Latex type families (#734)

* Support for type families in LaTeX

The code is ported over from the XHTML backend.

* Refactor XHTML and LaTeX family handling

This is mostly a consolidation effort: stripping extra exports,
inlining some short definitions, and trying to make the backends
match.

The LaTeX backend now has preliminary support for data families,
although the only the data instance head is printed (not the actual constructors).

Both backends also now use "newtype" for newtype data family
instances.

* Add some tests

4 files changed, 133 insertions, 0 deletions

diff --git a/latex-test/ref/TypeFamilies3/TypeFamilies3.tex b/latex-test/ref/TypeFamilies3/TypeFamilies3.tex
new file mode 100644
index 00000000..2a8ad297
--- /dev/null
+++ b/latex-test/ref/TypeFamilies3/TypeFamilies3.tex
@@ -0,0 +1,44 @@
+\haddockmoduleheading{TypeFamilies3}
+\label{module:TypeFamilies3}
+\haddockbeginheader
+{\haddockverb\begin{verbatim}
+module TypeFamilies3 (
+    Foo,  Bar,  Baz(Baz3, Baz2, Baz1)
+  ) where\end{verbatim}}
+\haddockendheader
+
+\begin{haddockdesc}
+\item[\begin{tabular}{@{}l}
+type\ family\ Foo\ a\ where
+\end{tabular}]\haddockbegindoc
+\haddockbeginargs
+\haddockdecltt{Foo () = Int} \\
+\haddockdecltt{Foo \_ = ()} \\
+\end{tabulary}\par
+A closed type family\par
+
+\end{haddockdesc}
+\begin{haddockdesc}
+\item[\begin{tabular}{@{}l}
+type\ family\ Bar\ a
+\end{tabular}]\haddockbegindoc
+An open family\par
+
+\end{haddockdesc}
+\begin{haddockdesc}
+\item[\begin{tabular}{@{}l}
+type\ instance\ Bar\ Int\ =\ ()\\type\ instance\ Bar\ ()\ =\ Int
+\end{tabular}]
+\end{haddockdesc}
+\begin{haddockdesc}
+\item[\begin{tabular}{@{}l}
+data\ family\ Baz\ a
+\end{tabular}]\haddockbegindoc
+A data family\par
+
+\end{haddockdesc}
+\begin{haddockdesc}
+\item[\begin{tabular}{@{}l}
+newtype\ instance\ Baz\ Double\\data\ instance\ Baz\ Int\\data\ instance\ Baz\ ()
+\end{tabular}]
+\end{haddockdesc}
\ No newline at end of file
diff --git a/latex-test/ref/TypeFamilies3/haddock.sty b/latex-test/ref/TypeFamilies3/haddock.sty
new file mode 100644
index 00000000..6e031a98
--- /dev/null
+++ b/latex-test/ref/TypeFamilies3/haddock.sty
@@ -0,0 +1,57 @@
+% Default Haddock style definitions.  To use your own style, invoke
+% Haddock with the option --latex-style=mystyle.
+
+\usepackage{tabulary} % see below
+
+% make hyperlinks in the PDF, and add an expandabale index
+\usepackage[pdftex,bookmarks=true]{hyperref}
+
+\newenvironment{haddocktitle}
+  {\begin{center}\bgroup\large\bfseries}
+  {\egroup\end{center}}
+\newenvironment{haddockprologue}{\vspace{1in}}{}
+
+\newcommand{\haddockmoduleheading}[1]{\chapter{\texttt{#1}}}
+
+\newcommand{\haddockbeginheader}{\hrulefill}
+\newcommand{\haddockendheader}{\noindent\hrulefill}
+
+% a little gap before the ``Methods'' header
+\newcommand{\haddockpremethods}{\vspace{2ex}}
+
+% inserted before \\begin{verbatim}
+\newcommand{\haddockverb}{\small}
+
+% an identifier: add an index entry
+\newcommand{\haddockid}[1]{\haddocktt{#1}\index{#1@\texttt{#1}}}
+
+% The tabulary environment lets us have a column that takes up ``the
+% rest of the space''.  Unfortunately it doesn't allow
+% the \end{tabulary} to be in the expansion of a macro, it must appear
+% literally in the document text, so Haddock inserts
+% the \end{tabulary} itself.
+\newcommand{\haddockbeginconstrs}{\begin{tabulary}{\linewidth}{@{}llJ@{}}}
+\newcommand{\haddockbeginargs}{\begin{tabulary}{\linewidth}{@{}llJ@{}}}
+
+\newcommand{\haddocktt}[1]{{\small \texttt{#1}}}
+\newcommand{\haddockdecltt}[1]{{\small\bfseries \texttt{#1}}}
+
+\makeatletter
+\newenvironment{haddockdesc}
+               {\list{}{\labelwidth\z@ \itemindent-\leftmargin
+                        \let\makelabel\haddocklabel}}
+               {\endlist}
+\newcommand*\haddocklabel[1]{\hspace\labelsep\haddockdecltt{#1}}
+\makeatother
+
+% after a declaration, start a new line for the documentation.
+% Otherwise, the documentation starts right after the declaration,
+% because we're using the list environment and the declaration is the
+% ``label''.  I tried making this newline part of the label, but
+% couldn't get that to work reliably (the space seemed to stretch
+% sometimes).
+\newcommand{\haddockbegindoc}{\hfill\\[1ex]}
+
+% spacing between paragraphs and no \parindent looks better
+\parskip=10pt plus2pt minus2pt
+\setlength{\parindent}{0cm}
diff --git a/latex-test/ref/TypeFamilies3/main.tex b/latex-test/ref/TypeFamilies3/main.tex
new file mode 100644
index 00000000..2c98043c
--- /dev/null
+++ b/latex-test/ref/TypeFamilies3/main.tex
@@ -0,0 +1,11 @@
+\documentclass{book}
+\usepackage{haddock}
+\begin{document}
+\begin{titlepage}
+\begin{haddocktitle}
+
+\end{haddocktitle}
+\end{titlepage}
+\tableofcontents
+\input{TypeFamilies3}
+\end{document}
\ No newline at end of file
diff --git a/latex-test/src/TypeFamilies3/TypeFamilies3.hs b/latex-test/src/TypeFamilies3/TypeFamilies3.hs
new file mode 100644
index 00000000..bde05fb8
--- /dev/null
+++ b/latex-test/src/TypeFamilies3/TypeFamilies3.hs
@@ -0,0 +1,21 @@
+{-# LANGUAGE TypeFamilies #-}
+
+module TypeFamilies3 where
+
+-- | A closed type family
+type family Foo a where
+  Foo () = Int
+  Foo _ = ()
+
+-- | An open family
+type family Bar a
+
+type instance Bar Int = ()
+type instance Bar () = Int
+
+-- | A data family
+data family Baz a
+
+data instance Baz () = Baz1
+data instance Baz Int = Baz2 Bool
+newtype instance Baz Double = Baz3 Float