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diff --git a/docs/markdown.lua b/docs/markdown.lua new file mode 100644 index 0000000..f23954f --- /dev/null +++ b/docs/markdown.lua @@ -0,0 +1,1388 @@ +#!/usr/bin/env lua
+
+--[[
+# markdown.lua -- version 0.32
+
+<http://www.frykholm.se/files/markdown.lua>
+
+**Author:** Niklas Frykholm, <niklas@frykholm.se>
+**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 <http://daringfireball.net/projects/markdown>.
+
+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 <pre> 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 <http://six.pairlist.net/pipermail/markdown-discuss/2004-December/000909.html>
+- **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, {"<!%-%-", "<[a-z/!$]", "<%?"}, pos)
+ if not start then
+ table.insert(tokens, {type="text", text=html:sub(pos)})
+ break
+ end
+ if start ~= pos then table.insert(tokens, {type="text", text = html:sub(pos, start-1)}) end
+
+ local _, stop
+ if html:match("^<!%-%-", start) then
+ _,stop = html:find("%-%->", 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.
+-- <div>
+-- A nested block.
+-- <div>
+-- Nested data.
+-- </div>
+-- </div>
+function block_pattern(tag)
+ return "\n<" .. tag .. ".-\n</" .. tag .. ">[ \t]*\n"
+end
+
+-- Pattern for matching a block tag that begins and ends with a newline
+function line_pattern(tag)
+ return "\n<" .. tag .. ".-</" .. 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 <hr> and comment tags
+ text = protect_matches(text, {"\n<hr[^>]->[ \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("<pre>") then itemtext = indent(itemtext) end
+ return " <li>" .. itemtext .. "</li>"
+ 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("<pre>") then itemtext = indent(itemtext) end
+ return " <li>" .. itemtext .. "</li>"
+ 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 "<ol>\n" .. out .. "</ol>"
+ else
+ return "<ul>\n" .. out .. "</ul>"
+ 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("<pre>") then bt = indent(bt) end
+ return "<blockquote>\n " .. bt ..
+ "\n</blockquote>"
+ 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 "<pre><code>" .. raw .. "\n</code></pre>"
+ 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
+
+local idcount = 1
+local list_of_headers = {}
+local first_header
+
+-- 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, "<hr/>")
+ 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, "<p>" .. span_transform(s) .. "</p>")
+ end
+ elseif line.type == "header" then
+ local txt = span_transform(line.text)
+ local id = "T" .. idcount
+ local s = "<h" .. line.level .. ' id="'.. id .. '">' .. txt .. "</h" .. line.level .. ">"
+ if not first_header then
+ first_header = {line=s,text=txt}
+ else
+ table.insert(out, s)
+ table.insert(list_of_headers, {level=line.level,text=txt,id=id})
+ end
+ idcount = idcount + 1
+ 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 = "<code>" .. encode_code(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 ('<img src="' .. url .. '" alt="' .. alt .. '"' .. title .. "/>")
+ 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('<img src="' .. url .. '" alt="' .. alt .. '" title="' .. title .. '"/>')
+ else
+ return add_escape('<img src="' .. url .. '" alt="' .. 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("<a href=\"" .. url .. "\"" .. title .. ">") .. text .. add_escape("</a>")
+ 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("<a href=\"" .. url .. "\" title=\"" .. title .. "\">") .. text .. "</a>"
+ else
+ return add_escape("<a href=\"" .. url .. "\">") .. text .. add_escape("</a>")
+ 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. <http://www.google.com/>.
+function auto_links(text)
+ local function link(s)
+ return add_escape("<a href=\"" .. s .. "\">") .. s .. "</a>"
+ 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("<a href=\"" .. address .. "\">") .. text .. "</a>"
+ end
+ -- links
+ text = text:gsub("<(https?:[^'\">%s]+)>", link)
+ text = text:gsub("<(ftp:[^'\">%s]+)>", link)
+
+ -- mail
+ text = text:gsub("<mailto:([^'\">%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, "<strong>%1</strong>")
+ text = text:gsub(s .. "([^%s][^<>]-[^%s][%*%_]?)" .. s, "<strong>%1</strong>")
+ end
+ for _, s in ipairs {"%*", "%_"} do
+ text = text:gsub(s .. "([^%s_])" .. s, "<em>%1</em>")
+ text = text:gsub(s .. "(<strong>[^%s_]</strong>)" .. s, "<em>%1</em>")
+ text = text:gsub(s .. "([^%s_][^<>_]-[^%s_])" .. s, "<em>%1</em>")
+ text = text:gsub(s .. "([^<>_]-<strong>[^<>_]-</strong>[^<>_]-)" .. s, "<em>%1</em>")
+ end
+ return text
+end
+
+-- Handles line break markers in the text.
+function line_breaks(text)
+ return text:gsub(" +\n", " <br/>\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]*<?([^%s>]+)>?[ \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 = [[
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html>
+<head>
+ <meta http-equiv="content-type" content="text/html; charset=CHARSET" />
+ <title>TITLE</title>
+ <link rel="stylesheet" type="text/css" href="STYLESHEET" />
+</head>
+<body>
+]]
+ local title = options.title or (first_header and first_header.text) 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('<link rel="stylesheet" type="text/css" href="STYLESHEET" />',
+ "<style type=\"text/css\"><!--\n" .. style .. "\n--></style>")
+ else
+ header = header:gsub("STYLESHEET", options.stylesheet)
+ end
+ header = header:gsub("CHARSET", options.charset)
+ end
+ local footer = "</body></html>"
+ 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
+ if first_header then
+ header = header .. first_header.line ..'\n'
+ -- Build TOC if required!
+ local txt = ''
+ local indent = 0
+ local last_level
+ for i,h in ipairs(list_of_headers) do
+ if i > 1 then
+ local diff = h.level - last_level
+ if diff > 0 then indent = indent + 1
+ elseif diff < 0 then indent = indent - 1
+ end
+ end
+ txt = txt..string.rep('\t',indent)..'* ['..h.text..'](#'..h.id..')\n'
+ last_level = h.level
+ end
+ header = header .. markdown(txt)
+ 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 <html>... 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 <h1> 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
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