# blazeT [![Build Status](https://travis-ci.org/johannesgerer/blazeT.svg?branch=master)](https://travis-ci.org/johannesgerer/blazeT)

A true monad (transformer) version of the
[blaze-markup](https://hackage.haskell.org/package/blaze-markup) and
[blaze-html](https://hackage.haskell.org/package/blaze-html)
libraries.

# Why?

While blaze's `Markup` and `Html` types have `Monad` instances and are
able to use the concise `do` notation.

# How?

## Backwards compatible

The library is intended to serve as a drop-in replacement for the
blaze-markup and blaze-html libraries and should be backwards
compatible:

Simply replace your `module Text.Blaze.*` imports with `module
Text.BlazeT.*` and it should give the same results.

For usage of blaze check out
their [documentation](https://jaspervdj.be/blaze/).

## Unleash the monads



# Implementation Details (from [Text.BlazeT.Internals](https://hackage.haskell.org/package/blazeT/docs/Text-BlazeT-Internals.html))

Everything build around the simple `newtype` definition of the
`MarkupT` transformer, which is basically a `WriterT` transformer
writing `Blaze.Markup`:

```Haskell
newtype MarkupT m a= MarkupT { fromMarkupT :: WriterT B.Markup m a }
```

Wrappers used to lift all `Blaze` entities into `BlazeT` are trivially
expressible using basic `WriterT` class methods:

```Haskell
-- | Wrapping `Blaze.Markup` is simply `WriterT.tell`
wrapMarkupT :: Monad m => B.Markup -> MarkupT m ()
wrapMarkupT = tell

-- | Wrapping functions that modify `Blaze.Markup` is simply  `WriterT.censor`
wrapMarkupT2 ::  Monad m => (B.Markup -> B.Markup)
                 -> MarkupT m a -> MarkupT m a
wrapMarkupT2 = censor

```