GitHub - benglard/htmlua: Lua HTML templater

One of my favorite features in the Lua language is a piece of syntactic sugar: Lua lets you remove parentheses when calling functions with a single table or string argument, e.g.

require 'torch'
print{1, 2, 3}

I have used this elegant feature to build libraries such as luaclass and luaimport.

htmlua takes advantage of this syntactic sugar to build a pure-lua HMTL templating engine. This project is now integrated into waffle.

Example Usage

local html = require 'htmlua'
return html.html {
   html.head {
      html.title "Title"
   },
   html.body {
      html.p "yo",
      html.img {
         src="https://www.google.com/images/srpr/logo11w.png"
      }
   }
}

renders as

<html><head><title>Title</title></head><body><p>yo</p><img src="https://www.google.com/images/srpr/logo11w.png"></body></html>

Amazingly, there is no compiler, no 3rd-party language, that's pure lua! That means that all of your typical lua language structure, libraries, variables, etc. can be used seamlessly. But I've built some helpers in too:

Conditionals

local x = 5
IF {
   x == 5,
   THEN(h.p "x == 5"),
   ELSE(h.p "x ~= 5")
}

Loops

Option 1

DO(function()
   local rv = ''
   for _, name in pairs(names) do
      rv = rv .. h.li(name)
   end
   return h.ul(rv)
end)

Option 2

local names = {'lua', 'python', 'javascript'}
h.ul(each(names, h.li))

Both render as:

<ul><li>lua</li><li>python</li><li>javascript</li></ul>

Option 3

h.ul(
   loop{1, 2, 3, 'test', key=5}(function(k, v)
      return h.li(v)
   end)
)

<ul><li>1</li><li>2</li><li>3</li><li>test</li><li>5</li></ul>

Comments

comment "test comment",
comment {
   h.p "p",
   h.div {
      h.h3 "h3"
   }
}

<!--test comment--><!--<p>p</p><div><h3>h3</h3></div>-->

Note that traditional lua comments can also be put inside an htmlua template, since it's executing pure-lua.

Blocks

Blocks allow for template inheritance

-- base.html
return h.html {
   h.head {
      h.title 'Base'
   },
   h.body {
      defblock 'content',
      defblock 'content2',
      h.p 'base'
   }
}

-- ext.lua
h = require 'htmlua'
base = extends 'examples/base.lua'
base = block(base, 'content')(h.h1 'content')
base = block(base, 'content2'){
   h.div {
      h.p 'content2'
   }
}

<html><head><title>Base</title></head><body><h1>content</h1><div><p>content2</p></div><p>base</p></body></html>

HTML Entities

HTML entities display reserved characters in HTML, e.g. the non-breaking space, less than, greather than, etc.

h.div {
   h.span "hello", h.lt, h.nbsp, h.gt, h.span "hello2"
}

<div><span>hello</span>&lt;&nbsp;&gt;<span>hello2</span></div>

String Interpolation

h.p '${name} is cool' % {name='htmlua'}

Async Rendering (with a larger example)

-- basetemp.lua
return h.html {
   h.head {
      h.title 'Base'
   },
   h.body {
      defblock 'content',
      h.p '${msg}'
   }
}

-- midtemp.lua
local base = extends 'examples/basetemp.lua'
return block(base, 'content'){
   h.ul(each([[${users}]], h.li)),
   defblock 'content2'
}

-- temp.lua
local base = extends 'examples/midtemp.lua'
return block(base, 'content2'){
   h.div {
      h.p {
         h.b 'Time: ',
         h.i '${time}'
      }
   }
}

local args = {
   msg = 'Hello World',
   users = {'lua', 'python', 'javascript'},
   time = os.time()
}

render('examples/temp.lua', args, print)

<html><head><title>Base</title></head><body><ul><li>lua</li><li>python</li><li>javascript</li></ul><div><p><b>Time: </b><i>1437167130</i></p></div><p>Hello World</p></body></html>

htmlua (executable)

The htmlua executable lets you compile and save lua source as html.

> htmlua -f examples/test.lua -o out.html

Inspirations

This project takes inspiration from: