diff --git a/doc/appendix.tex b/doc/appendix.tex
new file mode 100644
index 0000000..9d92d53
--- /dev/null
+++ b/doc/appendix.tex
@@ -0,0 +1,178 @@
+\part{Appendix}
+
+\addchap{Syntax}
+
+\begin{grammar}
+<letter> = `A' | `B' | … | `Z' | `a' | `b' | … | `z' | `\_'.
+
+<counting-digit> = `1' | `2' | `3' | `4' | `5' | `6' | `7' | `8' | `9'.
+
+<decimal-digit> = `0' | <counting-digit>.
+
+<hex-digit> = <decimal-digit> | `A' | `B' | … | `F' | `a' | `b' | … | `f'.
+
+<binary-digit> = `0' | `1'.
+
+<hex-character> = `\\x' <hex-digit> <hex-digit>.
+
+<escaped-character> = `\\' \\
+	(`n' | `a' | `b' | `t' | `f' | `r' | `v' | `\\' | `\textquotesingle' | `\textquotedbl' | `?\@' | `0').
+
+<printable-character> = \enspace? a printable ASCII character\space?.
+
+<character> = <printable-character> | <escaped-character> | <hex-digit>.
+
+<identifier> = <letter> \{<letter> | <decimal-digit>\}.
+
+<identifier-definition> = <identifier> [`*'].
+
+<trait-identifier> = `#' <identifier>.
+
+<integer-literal> = `0' | <counting-digit> \{<decimal-digit>\}.
+
+<word-literal> = <integer-literal> `u'
+	\alt{} `0' (`X' | `x') <hex-digit> \{<hex-digit>\}
+	\alt{} `0' (`B' | `b') <binary-digit> \{<binary-digit>\}.
+
+<real-literal> = <integer-literal> `.\@' <decimal-digit> \{<decimal-digit>\}
+	\alt{} <integer-literal>\} `e' [`+' | `-'] <decimal-digit> \{<decimal-digit>\}.
+
+<string-literal> = `\textquotedbl' \{<character>\} `\textquotedbl'.
+
+<character-literal> = `\textquotesingle' <character> `\textquotesingle'.
+
+<literal> = <integer-literal> | <word-literal> | <real-literal>
+	\alt{} <string-literal> | <character-literal>
+	\alt{} `true' | `false' | `nil'.
+
+<trait> = <trait-identifier> `(' [<types>] `)'.
+
+<cast> = `cast' `(' <expression> `:\@' <type> `)'.
+
+<procedure-call> = <designator> `(' [<expressions>] `)'.
+
+<relation-operator> = `=' | `<>' | `<' | `>' | `<=' | `>='.
+
+<multiplication-operator> = `*' | `/' | `\%'.
+
+<addition-operator> = `+' | `-'.
+
+<shift-operator> = `<<' | `>>'.
+
+<unary-operator> = `@' | `~' | `-'.
+
+<selector> = `[' <expression> `]' | `.\@' <identifier> | `^'.
+
+<case> = <expressions> `:\@' <optional-statements>.
+
+<designator> = <reference> <selector> | <identifier>.
+
+<reference> = <literal>
+	\alt{} <designator>
+	\alt{} <trait>
+	\alt{} <cast>
+	\alt{} <procedure-call>
+	\alt{} `(' <expression> `)'.
+
+<factor> = <unary-operator> <factor> | <reference>.
+
+<term> = <factor> \{<multiplication-operator> <factor>\}.
+
+<simple-expression> = <term> \{<addition-operator> <term>\}.
+
+<comparand> = <simple-expression> \{<shift-operator> <simple-expression>\}.
+
+<relation> = <comparand> \{<relation-operator> <comparand>\}.
+
+<operand> = <relation> \{`&' <relation>\}.
+
+<expression> = <operand> \{(`or' | `xor') <operand>\}.
+
+<expressions> = <expression> \{`,' <expression>\}.
+
+<identifier-definitions> = <identifier-definition> \{`,' <identifier-definition>\}.
+
+<types> = <type> \{`,' <type>\}.
+
+<required-statements> = <statement> \{`;' <statement>\}.
+
+<optional-statements> = [<required-statements>].
+
+<return-declaration> = [`->' `!\@' | `->' type].
+
+<field> = <identifier> `:\@' <type>.
+
+<array-type> = `[' <expression> `]' <type>.
+
+<pointer-type> = `^' <type>.
+
+<record-type> = `record' [`(' <identifier> `)'] [<field> \{`;' <field>\}] `end'.
+
+<enumeration-type> = `(' <identifier> \{`,' <identifier>\} `)'.
+
+<procedure-type> = `proc' `(' [<types>] `)' <return-declaration>.
+
+<type> = <array-type>
+	\alt{} <pointer-type>
+	\alt{} <record-type>
+	\alt{} <enumeration-type>
+	\alt{} <procedure-type>
+	\alt{} <identifier>.
+
+<assignment> = <designator> `:=' <expression>.
+
+<if-statement> = `if' <expression> `then' <optional-statements> \\
+    \{`elsif' <expression> `then' <optional-statements>\} \\
+	{[`else' <optional-statements>]} `end'.
+
+<while-statement> = `while' <expression> `do' <optional-statements> \\
+    \{`elsif' <expression> `do' <optional-statements>\} `end'.
+
+<defer-statement> = `defer' <optional-statements> `end'.
+
+<case-statement> = `case' <expression> `of' <case> \{`|' case\} \\
+	{[`else' <optional-statements>]} `end'.
+
+<label-declaration> = `.\@' <identifier>.
+
+<goto-statement> = `goto' <identifier>.
+
+<statement> = <assignment> | <procedure-call> | <defer-statement>
+    | <label-declaration> | <goto-statement> |
+    | <while-statement> | <if-statement> | <case-statement>.
+
+<statement-part> = [`begin' <required-statements>
+	\alt{} `return' <expression>
+	\alt{} `begin' <required-statements> `;' `return' <expression>].
+
+<constant-declaration> = <identifier-definition> `:=' <expression>.
+
+<constant-part> = [`const' \{<constant-declaration> `;'\}].
+
+<variable-declaration> = <identifier-definitions> `:\@' <type> \\
+	{[`:=' (<expression> | `extern')]}.
+
+<variable-part> = [`var' \{<variable-declaration> `;'\}].
+
+<type-declaration> = <identifier-definition> `=' <type>.
+
+<type-part> = [`type' \{<type-declaration> `;'\}].
+
+<import-declaration> = <identifier> \{`.\@' <identifier>\}.
+
+<import-part> = [`import' \{import-declaration `;'\}].
+
+<procedure-heading> = `proc' <identifier-definition> \\
+	`(' [<field> \{`,' <field>\}] `)' <return-declaration>.
+
+<block> = <constant-part> <variable-part> <statement-part> `end'.
+
+<procedure-declaration> = <procedure-heading> `;' (block | `extern').
+
+<declaration-sequence> = <import-part> \\
+    <constant-part> <type-part> <variable-part> \\
+	\{<procedure-declaration> `;'\}.
+
+<program> = `program' `;' <declaration-sequence> <statement-part> `end' `.\@'
+	\alt{} `module' `;' <declaration-sequence> `end' `.\@'.
+\end{grammar}
diff --git a/doc/credits.bib b/doc/credits.bib
new file mode 100644
index 0000000..0af1709
--- /dev/null
+++ b/doc/credits.bib
@@ -0,0 +1,5 @@
+@book{oberon,
+	author = "Niklaus Wirth",
+	title = "The Programming Language Oberon",
+	year = 2016
+}
diff --git a/doc/language.tex b/doc/language.tex
index bfa21cb..a18dac8 100644
--- a/doc/language.tex
+++ b/doc/language.tex
@@ -1,28 +1,24 @@
-\documentclass{scrreprt}
-
-\usepackage[T1]{fontenc}
-\usepackage{tabularx}
-\usepackage{booktabs}
-\usepackage{listings}
-\usepackage{syntax}
-
-\title{The programming language Elna}
-
-\begin{document}
-
-\maketitle
-\tableofcontents
-
-\chapter{Introduction}
-
-Elna is a simple, imperative, low-level programming language.
-
-It is intendet to accompany other languages in the areas, where a high-level
-language doesn't fit well. It is also supposed to be an intermediate
-representation for a such high-level hypothetical programming language.
-
 \part{Language}
 
+An Elna program consists of one or more source files, called \textbf{modules}.
+
+Each module can declare \textbf{types}, \textbf{global variables} and
+\textbf{procedures}, used by this module or exported to be used by other
+modules.
+
+Each procedure can get some input and produce an output as a result of
+executing a \textbf{statement block}, a list, where each \textbf{statement}
+is executed in the order it appears in the block.
+
+Statement components are other statement blocks and \textbf{expressions},
+where a statement has control over the evaluation of its components.
+Statements can also modify the state of the procedure or the program by
+mutating variables.
+
+Most simple expressions are identifiers referencing program's symbols and
+literals. These atomic expressions can be combined to more complex expressions
+by applying various operations to one or more expressions.
+
 \chapter{Expressions}
 
 The expression \verb|@r.field| includes 3 expressions:
@@ -76,343 +72,3 @@ bitwise not.
 
 \chapter{Conditional statements}
 \chapter{Loop statements}
-
-\part{Type system}
-
-\begin{grammar}
-<type> = <array-type>
-	\alt{} <pointer-type>
-	\alt{} <record-type>
-	\alt{} <enumeration-type>
-	\alt{} <procedure-type>
-	\alt{} <identifier>.
-\end{grammar}
-
-\chapter{Primitive types}
-
-\begin{itemize}
-	\item Pointer
-	\item Word
-	\item Int
-	\item Bool
-	\item String
-	\item Char
-\end{itemize}
-
-\chapter{Pointer types}
-
-\begin{grammar}
-<pointer-type> = `^' <type>.
-\end{grammar}
-
-\begin{lstlisting}[caption=Example]
-program;
-var
-  x: Int;
-  y: ^Int;
-begin
-  y := @x;
-  y^ := 0
-end.
-\end{lstlisting}
-
-\chapter{Static array}
-
-\begin{grammar}
-<array-type> = `[' <expression> `]' <type>.
-\end{grammar}
-
-\begin{lstlisting}[caption=Example]
-program;
-var
-  array: [3]Int := [1, 2, 3];
-begin
-  array[1] := array[2]
-end.
-\end{lstlisting}
-
-\chapter{Procedure types}
-
-\begin{grammar}
-<procedure-heading> = `proc' <identifier-definition> \\
-	`(' [<field> \{`,' <field>\}] `)' <return-declaration>.
-
-<block> = <constant-part> <variable-part> <statement-part> `end'.
-
-<procedure-declaration> = <procedure-heading> `;' (block | `extern').
-
-<return-declaration> = [`->' `!\@' | `->' type].
-
-<procedure-type> = `proc' `(' [<types>] `)' <return-declaration>.
-\end{grammar}
-
-\begin{lstlisting}[caption=Example]
-program;
-var
-  a: proc(Int) -> Int;
-
-proc f(x: Int) -> Int;
-end;
-
-begin
-  a := f;
-  a(0)
-end.
-\end{lstlisting}
-
-\chapter{Records}
-
-\begin{grammar}
-<field> = <identifier> `:\@' <type>.
-
-<record-type> = `record' [`(' <identifier> `)'] [<field> \{`;' <field>\}] `end'.
-\end{grammar}
-
-\begin{lstlisting}[caption=Example]
-program;
-type
-  T = record
-    x: Int
-  end;
-  U = record(T)
-    y: Int;
-    z: Int
-  end;
-
-var
-  u: U;
-begin
-  u := U(0, 1, 2);
-  u.x := 3
-end.
-\end{lstlisting}
-
-\chapter{Enumerations}
-
-\begin{grammar}
-<enumeration-type> = `(' <identifier> \{`,' <identifier>\} `)'.
-\end{grammar}
-
-\begin{lstlisting}[caption=Example]
-program;
-type
-  E = (one, two, three);
-var
-  e: E;
-begin
-  e := E.one
-end.
-\end{lstlisting}
-
-\chapter{Type operations}
-
-\chapter{Cast}
-
-\begin{grammar}
-<cast> = `cast' `(' <expression> `:\@' <type> `)'.
-\end{grammar}
-
-The type of an object can be reinterpreted with a cast expression: \\
-\verb|cast(object: Type)|.
-
-\chapter{Traits}
-
-\begin{grammar}
-<trait-identifier> = `#' <identifier>.
-
-<trait> = <trait-identifier> `(' [<types>] `)'.
-\end{grammar}
-
-Traits allow to query some information about the types, like their size or
-field offset or alignment. Calling a trait looks like a procedure call but
-traits names start with a \verb|#| and their arguments are type expressions and
-not value expressions.
-
-Supported compiler traits:
-
-\begin{itemize}
-	\item \verb|#size(T)| queries type size.
-	\item \verb|#align(T)| queries type alignment.
-	\item \verb|#offset(T, F)| queries the offset of the field \verb|F| in the record \verb|T|.
-\end{itemize}
-
-\part{Appendix}
-
-\chapter{Syntax}
-
-\begin{grammar}
-<letter> = `A' | `B' | … | `Z' | `a' | `b' | … | `z' | `\_'.
-
-<counting-digit> = `1' | `2' | `3' | `4' | `5' | `6' | `7' | `8' | `9'.
-
-<decimal-digit> = `0' | <counting-digit>.
-
-<hex-digit> = <decimal-digit> | `A' | `B' | … | `F' | `a' | `b' | … | `f'.
-
-<binary-digit> = `0' | `1'.
-
-<hex-character> = `\\x' <hex-digit> <hex-digit>.
-
-<escaped-character> = `\\' \\
-	(`n' | `a' | `b' | `t' | `f' | `r' | `v' | `\\' | `\textquotesingle' | `\textquotedbl' | `?\@' | `0').
-
-<printable-character> = \enspace? a printable ASCII character\space?.
-
-<character> = <printable-character> | <escaped-character> | <hex-digit>.
-
-<identifier> = <letter> \{<letter> | <decimal-digit>\}.
-
-<identifier-definition> = <identifier> [`*'].
-
-<trait-identifier> = `#' <identifier>.
-
-<integer-literal> = `0' | <counting-digit> \{<decimal-digit>\}.
-
-<word-literal> = <integer-literal> `u'
-	\alt{} `0' (`X' | `x') <hex-digit> \{<hex-digit>\}
-	\alt{} `0' (`B' | `b') <binary-digit> \{<binary-digit>\}.
-
-<real-literal> = <integer-literal> `.\@' <decimal-digit> \{<decimal-digit>\}
-	\alt{} <integer-literal>\} `e' [`+' | `-'] <decimal-digit> \{<decimal-digit>\}.
-
-<string-literal> = `\textquotedbl' \{<character>\} `\textquotedbl'.
-
-<character-literal> = `\textquotesingle' <character> `\textquotesingle'.
-
-<literal> = <integer-literal> | <word-literal> | <real-literal>
-	\alt{} <string-literal> | <character-literal>
-	\alt{} `true' | `false' | `nil'.
-
-<trait> = <trait-identifier> `(' [<types>] `)'.
-
-<cast> = `cast' `(' <expression> `:\@' <type> `)'.
-
-<procedure-call> = <designator> `(' [<expressions>] `)'.
-
-<relation-operator> = `=' | `<>' | `<' | `>' | `<=' | `>='.
-
-<multiplication-operator> = `*' | `/' | `\%'.
-
-<addition-operator> = `+' | `-'.
-
-<shift-operator> = `<<' | `>>'.
-
-<unary-operator> = `@' | `~' | `-'.
-
-<selector> = `[' <expression> `]' | `.\@' <identifier> | `^'.
-
-<case> = <expressions> `:\@' <optional-statements>.
-
-<designator> = <reference> <selector> | <identifier>.
-
-<reference> = <literal>
-	\alt{} <designator>
-	\alt{} <trait>
-	\alt{} <cast>
-	\alt{} <procedure-call>
-	\alt{} `(' <expression> `)'.
-
-<factor> = <unary-operator> <factor> | <reference>.
-
-<term> = <factor> \{<multiplication-operator> <factor>\}.
-
-<simple-expression> = <term> \{<addition-operator> <term>\}.
-
-<comparand> = <simple-expression> \{<shift-operator> <simple-expression>\}.
-
-<relation> = <comparand> \{<relation-operator> <comparand>\}.
-
-<operand> = <relation> \{`&' <relation>\}.
-
-<expression> = <operand> \{(`or' | `xor') <operand>\}.
-
-<expressions> = <expression> \{`,' <expression>\}.
-
-<identifier-definitions> = <identifier-definition> \{`,' <identifier-definition>\}.
-
-<types> = <type> \{`,' <type>\}.
-
-<required-statements> = <statement> \{`;' <statement>\}.
-
-<optional-statements> = [<required-statements>].
-
-<return-declaration> = [`->' `!\@' | `->' type].
-
-<field> = <identifier> `:\@' <type>.
-
-<array-type> = `[' <expression> `]' <type>.
-
-<pointer-type> = `^' <type>.
-
-<record-type> = `record' [`(' <identifier> `)'] [<field> \{`;' <field>\}] `end'.
-
-<enumeration-type> = `(' <identifier> \{`,' <identifier>\} `)'.
-
-<procedure-type> = `proc' `(' [<types>] `)' <return-declaration>.
-
-<type> = <array-type>
-	\alt{} <pointer-type>
-	\alt{} <record-type>
-	\alt{} <enumeration-type>
-	\alt{} <procedure-type>
-	\alt{} <identifier>.
-
-<assignment> = <designator> `:=' <expression>.
-
-<if-statement> = `if' <expression> `then' <optional-statements> \\
-    \{`elsif' <expression> `then' <optional-statements>\} \\
-	{[`else' <optional-statements>]} `end'.
-
-<while-statement> = `while' <expression> `do' <optional-statements> \\
-    \{`elsif' <expression> `do' <optional-statements>\} `end'.
-
-<defer-statement> = `defer' <optional-statements> `end'.
-
-<case-statement> = `case' <expression> `of' <case> \{`|' case\} \\
-	{[`else' <optional-statements>]} `end'.
-
-<label-declaration> = `.\@' <identifier>.
-
-<goto-statement> = `goto' <identifier>.
-
-<statement> = <assignment> | <procedure-call> | <defer-statement>
-    | <label-declaration> | <goto-statement> |
-    | <while-statement> | <if-statement> | <case-statement>.
-
-<statement-part> = [`begin' <required-statements>
-	\alt{} `return' <expression>
-	\alt{} `begin' <required-statements> `;' `return' <expression>].
-
-<constant-declaration> = <identifier-definition> `:=' <expression>.
-
-<constant-part> = [`const' \{<constant-declaration> `;'\}].
-
-<variable-declaration> = <identifier-definitions> `:\@' <type> \\
-	{[`:=' (<expression> | `extern')]}.
-
-<variable-part> = [`var' \{<variable-declaration> `;'\}].
-
-<type-declaration> = <identifier-definition> `=' <type>.
-
-<type-part> = [`type' \{<type-declaration> `;'\}].
-
-<import-declaration> = <identifier> \{`.\@' <identifier>\}.
-
-<import-part> = [`import' \{import-declaration `;'\}].
-
-<procedure-heading> = `proc' <identifier-definition> \\
-	`(' [<field> \{`,' <field>\}] `)' <return-declaration>.
-
-<block> = <constant-part> <variable-part> <statement-part> `end'.
-
-<procedure-declaration> = <procedure-heading> `;' (block | `extern').
-
-<declaration-sequence> = <import-part> \\
-    <constant-part> <type-part> <variable-part> \\
-	\{<procedure-declaration> `;'\}.
-
-<program> = `program' `;' <declaration-sequence> <statement-part> `end' `.\@'
-	\alt{} `module' `;' <declaration-sequence> `end' `.\@'.
-\end{grammar}
-
-\end{document}
diff --git a/doc/report.tex b/doc/report.tex
new file mode 100644
index 0000000..e3ed640
--- /dev/null
+++ b/doc/report.tex
@@ -0,0 +1,46 @@
+\documentclass{scrreprt}
+
+\usepackage[T1]{fontenc}
+\usepackage{tabularx}
+\usepackage{booktabs}
+\usepackage{listings}
+\usepackage{syntax}
+\usepackage[backend=biber,style=verbose-ibid,dashed=false]{biblatex}
+
+% Do not start chapter on a new page.
+\RedeclareSectionCommand[
+  style=section,
+  indent=0pt
+]{chapter}
+
+\bibliography{credits}
+
+\title{The programming language Elna}
+\author{Eugen Wissner}
+
+\begin{document}
+
+\maketitle
+\tableofcontents
+
+\addchap{Introduction}
+
+Elna is a simple, imperative, low-level programming language.
+
+It is intendet to accompany other languages in the areas, where a high-level
+language doesn't fit well. It is also supposed to be an intermediate
+representation for a such high-level hypothetical programming language.
+
+\addchap{Credits}
+
+Since Elna syntactically resembles Oberon larger parts of this specification
+are derived from the Oberon report\footnote{\cite[]{oberon}}.
+
+\include{language}
+\include{type-system}
+\include{appendix}
+
+% \addcontentsline{toc}{chapter}{References}
+\printbibliography[heading=bibintoc, title=References]{}
+
+\end{document}
diff --git a/doc/type-system.tex b/doc/type-system.tex
new file mode 100644
index 0000000..4ac36e4
--- /dev/null
+++ b/doc/type-system.tex
@@ -0,0 +1,158 @@
+\part{Type system}
+
+\begin{grammar}
+<type> = <array-type>
+	\alt{} <pointer-type>
+	\alt{} <record-type>
+	\alt{} <enumeration-type>
+	\alt{} <procedure-type>
+	\alt{} <identifier>.
+\end{grammar}
+
+\chapter{Primitive types}
+
+\begin{itemize}
+	\item Pointer
+	\item Word
+	\item Int
+	\item Bool
+	\item String
+	\item Char
+\end{itemize}
+
+\chapter{Pointer types}
+
+\begin{grammar}
+<pointer-type> = `^' <type>.
+\end{grammar}
+
+\begin{lstlisting}[caption=Example]
+program;
+var
+  x: Int;
+  y: ^Int;
+begin
+  y := @x;
+  y^ := 0
+end.
+\end{lstlisting}
+
+\chapter{Static array}
+
+\begin{grammar}
+<array-type> = `[' <expression> `]' <type>.
+\end{grammar}
+
+\begin{lstlisting}[caption=Example]
+program;
+var
+  array: [3]Int := [1, 2, 3];
+begin
+  array[1] := array[2]
+end.
+\end{lstlisting}
+
+\chapter{Procedure types}
+
+\begin{grammar}
+<procedure-heading> = `proc' <identifier-definition> \\
+	`(' [<field> \{`,' <field>\}] `)' <return-declaration>.
+
+<block> = <constant-part> <variable-part> <statement-part> `end'.
+
+<procedure-declaration> = <procedure-heading> `;' (block | `extern').
+
+<return-declaration> = [`->' `!\@' | `->' type].
+
+<procedure-type> = `proc' `(' [<types>] `)' <return-declaration>.
+\end{grammar}
+
+\begin{lstlisting}[caption=Example]
+program;
+var
+  a: proc(Int) -> Int;
+
+proc f(x: Int) -> Int;
+end;
+
+begin
+  a := f;
+  a(0)
+end.
+\end{lstlisting}
+
+\chapter{Records}
+
+\begin{grammar}
+<field> = <identifier> `:\@' <type>.
+
+<record-type> = `record' [`(' <identifier> `)'] [<field> \{`;' <field>\}] `end'.
+\end{grammar}
+
+\begin{lstlisting}[caption=Example]
+program;
+type
+  T = record
+    x: Int
+  end;
+  U = record(T)
+    y: Int;
+    z: Int
+  end;
+
+var
+  u: U;
+begin
+  u := U(0, 1, 2);
+  u.x := 3
+end.
+\end{lstlisting}
+
+\chapter{Enumerations}
+
+\begin{grammar}
+<enumeration-type> = `(' <identifier> \{`,' <identifier>\} `)'.
+\end{grammar}
+
+\begin{lstlisting}[caption=Example]
+program;
+type
+  E = (one, two, three);
+var
+  e: E;
+begin
+  e := E.one
+end.
+\end{lstlisting}
+
+\chapter{Type operations}
+
+\chapter{Cast}
+
+\begin{grammar}
+<cast> = `cast' `(' <expression> `:\@' <type> `)'.
+\end{grammar}
+
+The type of an object can be reinterpreted with a cast expression: \\
+\verb|cast(object: Type)|.
+
+\chapter{Traits}
+
+\begin{grammar}
+<trait-identifier> = `#' <identifier>.
+
+<trait> = <trait-identifier> `(' [<types>] `)'.
+\end{grammar}
+
+Traits allow to query some information about the types, like their size or
+field offset or alignment. Calling a trait looks like a procedure call but
+traits names start with a \verb|#| and their arguments are type expressions and
+not value expressions.
+
+Supported compiler traits:
+
+\begin{itemize}
+	\item \verb|#size(T)| queries type size.
+	\item \verb|#align(T)| queries type alignment.
+	\item \verb|#offset(T, F)| queries the offset of the field \verb|F| in the record \verb|T|.
+\end{itemize}
diff --git a/rakelib/doc.rake b/rakelib/doc.rake
index d719c80..54f5d35 100644
--- a/rakelib/doc.rake
+++ b/rakelib/doc.rake
@@ -7,17 +7,26 @@ require 'pathname'
 require 'rake/clean'
 
 CLEAN.include 'build/doc'
-
 directory 'build/doc'
 
-rule /build\/doc\/\w+.pdf/ => lambda { |t|
-  [
-    Pathname.new(t).relative_path_from('build').sub_ext('.tex').to_path,
-    'build/doc'
-  ]
-} do |t|
-  sh 'pdflatex', '--output-directory', 'build/doc', t.prerequisites.first
+rule '.bbl' => '.bcf' do |t|
+  task_target = Pathname.new t.name
+  chdir = 'doc'
+  output_directory = task_target.dirname.relative_path_from(chdir).to_path
+  source = task_target.basename('.bbl').to_path
+
+  sh 'biber', '-output-directory', output_directory, source, chdir:
+end
+
+namespace :doc do
+  task :tex do
+    sh 'pdflatex', '-output-directory', '../build/doc', 'report', chdir: 'doc'
+  end
 end
 
 desc 'Generate documentation'
-task doc: 'build/doc/language.pdf'
+task doc: 'doc:tex' do
+  Rake::Task['build/doc/report.bbl'].invoke
+  Rake::Task['doc:tex'].reenable
+  Rake::Task['doc:tex'].invoke
+end