Text.LaTeX.Base.Writer

The writer monad applied to LaTeX values. Useful to compose LaTeX values using the do notation:

 anExample :: Monad m => LaTeXT m ()
 anExample = do
   documentclass [] article
   author "Daniel Monad"
   title "LaTeX and do notation"
   document $ do
     maketitle
     section "Some words"
     "Using " ; texttt "do" ; " notation "
     "you avoid many ocurrences of the "
     texttt "(<>)" ; " operator and a lot of "
     "parentheses. With the cost of a monad."

Since LaTeXT is a monad transformer, you can do also:

 anotherExample :: LaTeXT IO ()
 anotherExample = lift (readFileTex "foo") >>= verbatim

This way, it is easy (without carrying arguments) to include IO outputs in the LaTeX document, like files, times or random objects.

Another approach could be to have custom counters, label management or any other user-defined feature.

Of course, you can always use the simpler interface provided by the plain LaTeX type.

Another thing you should know about the LaTeX Writer Monad. Don't try to get values from computations with no results (like raw foo).

LaTeXT writer

data LaTeXT m a

WriterT monad transformer applied to LaTeX values.

Instances

MonadTrans LaTeXT

Monad m => Monad (LaTeXT m)

Functor f => Functor (LaTeXT f)

Applicative f => Applicative (LaTeXT f)

MonadIO m => MonadIO (LaTeXT m)

Monad m => Eq (LaTeXT m a)

Warning: this instance only exists for the Num instance.

Monad m => Floating (LaTeXT m a)

Undefined methods: asinh, atanh and acosh.

Monad m => Fractional (LaTeXT m a)

Division uses the LaTeX frac command.

Monad m => Num (LaTeXT m a)

Careful! Method signum is undefined. Don't use it!

Monad m => Show (LaTeXT m a)

Warning: this instance only exists for the Num instance.

Monad m => IsString (LaTeXT m a)

Be careful when using fromString over a LaTeXT value, the returned value of the computation is bottom (i.e. undefined).

Monad m => Monoid (LaTeXT m a)

mappend = >>.

Monad m => LaTeXC (LaTeXT m a)

type LaTeXT_ m = LaTeXT m ()

Type synonym for empty LaTeXT computations.

runLaTeXT :: Monad m => LaTeXT m a -> m (Either String a, LaTeX)

Running a LaTeXT computation returns the final LaTeX value and either a String if the computation didn't contain any value or the value itself otherwise.

execLaTeXT :: Monad m => LaTeXT m a -> m LaTeX

This is the usual way to run the LaTeXT monad and obtain a LaTeX value.

 execLaTeXT = liftM snd . runLaTeXT

If anExample is defined as above (at the top of this module documentation), use the following to get the LaTeX value generated out.

 myLaTeX :: Monad m => m LaTeX
 myLaTeX = execLaTeXT anExample

execLaTeXTWarn :: Monad m => LaTeXT m a -> m (LaTeX, [Warning])

Version of execLaTeXT with possible warning messages. This function applies checkAll to the LaTeX output.

extractLaTeX :: Monad m => LaTeXT m a -> LaTeXT m (a, LaTeX)

This function run a LaTeXT computation, lifting the result again in the monad.

extractLaTeX_ :: Monad m => LaTeXT m a -> LaTeXT m LaTeX

Executes a LaTeXT computation, embedding it again in the LaTeXT monad.

 extractLaTeX_ = liftM snd . extractLaTeX

This function was heavily used in the past by HaTeX-meta to generate those .Monad modules. The current purpose is to implement the LaTeXC instance of LaTeXT, which is closely related.

textell :: Monad m => LaTeX -> LaTeXT m ()

With textell you can append LaTeX values to the state of the LaTeXT monad.

rendertexM :: (Render a, Monad m) => a -> LaTeXT m ()

Just like rendertex, but with LaTeXT output.

 rendertexM = textell . rendertex

liftFun :: Monad m => (LaTeX -> LaTeX) -> LaTeXT m a -> LaTeXT m a

Lift a function over LaTeX values to a function acting over the state of a LaTeXT computation.

liftOp :: Monad m => (LaTeX -> LaTeX -> LaTeX) -> LaTeXT m a -> LaTeXT m b -> LaTeXT m b

Lift an operator over LaTeX values to an operator acting over the state of two LaTeXT computations.

Note: The returned value is the one returned by the second argument of the lifted operator.

Errors

throwError :: Monad m => String -> LaTeXT m a

The fail method of the LaTeXT monad.

merror :: Monad m => String -> LaTeXT m a -> LaTeXT m b

Function merror casts a value contained in a monad m to the bottom value of another type. If you try to evaluate this value, you will get an error message with the String passed as argument to merror.

Re-export

lift :: MonadTrans t => forall m a. Monad m => m a -> t m a

Lift a computation from the argument monad to the constructed monad.

liftIO :: MonadIO m => forall a. IO a -> m a

Lift a computation from the IO monad.