changeset
Update markdown; now Lua 5.3 compatible
Tue, 16 Jan 2018 17:02:22 +0000
- author
- Tuomo Valkonen <tuomov@iki.fi>
- date
- Tue, 16 Jan 2018 17:02:22 +0000
- changeset 8
- 836dac92eced
- parent 7
- 038275cd92ed
- child 9
- 751216807683
Update markdown; now Lua 5.3 compatible
| markdown.lua | file | annotate | diff | comparison | revisions |
--- a/markdown.lua Tue Jan 16 16:39:48 2018 +0000 +++ b/markdown.lua Tue Jan 16 17:02:22 2018 +0000 @@ -1,1359 +1,1212 @@ -#!/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 table.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 - --- 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 s = "<h" .. line.level .. ">" .. span_transform(line.text) .. "</h" .. line.level .. ">" - 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 = "<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 s:match("<h1>(.-)</h1>") or s:match("<h2>(.-)</h2>") or - s:match("<h3>(.-)</h3>") 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 - 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 \ No newline at end of file +#!/usr/bin/env lua + +---------------------------------------------------------------------- +-- Utility functions +---------------------------------------------------------------------- + +local unpack = table.unpack or unpack + +-- Returns the result of mapping the values in table t through the function f +local function map(t, f) + local out = {} + for k,v in pairs(t) do out[k] = f(v,k) end + return out +end + +-- Functional style if statement. (NOTE: no short circuit evaluation) +local function iff(t, a, b) if t then return a else return b end end + +-- Splits the text into an array of separate lines. +local 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 +local 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 +local 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. +local 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 _,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. +local function outdent(text) + text = "\n" .. text + text = text:gsub("\n ? ? ?", "\n") + text = text:sub(2) + return text +end + +-- Indents the text one step. +local 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). +local 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. +local 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. +local 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> +local 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 +local 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. +local 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. +local 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 +local 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 +local function is_protected(s) + return PD.blocks[s] +end + +-- Unprotects the specified text by expanding all the nonces +local 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. +local function is_ruler_of(line, char) + if not line:match("^[ %" .. char .. "]*$") then return false end + if not line:match("%" .. char .. ".*%" .. char .. ".*%" .. char) then return false end + return true +end + +-- Identifies the block level formatting present in the line +local function classify(line) + local info = {line = line, text = line} + + if line:match("^ ") then + info.type = "indented" + info.outdented = line:sub(5) + return info + end + + for _,c in ipairs({'*', '-', '_', '='}) do + if is_ruler_of(line, c) then + info.type = "ruler" + info.ruler_char = c + return info + end + end + + if line == "" then + info.type = "blank" + return info + end + + if line:match("^(#+)[ \t]*(.-)[ \t]*#*[ \t]*$") 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. +local 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 + +-- Forward declarations +local block_transform, span_transform, encode_code + +-- Convert lines to html code +local 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 s = "<h" .. line.level .. ">" .. span_transform(line.text) .. "</h" .. line.level .. ">" + table.insert(out, s) + else + table.insert(out, line.line) + end + i = i + 1 + end + return out +end + +-- Find list blocks and convert them to protected data blocks +local 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. +local 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. +local 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 + +-- 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 + +---------------------------------------------------------------------- +-- 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. +local escape_chars = "'\\`*_{}[]()>#+-.!'" +local escape_table = {} + +local 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. +local function add_escape(text) + if not escape_table[text] then + escape_table[text] = hash(text) + end + return escape_table[text] +end + +-- Encode backspace-escaped characters in the markdown source. +local 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 + +-- Escape characters that should not be disturbed by markdown. +local 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 + +-- Unescape characters that have been encoded. +local 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. +local 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 ". +local function encode_alt(s) + if not s then return s end + s = s:gsub('&', '&') + s = s:gsub('"', '"') + s = s:gsub('<', '<') + return s +end + +-- Forward declaration for link_db as returned by strip_link_definitions. +local link_database + +-- Handle image references +local 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 +local 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/>. +local 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 >. +local 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. +local 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. +local 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. +local 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. +local 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 + +-- Main markdown processing function +local 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 +---------------------------------------------------------------------- + +-- For compatibility, set markdown function as a global +_G.markdown = 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 + local 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 + local param = args[pos+1] + if not param then print("No parameter for flag: -" .. c) return false end + info.f(param) + pos = pos + 1 + else + local 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 + +local function read_file(path, descr) + local file = io.open(path) or error("Could not open " .. descr .. " file: " .. path) + local contents = file:read("*a") or error("Could not read " .. descr .. " from " .. path) + file:close() + return contents +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 + header = read_file(options.header, "header") + 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 s:match("<h1>(.-)</h1>") or s:match("<h2>(.-)</h2>") or + s:match("<h3>(.-)</h3>") or "Untitled" + header = header:gsub("TITLE", title) + if options.inline_style then + local style = read_file(options.stylesheet, "style sheet") + 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 + footer = read_file(options.footer, "footer") + 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() 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() + package.loaded.markdown = markdown + 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 s = read_file(path, "input") + s = run(s, options) + local 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
