stevedonovan/prettify.lua

## prettify.lua
-- translate Markdown with code blocks into HTML
-- with syntax highlighting.
-- If article.md was the source, Lua was the language and we
-- wanted a preview:
-- lua prettify.lua article lua preview
-- Without the last argument it will just write out the HTML body.
-- Languages supported are 'lua', 'cpp', 'java' and 'go
-- Indented code blocks may begin with an explicit @lang name line;
-- if you do this then mark every code block explicitly
-- e.g
--    @lang lua
--    print "hello world"
--
-- (any line)
--
--   @lang go
--   fnt.Println("hello world"
--
-- Needs markdown.lua and Penlight.
-- Steve Donovan, 2011 MIT license.
require 'pl'
require 'markdown'

local tnext = lexer.skipws
local concat = table.concat

local escaped_chars = {
   ['&'] = '&amp;',
   ['<'] = '&lt;',
   ['>'] = '&gt;',
}
local escape_pat = '[&<>]'

local function escape(str)
   return (str:gsub(escape_pat,escaped_chars))
end

local function span(t,val)
   return ('<span class="%s">%s</span>'):format(t,val)
end

local spans = {keyword=true,number=true,string=true,comment=true}


local jkeywords = {
   final = true, extends = true, implements = true,
   interface = true, import = true, throws = true, null = true
}

local gkeywords = { byte=true,chan=true,complex64=true,
complex128=true,defer=true,func=true,fallthrough=true,
float32=true,float64=true,string=true,uint=true,uintptr=true,
uint8=true,uint16=true,uint32=true,uint64=true,
var=true,len=true,map=true,package=true,range=true,select=true,
type=true,interface=true,int8=true,int16=true,int32=true,
int64=true,['nil']=true,func=true
}

local function prettify (code,lang)
   local res = List()
   res:append '<pre>\n'
   local xkeywords = {}
   local scanner
   if lang == 'java' then
      lang = 'cpp'
      xkeywords = jkeywords
   elseif lang == 'go' then
      lang = 'cpp'
      xkeywords = gkeywords
   end

   local tok = lexer[lang](code,{},{})
   local t,val = tok()
   if not t then return nil,"empty file" end
   while t do
      val = escape(val)
      if xkeywords[val] then
         t = 'keyword'
      end
      if spans[t] then
         res:append(span(t,val))
      else
         res:append(val)
      end
      t,val = tok()
   end
   res:append '</pre>\n'
   return res:join ()
end

local function indent_line (line)
   line = line:gsub('\t','    ') -- support for barbarians ;)
   local indent = #line:match '^%s*'
   return indent,line
end

function prettify_code_blocks (txt,lang)
   local res, append = {}, table.insert
   local getline = stringx.lines(txt)
   local line = getline()
   local indent,code,start_indent
   while line do
      indent,line = indent_line(line)
      if indent >= 4 then -- indented code block
         code = {}
         while indent >= 4 do
            if not start_indent then start_indent = indent end
            append(code,line:sub(start_indent))
            line = getline()
            if line == nil then break end
            indent,line = indent_line(line)
         end
         code = concat(code,'\n')
         local llang = code:match('^%s*@lang (%a+)')
         if llang then
            lang = llang
            code = code:gsub('%s*@lang%s+%a+\n','')
         end
         code = prettify(code,lang)
         append(res,code)
         start_indent = nil
      end
      append(res,line)
      line = getline()
   end
   return concat(res,'\n')
end

local function remove_spurious_lines (txt)
   return txt:gsub('</p>%s*','</p>\n'):gsub('</pre>%s*','</pre>\n')
end

if #arg == 0 then
   return print("markdown-file-without-extension language (preview)")
end

name = arg[1]
lang = arg[2] or 'lua'
preview = arg[3]

preamble = [[
<html>
<head>
<style type="text/css">
    .keyword {font-weight: bold; color: #6666AA; }
    .number  { color: #AA6666; }
    .string  { color: #8888AA; }
    .comment { color: #666600; }
    pre { font-weight: bold; }
</style>
</head>
<body>
]]

coda = [[
</body></html>
]]

text = utils.readfile(name..'.md')
text = prettify_code_blocks(text,lang)
text = markdown(text)
text = remove_spurious_lines(text)
if preview then
   text = preamble .. text .. coda
end
utils.writefile(name..'.html',text)
	-- translate Markdown with code blocks into HTML
	-- with syntax highlighting.
	-- If article.md was the source, Lua was the language and we
	-- wanted a preview:
	-- lua prettify.lua article lua preview
	-- Without the last argument it will just write out the HTML body.
	-- Languages supported are 'lua', 'cpp', 'java' and 'go
	-- Indented code blocks may begin with an explicit @lang name line;
	-- if you do this then mark every code block explicitly
	-- e.g
	-- @lang lua
	-- print "hello world"
	--
	-- (any line)
	--
	-- @lang go
	-- fnt.Println("hello world"
	--
	-- Needs markdown.lua and Penlight.
	-- Steve Donovan, 2011 MIT license.
	require 'pl'
	require 'markdown'

	local tnext = lexer.skipws
	local concat = table.concat

	local escaped_chars = {
	['&'] = '&',
	['<'] = '<',
	['>'] = '>',
	}
	local escape_pat = '[&<>]'

	local function escape(str)
	return (str:gsub(escape_pat,escaped_chars))
	end

	local function span(t,val)
	return ('<span class="%s">%s</span>'):format(t,val)
	end

	local spans = {keyword=true,number=true,string=true,comment=true}


	local jkeywords = {
	final = true, extends = true, implements = true,
	interface = true, import = true, throws = true, null = true
	}

	local gkeywords = { byte=true,chan=true,complex64=true,
	complex128=true,defer=true,func=true,fallthrough=true,
	float32=true,float64=true,string=true,uint=true,uintptr=true,
	uint8=true,uint16=true,uint32=true,uint64=true,
	var=true,len=true,map=true,package=true,range=true,select=true,
	type=true,interface=true,int8=true,int16=true,int32=true,
	int64=true,['nil']=true,func=true
	}

	local function prettify (code,lang)
	local res = List()
	res:append '<pre>\n'
	local xkeywords = {}
	local scanner
	if lang == 'java' then
	lang = 'cpp'
	xkeywords = jkeywords
	elseif lang == 'go' then
	lang = 'cpp'
	xkeywords = gkeywords
	end

	local tok = lexer[lang](code,{},{})
	local t,val = tok()
	if not t then return nil,"empty file" end
	while t do
	val = escape(val)
	if xkeywords[val] then
	t = 'keyword'
	end
	if spans[t] then
	res:append(span(t,val))
	else
	res:append(val)
	end
	t,val = tok()
	end
	res:append '</pre>\n'
	return res:join ()
	end

	local function indent_line (line)
	line = line:gsub('\t',' ') -- support for barbarians ;)
	local indent = #line:match '^%s*'
	return indent,line
	end

	function prettify_code_blocks (txt,lang)
	local res, append = {}, table.insert
	local getline = stringx.lines(txt)
	local line = getline()
	local indent,code,start_indent
	while line do
	indent,line = indent_line(line)
	if indent >= 4 then -- indented code block
	code = {}
	while indent >= 4 do
	if not start_indent then start_indent = indent end
	append(code,line:sub(start_indent))
	line = getline()
	if line == nil then break end
	indent,line = indent_line(line)
	end
	code = concat(code,'\n')
	local llang = code:match('^%s*@lang (%a+)')
	if llang then
	lang = llang
	code = code:gsub('%s*@lang%s+%a+\n','')
	end
	code = prettify(code,lang)
	append(res,code)
	start_indent = nil
	end
	append(res,line)
	line = getline()
	end
	return concat(res,'\n')
	end

	local function remove_spurious_lines (txt)
	return txt:gsub('</p>%s','</p>\n'):gsub('</pre>%s','</pre>\n')
	end

	if #arg == 0 then
	return print("markdown-file-without-extension language (preview)")
	end

	name = arg[1]
	lang = arg[2] or 'lua'
	preview = arg[3]

	preamble = [[
	<html>
	<head>
	<style type="text/css">
	.keyword {font-weight: bold; color: #6666AA; }
	.number { color: #AA6666; }
	.string { color: #8888AA; }
	.comment { color: #666600; }
	pre { font-weight: bold; }
	</style>
	</head>
	<body>
	]]

	coda = [[
	</body></html>
	]]

	text = utils.readfile(name..'.md')
	text = prettify_code_blocks(text,lang)
	text = markdown(text)
	text = remove_spurious_lines(text)
	if preview then
	text = preamble .. text .. coda
	end
	utils.writefile(name..'.html',text)