append "["
+		super
+		buffer.append "]"
+		buffer.append "({destination})"
+	end
+end
+
+redef class MdLink
+	redef fun maths_literal(buffer) do buffer.append "[{title or else ""}]({destination})"
+end
+
+redef class MdText
+	redef fun maths_literal(buffer) do buffer.append literal
+end

lib/markdown2/markdown_md_rendering.nit

@@ -18,6 +18,7 @@ module markdown_md_rendering
 import markdown_rendering
 import markdown_github
 import markdown_wikilinks
+import markdown_maths
 
 # Markdown document renderer to Markdown
 class MarkdownRenderer
@@ -390,3 +391,13 @@ redef class MdWikilink
 		v.add_raw "]]"
 	end
 end
+
+# Math mode
+
+redef class MdMaths
+	redef fun render_md(v) do
+		v.add_raw "$"
+		v.add_raw literal or else ""
+		v.add_raw "$"
+	end
+end