lua-html

Simple templating in Lua 5.2+

This module provides an easy way to write html from Lua code.

local html = require'html'

local myTemplate = html.div {
    html.p "paragraph",
    html.a.href"#anchor" [[Text]],
    html.img.href'file.jpg'.class'big'
}

--Or:
local myTemplate = html(function(_ENV)
    return div {
        p "paragraph",
        a.href'#anchor' "Text",
        img.href'file.jpg'.class'big'
    }
end)

Usage

The html table contains an HtmlElement object for every valid html5 element, as well as a special element called group, which acts as an HtmlElement with no start or end tag -- it simply has content. Because table is a Lua global, the table element is known as html.tab

An HtmlElement object has the following properties:

• Calling an HtmlElement with a value or list of values will return a new HtmlElement with the values appended to its content property.

div {"hello"} --> <div>hello</div>

div {1,2,3} {4,5,6} '7' --> <div>1234567</div>

• Concat-ing an HtmlElement with something else will return an html.group of the elements (If one of the elements is already a group, it will return a new group with the other element added)

p "paragraph1" .. p "paragraph2" --> <p>paragraph1</p><p>paragraph2</p>

p{"Hello "..strong"there".."!"} --> <p>Hello <strong>there</strong>!</p> 

• Indexing an HtmlElement will return a function that accepts a value, and returns a new element with the attribute of the index set.

div.class'hello' --> <div class="hello"></div>

• Calling tostring on an HtmlElement will return the html as a string

• HtmlElements also have to following properties:

  • tag: the tag name
  • content: a list of child nodes - can be other HtmlElements or strings
  • attrs: a map of attribute names to values

  These properties should be treated as read-only

_ENV shortcut

html does not pollute the global namespace. However, sometimes it is useful to have access to all html elements unprefixed by html. You could do something like this:

;(function(_ENV)
    print'Making template!'
    return div.class'greeting' {
        'hi'
    }
end)(html)

This code would set the _ENV of the code fragment to lookup globals in the html table. A metatable is set so that unknown tags are checked in the global _ENV. This allows access to the Lua standard library -- print, string, coroutine, etc. are all still available. However, the Lua global table conflicts with the html element table. Because of this, the html element is known as tab.

Templating is much easier without prefixes, so as a shortcut, calling html with a function will call that function with html as an argument. This allows this:

html(function(_ENV)
    print'Making template!'

    return div.class'greeting' {
        'hi'
    }
end)