Text.Hako

A simplist template language using a quasi-quoting approach. Hako quasi-quote expressions return a Html, which can be converted back to a String using fromHtml. Basic syntax rules: * Text is kept as-is, without any encoding performed.

>>> [hako|<p>foobar</p>|]
Html "<p>foobar</p>"

• Curly braces designate Haskell expressions, which must return an instance of typeclass ToHtml; the toHtml method is called automatically.

>>> [hako|This is {"<a>quoted</a>"}|]
Html "This is &lt;a&gt;quoted&lt;/a&gt;"

• If the opening curly brace is immediately followed by the keyword def, then the expression is interpreted as a definition instead; it works pretty much exactly like a function or constant definition in plain old Haskell, and the definition thus created can be called as a function from anywhere within the template.

>>> [hako|{def a x =<a>{x}</a>}Here's a {a "link"}.|]
Html "Here's a <a>link</a>."

• A def block can be used before it is defined.

>>> [hako|Here's a {a "link"}.{def a x =<a>{x}</a>]|]
Html "Here's a <a>link</a>."

• As is to be expected from a quasi-quoter, the current scope is carried into the template.

>>> let txt = "Hello, world!" in [hako|<div>{txt}</div>|]
Html "<div>Hello, world!</div>"

• Since {} expressions can contain any valid Haskell expression (as long as its type implements ToHtml), you can use any Haskell function that is currently in scope.

>>> [hako|{def li x=<li>x</li>}<ul>{map li [1,2,3]}</ul>|]
Html "<ul><li>1</li><li>2</li><li>3</li></ul>"

Documentation

hako :: QuasiQuoter

hakof :: QuasiQuoter

data Html

A piece of HTML source. Use fromHtml to get the HTML source back out.

Constructors

Html String

Instances

Eq Html

Show Html

ToHtml Html

Html itself is also a member of ToHtml; converting from Html to Html is an identity.