# HG changeset patch # User Tuomo Valkonen # Date 1237318769 -7200 # Node ID 30d76ecdd725732509248fc8f925c2a9193437bf Import markdown.lua diff -r 000000000000 -r 30d76ecdd725 markdown.lua --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/markdown.lua Tue Mar 17 21:39:29 2009 +0200 @@ -0,0 +1,1359 @@ +#!/usr/bin/env lua + +--[[ +# markdown.lua -- version 0.32 + + + +**Author:** Niklas Frykholm, +**Date:** 31 May 2008 + +This is an implementation of the popular text markup language Markdown in pure Lua. +Markdown can convert documents written in a simple and easy to read text format +to well-formatted HTML. For a more thourough description of Markdown and the Markdown +syntax, see . + +The original Markdown source is written in Perl and makes heavy use of advanced +regular expression techniques (such as negative look-ahead, etc) which are not available +in Lua's simple regex engine. Therefore this Lua port has been rewritten from the ground +up. It is probably not completely bug free. If you notice any bugs, please report them to +me. A unit test that exposes the error is helpful. + +## Usage + + require "markdown" + markdown(source) + +``markdown.lua`` exposes a single global function named ``markdown(s)`` which applies the +Markdown transformation to the specified string. + +``markdown.lua`` can also be used directly from the command line: + + lua markdown.lua test.md + +Creates a file ``test.html`` with the converted content of ``test.md``. Run: + + lua markdown.lua -h + +For a description of the command-line options. + +``markdown.lua`` uses the same license as Lua, the MIT license. + +## License + +Copyright © 2008 Niklas Frykholm. + +Permission is hereby granted, free of charge, to any person obtaining a copy of this +software and associated documentation files (the "Software"), to deal in the Software +without restriction, including without limitation the rights to use, copy, modify, merge, +publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons +to whom the Software is furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all copies +or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +THE SOFTWARE. + +## Version history + +- **0.32** -- 31 May 2008 + - Fix for links containing brackets +- **0.31** -- 1 Mar 2008 + - Fix for link definitions followed by spaces +- **0.30** -- 25 Feb 2008 + - Consistent behavior with Markdown when the same link reference is reused +- **0.29** -- 24 Feb 2008 + - Fix for
 blocks with spaces in them
+-	**0.28** -- 18 Feb 2008
+	-	Fix for link encoding
+-	**0.27** -- 14 Feb 2008
+	-	Fix for link database links with ()
+-	**0.26** -- 06 Feb 2008
+	-	Fix for nested italic and bold markers
+-	**0.25** -- 24 Jan 2008
+	-	Fix for encoding of naked <
+-	**0.24** -- 21 Jan 2008
+	-	Fix for link behavior.
+-	**0.23** -- 10 Jan 2008
+	-	Fix for a regression bug in longer expressions in italic or bold.
+-	**0.22** -- 27 Dec 2007
+	-	Fix for crash when processing blocks with a percent sign in them.
+-	**0.21** -- 27 Dec 2007
+	- 	Fix for combined strong and emphasis tags
+-	**0.20** -- 13 Oct 2007
+	-	Fix for < as well in image titles, now matches Dingus behavior
+-	**0.19** -- 28 Sep 2007
+	-	Fix for quotation marks " and ampersands & in link and image titles.
+-	**0.18** -- 28 Jul 2007
+	-	Does not crash on unmatched tags (behaves like standard markdown)
+-	**0.17** -- 12 Apr 2007
+	-	Fix for links with %20 in them.
+-	**0.16** -- 12 Apr 2007
+	-	Do not require arg global to exist.
+-	**0.15** -- 28 Aug 2006
+	-	Better handling of links with underscores in them.
+-	**0.14** -- 22 Aug 2006
+	-	Bug for *`foo()`*
+-	**0.13** -- 12 Aug 2006
+	-	Added -l option for including stylesheet inline in document.
+	-	Fixed bug in -s flag.
+	-	Fixed emphasis bug.
+-	**0.12** -- 15 May 2006
+	-	Fixed several bugs to comply with MarkdownTest 1.0 
+-	**0.11** -- 12 May 2006
+	-	Fixed bug for escaping `*` and `_` inside code spans.
+	-	Added license terms.
+	-	Changed join() to table.concat().
+-	**0.10** -- 3 May 2006
+	-	Initial public release.
+
+// Niklas
+]]
+
+
+-- Set up a table for holding local functions to avoid polluting the global namespace
+local M = {}
+local MT = {__index = _G}
+setmetatable(M, MT)
+setfenv(1, M)
+
+----------------------------------------------------------------------
+-- Utility functions
+----------------------------------------------------------------------
+
+-- Locks table t from changes, writes an error if someone attempts to change the table.
+-- This is useful for detecting variables that have "accidently" been made global. Something
+-- I tend to do all too much.
+function lock(t)
+	function lock_new_index(t, k, v)
+		error("module has been locked -- " .. k .. " must be declared local", 2)
+	end
+
+	local mt = {__newindex = lock_new_index}
+	if getmetatable(t) then mt.__index = getmetatable(t).__index end
+	setmetatable(t, mt)
+end
+
+-- Returns the result of mapping the values in table t through the function f
+function map(t, f)
+	local out = {}
+	for k,v in pairs(t) do out[k] = f(v,k) end
+	return out
+end
+
+-- The identity function, useful as a placeholder.
+function identity(text) return text end
+
+-- Functional style if statement. (NOTE: no short circuit evaluation)
+function iff(t, a, b) if t then return a else return b end end
+
+-- Splits the text into an array of separate lines.
+function split(text, sep)
+	sep = sep or "\n"
+	local lines = {}
+	local pos = 1
+	while true do
+		local b,e = text:find(sep, pos)
+		if not b then table.insert(lines, text:sub(pos)) break end
+		table.insert(lines, text:sub(pos, b-1))
+		pos = e + 1
+	end
+	return lines
+end
+
+-- Converts tabs to spaces
+function detab(text)
+	local tab_width = 4
+	local function rep(match)
+		local spaces = -match:len()
+		while spaces<1 do spaces = spaces + tab_width end
+		return match .. string.rep(" ", spaces)
+	end
+	text = text:gsub("([^\n]-)\t", rep)
+	return text
+end
+
+-- Applies string.find for every pattern in the list and returns the first match
+function find_first(s, patterns, index)
+	local res = {}
+	for _,p in ipairs(patterns) do
+		local match = {s:find(p, index)}
+		if #match>0 and (#res==0 or match[1] < res[1]) then res = match end
+	end
+	return unpack(res)
+end
+
+-- If a replacement array is specified, the range [start, stop] in the array is replaced
+-- with the replacement array and the resulting array is returned. Without a replacement
+-- array the section of the array between start and stop is returned.
+function splice(array, start, stop, replacement)
+	if replacement then
+		local n = stop - start + 1
+		while n > 0 do
+			table.remove(array, start)
+			n = n - 1
+		end
+		for i,v in ipairs(replacement) do
+			table.insert(array, start, v)
+		end
+		return array
+	else
+		local res = {}
+		for i = start,stop do
+			table.insert(res, array[i])
+		end
+		return res
+	end
+end
+
+-- Outdents the text one step.
+function outdent(text)
+	text = "\n" .. text
+	text = text:gsub("\n  ? ? ?", "\n")
+	text = text:sub(2)
+	return text
+end
+
+-- Indents the text one step.
+function indent(text)
+	text = text:gsub("\n", "\n    ")
+	return text
+end
+
+-- Does a simple tokenization of html data. Returns the data as a list of tokens. 
+-- Each token is a table with a type field (which is either "tag" or "text") and
+-- a text field (which contains the original token data).
+function tokenize_html(html)
+	local tokens = {}
+	local pos = 1
+	while true do
+		local start = find_first(html, {"", start)
+		elseif html:match("^<%?", start) then
+			_,stop = html:find("?>", start)
+		else
+			_,stop = html:find("%b<>", start)
+		end
+		if not stop then
+			-- error("Could not match html tag " .. html:sub(start,start+30)) 
+		 	table.insert(tokens, {type="text", text=html:sub(start, start)})
+			pos = start + 1
+		else
+			table.insert(tokens, {type="tag", text=html:sub(start, stop)})
+			pos = stop + 1
+		end
+	end
+	return tokens
+end
+
+----------------------------------------------------------------------
+-- Hash
+----------------------------------------------------------------------
+
+-- This is used to "hash" data into alphanumeric strings that are unique
+-- in the document. (Note that this is not cryptographic hash, the hash
+-- function is not one-way.) The hash procedure is used to protect parts
+-- of the document from further processing.
+
+local HASH = {
+	-- Has the hash been inited.
+	inited = false,
+	
+	-- The unique string prepended to all hash values. This is to ensure
+	-- that hash values do not accidently coincide with an actual existing
+	-- string in the document.
+	identifier = "",
+	
+	-- Counter that counts up for each new hash instance.
+	counter = 0,
+	
+	-- Hash table.
+	table = {}
+}
+
+-- Inits hashing. Creates a hash_identifier that doesn't occur anywhere
+-- in the text.
+function init_hash(text)
+	HASH.inited = true
+	HASH.identifier = ""
+	HASH.counter = 0
+	HASH.table = {}
+	
+	local s = "HASH"
+	local counter = 0
+	local id
+	while true do
+		id  = s .. counter
+		if not text:find(id, 1, true) then break end
+		counter = counter + 1
+	end
+	HASH.identifier = id
+end
+
+-- Returns the hashed value for s.
+function hash(s)
+	assert(HASH.inited)
+	if not HASH.table[s] then
+		HASH.counter = HASH.counter + 1
+		local id = HASH.identifier .. HASH.counter .. "X"
+		HASH.table[s] = id
+	end
+	return HASH.table[s]
+end
+
+----------------------------------------------------------------------
+-- Protection
+----------------------------------------------------------------------
+
+-- The protection module is used to "protect" parts of a document
+-- so that they are not modified by subsequent processing steps. 
+-- Protected parts are saved in a table for later unprotection
+
+-- Protection data
+local PD = {
+	-- Saved blocks that have been converted
+	blocks = {},
+
+	-- Block level tags that will be protected
+	tags = {"p", "div", "h1", "h2", "h3", "h4", "h5", "h6", "blockquote",
+	"pre", "table", "dl", "ol", "ul", "script", "noscript", "form", "fieldset",
+	"iframe", "math", "ins", "del"}
+}
+
+-- Pattern for matching a block tag that begins and ends in the leftmost
+-- column and may contain indented subtags, i.e.
+-- 
+-- A nested block. +--
+-- Nested data. +--
+--
+function block_pattern(tag) + return "\n<" .. tag .. ".-\n[ \t]*\n" +end + +-- Pattern for matching a block tag that begins and ends with a newline +function line_pattern(tag) + return "\n<" .. tag .. ".-[ \t]*\n" +end + +-- Protects the range of characters from start to stop in the text and +-- returns the protected string. +function protect_range(text, start, stop) + local s = text:sub(start, stop) + local h = hash(s) + PD.blocks[h] = s + text = text:sub(1,start) .. h .. text:sub(stop) + return text +end + +-- Protect every part of the text that matches any of the patterns. The first +-- matching pattern is protected first, etc. +function protect_matches(text, patterns) + while true do + local start, stop = find_first(text, patterns) + if not start then break end + text = protect_range(text, start, stop) + end + return text +end + +-- Protects blocklevel tags in the specified text +function protect(text) + -- First protect potentially nested block tags + text = protect_matches(text, map(PD.tags, block_pattern)) + -- Then protect block tags at the line level. + text = protect_matches(text, map(PD.tags, line_pattern)) + -- Protect
and comment tags + text = protect_matches(text, {"\n]->[ \t]*\n"}) + text = protect_matches(text, {"\n[ \t]*\n"}) + return text +end + +-- Returns true if the string s is a hash resulting from protection +function is_protected(s) + return PD.blocks[s] +end + +-- Unprotects the specified text by expanding all the nonces +function unprotect(text) + for k,v in pairs(PD.blocks) do + v = v:gsub("%%", "%%%%") + text = text:gsub(k, v) + end + return text +end + + +---------------------------------------------------------------------- +-- Block transform +---------------------------------------------------------------------- + +-- The block transform functions transform the text on the block level. +-- They work with the text as an array of lines rather than as individual +-- characters. + +-- Returns true if the line is a ruler of (char) characters. +-- The line must contain at least three char characters and contain only spaces and +-- char characters. +function is_ruler_of(line, char) + if not line:match("^[ %" .. char .. "]*$") then return false end + if not line:match("%" .. char .. ".*%" .. char .. ".*%" .. char) then return false end + return true +end + +-- Identifies the block level formatting present in the line +function classify(line) + local info = {line = line, text = line} + + if line:match("^ ") then + info.type = "indented" + info.outdented = line:sub(5) + return info + end + + for _,c in ipairs({'*', '-', '_', '='}) do + if is_ruler_of(line, c) then + info.type = "ruler" + info.ruler_char = c + return info + end + end + + if line == "" then + info.type = "blank" + return info + end + + if line:match("^(#+)[ \t]*(.-)[ \t]*#*[ \t]*$") then + local m1, m2 = line:match("^(#+)[ \t]*(.-)[ \t]*#*[ \t]*$") + info.type = "header" + info.level = m1:len() + info.text = m2 + return info + end + + if line:match("^ ? ? ?(%d+)%.[ \t]+(.+)") then + local number, text = line:match("^ ? ? ?(%d+)%.[ \t]+(.+)") + info.type = "list_item" + info.list_type = "numeric" + info.number = 0 + number + info.text = text + return info + end + + if line:match("^ ? ? ?([%*%+%-])[ \t]+(.+)") then + local bullet, text = line:match("^ ? ? ?([%*%+%-])[ \t]+(.+)") + info.type = "list_item" + info.list_type = "bullet" + info.bullet = bullet + info.text= text + return info + end + + if line:match("^>[ \t]?(.*)") then + info.type = "blockquote" + info.text = line:match("^>[ \t]?(.*)") + return info + end + + if is_protected(line) then + info.type = "raw" + info.html = unprotect(line) + return info + end + + info.type = "normal" + return info +end + +-- Find headers constisting of a normal line followed by a ruler and converts them to +-- header entries. +function headers(array) + local i = 1 + while i <= #array - 1 do + if array[i].type == "normal" and array[i+1].type == "ruler" and + (array[i+1].ruler_char == "-" or array[i+1].ruler_char == "=") then + local info = {line = array[i].line} + info.text = info.line + info.type = "header" + info.level = iff(array[i+1].ruler_char == "=", 1, 2) + table.remove(array, i+1) + array[i] = info + end + i = i + 1 + end + return array +end + +-- Find list blocks and convert them to protected data blocks +function lists(array, sublist) + local function process_list(arr) + local function any_blanks(arr) + for i = 1, #arr do + if arr[i].type == "blank" then return true end + end + return false + end + + local function split_list_items(arr) + local acc = {arr[1]} + local res = {} + for i=2,#arr do + if arr[i].type == "list_item" then + table.insert(res, acc) + acc = {arr[i]} + else + table.insert(acc, arr[i]) + end + end + table.insert(res, acc) + return res + end + + local function process_list_item(lines, block) + while lines[#lines].type == "blank" do + table.remove(lines) + end + + local itemtext = lines[1].text + for i=2,#lines do + itemtext = itemtext .. "\n" .. outdent(lines[i].line) + end + if block then + itemtext = block_transform(itemtext, true) + if not itemtext:find("
") then itemtext = indent(itemtext) end
+				return "    
  • " .. itemtext .. "
  • " + else + local lines = split(itemtext) + lines = map(lines, classify) + lines = lists(lines, true) + lines = blocks_to_html(lines, true) + itemtext = table.concat(lines, "\n") + if not itemtext:find("
    ") then itemtext = indent(itemtext) end
    +				return "    
  • " .. itemtext .. "
  • " + end + end + + local block_list = any_blanks(arr) + local items = split_list_items(arr) + local out = "" + for _, item in ipairs(items) do + out = out .. process_list_item(item, block_list) .. "\n" + end + if arr[1].list_type == "numeric" then + return "
      \n" .. out .. "
    " + else + return "
      \n" .. out .. "
    " + end + end + + -- Finds the range of lines composing the first list in the array. A list + -- starts with (^ list_item) or (blank list_item) and ends with + -- (blank* $) or (blank normal). + -- + -- A sublist can start with just (list_item) does not need a blank... + local function find_list(array, sublist) + local function find_list_start(array, sublist) + if array[1].type == "list_item" then return 1 end + if sublist then + for i = 1,#array do + if array[i].type == "list_item" then return i end + end + else + for i = 1, #array-1 do + if array[i].type == "blank" and array[i+1].type == "list_item" then + return i+1 + end + end + end + return nil + end + local function find_list_end(array, start) + local pos = #array + for i = start, #array-1 do + if array[i].type == "blank" and array[i+1].type ~= "list_item" + and array[i+1].type ~= "indented" and array[i+1].type ~= "blank" then + pos = i-1 + break + end + end + while pos > start and array[pos].type == "blank" do + pos = pos - 1 + end + return pos + end + + local start = find_list_start(array, sublist) + if not start then return nil end + return start, find_list_end(array, start) + end + + while true do + local start, stop = find_list(array, sublist) + if not start then break end + local text = process_list(splice(array, start, stop)) + local info = { + line = text, + type = "raw", + html = text + } + array = splice(array, start, stop, {info}) + end + + -- Convert any remaining list items to normal + for _,line in ipairs(array) do + if line.type == "list_item" then line.type = "normal" end + end + + return array +end + +-- Find and convert blockquote markers. +function blockquotes(lines) + local function find_blockquote(lines) + local start + for i,line in ipairs(lines) do + if line.type == "blockquote" then + start = i + break + end + end + if not start then return nil end + + local stop = #lines + for i = start+1, #lines do + if lines[i].type == "blank" or lines[i].type == "blockquote" then + elseif lines[i].type == "normal" then + if lines[i-1].type == "blank" then stop = i-1 break end + else + stop = i-1 break + end + end + while lines[stop].type == "blank" do stop = stop - 1 end + return start, stop + end + + local function process_blockquote(lines) + local raw = lines[1].text + for i = 2,#lines do + raw = raw .. "\n" .. lines[i].text + end + local bt = block_transform(raw) + if not bt:find("
    ") then bt = indent(bt) end
    +		return "
    \n " .. bt .. + "\n
    " + end + + while true do + local start, stop = find_blockquote(lines) + if not start then break end + local text = process_blockquote(splice(lines, start, stop)) + local info = { + line = text, + type = "raw", + html = text + } + lines = splice(lines, start, stop, {info}) + end + return lines +end + +-- Find and convert codeblocks. +function codeblocks(lines) + local function find_codeblock(lines) + local start + for i,line in ipairs(lines) do + if line.type == "indented" then start = i break end + end + if not start then return nil end + + local stop = #lines + for i = start+1, #lines do + if lines[i].type ~= "indented" and lines[i].type ~= "blank" then + stop = i-1 + break + end + end + while lines[stop].type == "blank" do stop = stop - 1 end + return start, stop + end + + local function process_codeblock(lines) + local raw = detab(encode_code(outdent(lines[1].line))) + for i = 2,#lines do + raw = raw .. "\n" .. detab(encode_code(outdent(lines[i].line))) + end + return "
    " .. raw .. "\n
    " + end + + while true do + local start, stop = find_codeblock(lines) + if not start then break end + local text = process_codeblock(splice(lines, start, stop)) + local info = { + line = text, + type = "raw", + html = text + } + lines = splice(lines, start, stop, {info}) + end + return lines +end + +-- Convert lines to html code +function blocks_to_html(lines, no_paragraphs) + local out = {} + local i = 1 + while i <= #lines do + local line = lines[i] + if line.type == "ruler" then + table.insert(out, "
    ") + elseif line.type == "raw" then + table.insert(out, line.html) + elseif line.type == "normal" then + local s = line.line + + while i+1 <= #lines and lines[i+1].type == "normal" do + i = i + 1 + s = s .. "\n" .. lines[i].line + end + + if no_paragraphs then + table.insert(out, span_transform(s)) + else + table.insert(out, "

    " .. span_transform(s) .. "

    ") + end + elseif line.type == "header" then + local s = "" .. span_transform(line.text) .. "" + table.insert(out, s) + else + table.insert(out, line.line) + end + i = i + 1 + end + return out +end + +-- Perform all the block level transforms +function block_transform(text, sublist) + local lines = split(text) + lines = map(lines, classify) + lines = headers(lines) + lines = lists(lines, sublist) + lines = codeblocks(lines) + lines = blockquotes(lines) + lines = blocks_to_html(lines) + local text = table.concat(lines, "\n") + return text +end + +-- Debug function for printing a line array to see the result +-- of partial transforms. +function print_lines(lines) + for i, line in ipairs(lines) do + print(i, line.type, line.text or line.line) + end +end + +---------------------------------------------------------------------- +-- Span transform +---------------------------------------------------------------------- + +-- Functions for transforming the text at the span level. + +-- These characters may need to be escaped because they have a special +-- meaning in markdown. +escape_chars = "'\\`*_{}[]()>#+-.!'" +escape_table = {} + +function init_escape_table() + escape_table = {} + for i = 1,#escape_chars do + local c = escape_chars:sub(i,i) + escape_table[c] = hash(c) + end +end + +-- Adds a new escape to the escape table. +function add_escape(text) + if not escape_table[text] then + escape_table[text] = hash(text) + end + return escape_table[text] +end + +-- Escape characters that should not be disturbed by markdown. +function escape_special_chars(text) + local tokens = tokenize_html(text) + + local out = "" + for _, token in ipairs(tokens) do + local t = token.text + if token.type == "tag" then + -- In tags, encode * and _ so they don't conflict with their use in markdown. + t = t:gsub("%*", escape_table["*"]) + t = t:gsub("%_", escape_table["_"]) + else + t = encode_backslash_escapes(t) + end + out = out .. t + end + return out +end + +-- Encode backspace-escaped characters in the markdown source. +function encode_backslash_escapes(t) + for i=1,escape_chars:len() do + local c = escape_chars:sub(i,i) + t = t:gsub("\\%" .. c, escape_table[c]) + end + return t +end + +-- Unescape characters that have been encoded. +function unescape_special_chars(t) + local tin = t + for k,v in pairs(escape_table) do + k = k:gsub("%%", "%%%%") + t = t:gsub(v,k) + end + if t ~= tin then t = unescape_special_chars(t) end + return t +end + +-- Encode/escape certain characters inside Markdown code runs. +-- The point is that in code, these characters are literals, +-- and lose their special Markdown meanings. +function encode_code(s) + s = s:gsub("%&", "&") + s = s:gsub("<", "<") + s = s:gsub(">", ">") + for k,v in pairs(escape_table) do + s = s:gsub("%"..k, v) + end + return s +end + +-- Handle backtick blocks. +function code_spans(s) + s = s:gsub("\\\\", escape_table["\\"]) + s = s:gsub("\\`", escape_table["`"]) + + local pos = 1 + while true do + local start, stop = s:find("`+", pos) + if not start then return s end + local count = stop - start + 1 + -- Find a matching numbert of backticks + local estart, estop = s:find(string.rep("`", count), stop+1) + local brstart = s:find("\n", stop+1) + if estart and (not brstart or estart < brstart) then + local code = s:sub(stop+1, estart-1) + code = code:gsub("^[ \t]+", "") + code = code:gsub("[ \t]+$", "") + code = code:gsub(escape_table["\\"], escape_table["\\"] .. escape_table["\\"]) + code = code:gsub(escape_table["`"], escape_table["\\"] .. escape_table["`"]) + code = "" .. encode_code(code) .. "" + code = add_escape(code) + s = s:sub(1, start-1) .. code .. s:sub(estop+1) + pos = start + code:len() + else + pos = stop + 1 + end + end + return s +end + +-- Encode alt text... enodes &, and ". +function encode_alt(s) + if not s then return s end + s = s:gsub('&', '&') + s = s:gsub('"', '"') + s = s:gsub('<', '<') + return s +end + +-- Handle image references +function images(text) + local function reference_link(alt, id) + alt = encode_alt(alt:match("%b[]"):sub(2,-2)) + id = id:match("%[(.*)%]"):lower() + if id == "" then id = text:lower() end + link_database[id] = link_database[id] or {} + if not link_database[id].url then return nil end + local url = link_database[id].url or id + url = encode_alt(url) + local title = encode_alt(link_database[id].title) + if title then title = " title=\"" .. title .. "\"" else title = "" end + return add_escape ('' .. alt .. '") + end + + local function inline_link(alt, link) + alt = encode_alt(alt:match("%b[]"):sub(2,-2)) + local url, title = link:match("%(?[ \t]*['\"](.+)['\"]") + url = url or link:match("%(?%)") + url = encode_alt(url) + title = encode_alt(title) + if title then + return add_escape('' .. alt .. '') + else + return add_escape('' .. alt .. '') + end + end + + text = text:gsub("!(%b[])[ \t]*\n?[ \t]*(%b[])", reference_link) + text = text:gsub("!(%b[])(%b())", inline_link) + return text +end + +-- Handle anchor references +function anchors(text) + local function reference_link(text, id) + text = text:match("%b[]"):sub(2,-2) + id = id:match("%b[]"):sub(2,-2):lower() + if id == "" then id = text:lower() end + link_database[id] = link_database[id] or {} + if not link_database[id].url then return nil end + local url = link_database[id].url or id + url = encode_alt(url) + local title = encode_alt(link_database[id].title) + if title then title = " title=\"" .. title .. "\"" else title = "" end + return add_escape("") .. text .. add_escape("") + end + + local function inline_link(text, link) + text = text:match("%b[]"):sub(2,-2) + local url, title = link:match("%(?[ \t]*['\"](.+)['\"]") + title = encode_alt(title) + url = url or link:match("%(?%)") or "" + url = encode_alt(url) + if title then + return add_escape("") .. text .. "" + else + return add_escape("") .. text .. add_escape("") + end + end + + text = text:gsub("(%b[])[ \t]*\n?[ \t]*(%b[])", reference_link) + text = text:gsub("(%b[])(%b())", inline_link) + return text +end + +-- Handle auto links, i.e. . +function auto_links(text) + local function link(s) + return add_escape("") .. s .. "" + end + -- Encode chars as a mix of dec and hex entitites to (perhaps) fool + -- spambots. + local function encode_email_address(s) + -- Use a deterministic encoding to make unit testing possible. + -- Code 45% hex, 45% dec, 10% plain. + local hex = {code = function(c) return "&#x" .. string.format("%x", c:byte()) .. ";" end, count = 1, rate = 0.45} + local dec = {code = function(c) return "&#" .. c:byte() .. ";" end, count = 0, rate = 0.45} + local plain = {code = function(c) return c end, count = 0, rate = 0.1} + local codes = {hex, dec, plain} + local function swap(t,k1,k2) local temp = t[k2] t[k2] = t[k1] t[k1] = temp end + + local out = "" + for i = 1,s:len() do + for _,code in ipairs(codes) do code.count = code.count + code.rate end + if codes[1].count < codes[2].count then swap(codes,1,2) end + if codes[2].count < codes[3].count then swap(codes,2,3) end + if codes[1].count < codes[2].count then swap(codes,1,2) end + + local code = codes[1] + local c = s:sub(i,i) + -- Force encoding of "@" to make email address more invisible. + if c == "@" and code == plain then code = codes[2] end + out = out .. code.code(c) + code.count = code.count - 1 + end + return out + end + local function mail(s) + s = unescape_special_chars(s) + local address = encode_email_address("mailto:" .. s) + local text = encode_email_address(s) + return add_escape("") .. text .. "" + end + -- links + text = text:gsub("<(https?:[^'\">%s]+)>", link) + text = text:gsub("<(ftp:[^'\">%s]+)>", link) + + -- mail + text = text:gsub("%s]+)>", mail) + text = text:gsub("<([-.%w]+%@[-.%w]+)>", mail) + return text +end + +-- Encode free standing amps (&) and angles (<)... note that this does not +-- encode free >. +function amps_and_angles(s) + -- encode amps not part of &..; expression + local pos = 1 + while true do + local amp = s:find("&", pos) + if not amp then break end + local semi = s:find(";", amp+1) + local stop = s:find("[ \t\n&]", amp+1) + if not semi or (stop and stop < semi) or (semi - amp) > 15 then + s = s:sub(1,amp-1) .. "&" .. s:sub(amp+1) + pos = amp+1 + else + pos = amp+1 + end + end + + -- encode naked <'s + s = s:gsub("<([^a-zA-Z/?$!])", "<%1") + s = s:gsub("<$", "<") + + -- what about >, nothing done in the original markdown source to handle them + return s +end + +-- Handles emphasis markers (* and _) in the text. +function emphasis(text) + for _, s in ipairs {"%*%*", "%_%_"} do + text = text:gsub(s .. "([^%s][%*%_]?)" .. s, "%1") + text = text:gsub(s .. "([^%s][^<>]-[^%s][%*%_]?)" .. s, "%1") + end + for _, s in ipairs {"%*", "%_"} do + text = text:gsub(s .. "([^%s_])" .. s, "%1") + text = text:gsub(s .. "([^%s_])" .. s, "%1") + text = text:gsub(s .. "([^%s_][^<>_]-[^%s_])" .. s, "%1") + text = text:gsub(s .. "([^<>_]-[^<>_]-[^<>_]-)" .. s, "%1") + end + return text +end + +-- Handles line break markers in the text. +function line_breaks(text) + return text:gsub(" +\n", "
    \n") +end + +-- Perform all span level transforms. +function span_transform(text) + text = code_spans(text) + text = escape_special_chars(text) + text = images(text) + text = anchors(text) + text = auto_links(text) + text = amps_and_angles(text) + text = emphasis(text) + text = line_breaks(text) + return text +end + +---------------------------------------------------------------------- +-- Markdown +---------------------------------------------------------------------- + +-- Cleanup the text by normalizing some possible variations to make further +-- processing easier. +function cleanup(text) + -- Standardize line endings + text = text:gsub("\r\n", "\n") -- DOS to UNIX + text = text:gsub("\r", "\n") -- Mac to UNIX + + -- Convert all tabs to spaces + text = detab(text) + + -- Strip lines with only spaces and tabs + while true do + local subs + text, subs = text:gsub("\n[ \t]+\n", "\n\n") + if subs == 0 then break end + end + + return "\n" .. text .. "\n" +end + +-- Strips link definitions from the text and stores the data in a lookup table. +function strip_link_definitions(text) + local linkdb = {} + + local function link_def(id, url, title) + id = id:match("%[(.+)%]"):lower() + linkdb[id] = linkdb[id] or {} + linkdb[id].url = url or linkdb[id].url + linkdb[id].title = title or linkdb[id].title + return "" + end + + local def_no_title = "\n ? ? ?(%b[]):[ \t]*\n?[ \t]*]+)>?[ \t]*" + local def_title1 = def_no_title .. "[ \t]+\n?[ \t]*[\"'(]([^\n]+)[\"')][ \t]*" + local def_title2 = def_no_title .. "[ \t]*\n[ \t]*[\"'(]([^\n]+)[\"')][ \t]*" + local def_title3 = def_no_title .. "[ \t]*\n?[ \t]+[\"'(]([^\n]+)[\"')][ \t]*" + + text = text:gsub(def_title1, link_def) + text = text:gsub(def_title2, link_def) + text = text:gsub(def_title3, link_def) + text = text:gsub(def_no_title, link_def) + return text, linkdb +end + +link_database = {} + +-- Main markdown processing function +function markdown(text) + init_hash(text) + init_escape_table() + + text = cleanup(text) + text = protect(text) + text, link_database = strip_link_definitions(text) + text = block_transform(text) + text = unescape_special_chars(text) + return text +end + +---------------------------------------------------------------------- +-- End of module +---------------------------------------------------------------------- + +setfenv(1, _G) +M.lock(M) + +-- Expose markdown function to the world +markdown = M.markdown + +-- Class for parsing command-line options +local OptionParser = {} +OptionParser.__index = OptionParser + +-- Creates a new option parser +function OptionParser:new() + local o = {short = {}, long = {}} + setmetatable(o, self) + return o +end + +-- Calls f() whenever a flag with specified short and long name is encountered +function OptionParser:flag(short, long, f) + local info = {type = "flag", f = f} + if short then self.short[short] = info end + if long then self.long[long] = info end +end + +-- Calls f(param) whenever a parameter flag with specified short and long name is encountered +function OptionParser:param(short, long, f) + local info = {type = "param", f = f} + if short then self.short[short] = info end + if long then self.long[long] = info end +end + +-- Calls f(v) for each non-flag argument +function OptionParser:arg(f) + self.arg = f +end + +-- Runs the option parser for the specified set of arguments. Returns true if all arguments +-- where successfully parsed and false otherwise. +function OptionParser:run(args) + local pos = 1 + while pos <= #args do + local arg = args[pos] + if arg == "--" then + for i=pos+1,#args do + if self.arg then self.arg(args[i]) end + return true + end + end + if arg:match("^%-%-") then + local info = self.long[arg:sub(3)] + if not info then print("Unknown flag: " .. arg) return false end + if info.type == "flag" then + info.f() + pos = pos + 1 + else + param = args[pos+1] + if not param then print("No parameter for flag: " .. arg) return false end + info.f(param) + pos = pos+2 + end + elseif arg:match("^%-") then + for i=2,arg:len() do + local c = arg:sub(i,i) + local info = self.short[c] + if not info then print("Unknown flag: -" .. c) return false end + if info.type == "flag" then + info.f() + else + if i == arg:len() then + param = args[pos+1] + if not param then print("No parameter for flag: -" .. c) return false end + info.f(param) + pos = pos + 1 + else + param = arg:sub(i+1) + info.f(param) + end + break + end + end + pos = pos + 1 + else + if self.arg then self.arg(arg) end + pos = pos + 1 + end + end + return true +end + +-- Handles the case when markdown is run from the command line +local function run_command_line(arg) + -- Generate output for input s given options + local function run(s, options) + s = markdown(s) + if not options.wrap_header then return s end + local header = "" + if options.header then + local f = io.open(options.header) or error("Could not open file: " .. options.header) + header = f:read("*a") + f:close() + else + header = [[ + + + + + TITLE + + + +]] + local title = options.title or s:match("

    (.-)

    ") or s:match("

    (.-)

    ") or + s:match("

    (.-)

    ") or "Untitled" + header = header:gsub("TITLE", title) + if options.inline_style then + local style = "" + local f = io.open(options.stylesheet) + if f then + style = f:read("*a") f:close() + else + error("Could not include style sheet " .. options.stylesheet .. ": File not found") + end + header = header:gsub('', + "") + else + header = header:gsub("STYLESHEET", options.stylesheet) + end + header = header:gsub("CHARSET", options.charset) + end + local footer = "" + if options.footer then + local f = io.open(options.footer) or error("Could not open file: " .. options.footer) + footer = f:read("*a") + f:close() + end + return header .. s .. footer + end + + -- Generate output path name from input path name given options. + local function outpath(path, options) + if options.append then return path .. ".html" end + local m = path:match("^(.+%.html)[^/\\]+$") if m then return m end + m = path:match("^(.+%.)[^/\\]*$") if m and path ~= m .. "html" then return m .. "html" end + return path .. ".html" + end + + -- Default commandline options + local options = { + wrap_header = true, + header = nil, + footer = nil, + charset = "utf-8", + title = nil, + stylesheet = "default.css", + inline_style = false + } + local help = [[ +Usage: markdown.lua [OPTION] [FILE] +Runs the markdown text markup to HTML converter on each file specified on the +command line. If no files are specified, runs on standard input. + +No header: + -n, --no-wrap Don't wrap the output in ... tags. +Custom header: + -e, --header FILE Use content of FILE for header. + -f, --footer FILE Use content of FILE for footer. +Generated header: + -c, --charset SET Specifies charset (default utf-8). + -i, --title TITLE Specifies title (default from first

    tag). + -s, --style STYLE Specifies style sheet file (default default.css). + -l, --inline-style Include the style sheet file inline in the header. +Generated files: + -a, --append Append .html extension (instead of replacing). +Other options: + -h, --help Print this help text. + -t, --test Run the unit tests. +]] + + local run_stdin = true + local op = OptionParser:new() + op:flag("n", "no-wrap", function () options.wrap_header = false end) + op:param("e", "header", function (x) options.header = x end) + op:param("f", "footer", function (x) options.footer = x end) + op:param("c", "charset", function (x) options.charset = x end) + op:param("i", "title", function(x) options.title = x end) + op:param("s", "style", function(x) options.stylesheet = x end) + op:flag("l", "inline-style", function(x) options.inline_style = true end) + op:flag("a", "append", function() options.append = true end) + op:flag("t", "test", function() + local n = arg[0]:gsub("markdown.lua", "markdown-tests.lua") + local f = io.open(n) + if f then + f:close() dofile(n) + else + error("Cannot find markdown-tests.lua") + end + run_stdin = false + end) + op:flag("h", "help", function() print(help) run_stdin = false end) + op:arg(function(path) + local file = io.open(path) or error("Could not open file: " .. path) + local s = file:read("*a") + file:close() + s = run(s, options) + file = io.open(outpath(path, options), "w") or error("Could not open output file: " .. outpath(path, options)) + file:write(s) + file:close() + run_stdin = false + end + ) + + if not op:run(arg) then + print(help) + run_stdin = false + end + + if run_stdin then + local s = io.read("*a") + s = run(s, options) + io.write(s) + end +end + +-- If we are being run from the command-line, act accordingly +if arg and arg[0]:find("markdown%.lua$") then + run_command_line(arg) +else + return markdown +end \ No newline at end of file