Overview

BlazeHtml is a blazingly fast HTML combinator library for the Haskell programming language. It embeds HTML templates in Haskell code for optimal efficiency and composability.

I think Yesod uses this package for HTML generation. At any rate, I came across this package when I needed to inject HTML into a page that was getting escaped. The function preEscapedToHtml did the trick. See https://jaspervdj.be/blaze/docs/Text-Blaze-Html.html.

Installation

blaze-html comes with Stack. You can add it to your project's package.yaml.

Snippets

preEscapedToHtml

This function is used on the Haskell Roulette website to output the HTML pre-generated by the CMark package.

In particular, the getPackageR handler:

{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE TypeFamilies #-}
module Handler.Package where

import Import
import Text.Blaze.Html (preEscapedToHtml)

getPackageR :: HaskellPackageId -> Handler Html
getPackageR name = do
    package <- runDB $ get404 name

    defaultLayout $ do
        setTitle "Welcome To Package!"
        $(widgetFile "package")

And the package.hamlet template:

<div .masthead>
    <div .container>
        <div .row>
            <h1 .header>
                Package #{haskellPackageName package}!

<div .container>
    <div .bs-docs-section>
    $maybe notes <- (haskellPackageNotes package)
        #{preEscapedToHtml notes}
    $nothing
        <p>No notes yet.