From 3b7fbf85d39bd176b840b64a9abd5a1ff14fa6d7 Mon Sep 17 00:00:00 2001
From: Karl Berry <karl@freefriends.org>
Date: Wed, 17 May 2017 21:51:34 +0000
Subject: ebproof (17may17)

git-svn-id: svn://tug.org/texlive/trunk@44392 c570f23f-e606-0410-a88d-b1316a301751
---
 Master/texmf-dist/doc/latex/ebproof/ebproof.tex | 337 ++++++++++++++++--------
 1 file changed, 222 insertions(+), 115 deletions(-)

(limited to 'Master/texmf-dist/doc/latex/ebproof/ebproof.tex')

diff --git a/Master/texmf-dist/doc/latex/ebproof/ebproof.tex b/Master/texmf-dist/doc/latex/ebproof/ebproof.tex
index 194a02827b0..eeb93e5cdff 100644
--- a/Master/texmf-dist/doc/latex/ebproof/ebproof.tex
+++ b/Master/texmf-dist/doc/latex/ebproof/ebproof.tex
@@ -1,5 +1,5 @@
 %% ebproof.sty
-%% Copyright 2015 Emmanuel Beffara <manu@beffara.org>
+%% Copyright 2017 Emmanuel Beffara <manu@beffara.org>
 %
 % This work may be distributed and/or modified under the
 % conditions of the LaTeX Project Public License, either version 1.3
@@ -21,7 +21,7 @@
 
 \title{The \package{ebproof} package}
 \author{Emmanuel Beffara \\ \url{manu@beffara.org}}
-\date{Version 1.1 \\ March 13, 2015}
+\date{Version 2.0 \\ March 17, 2017}
 
 \usepackage{amssymb}
 \usepackage{color}
@@ -40,7 +40,7 @@
 \newcommand\env[1]{\lit{#1}}
 \newcommand\opt[1]{\lit{#1}}
 \newcommand\meta[1]{$\langle$\textit{#1}$\rangle$}
-\newcommand\oarg[1]{\lit{[}\meta{#1}\lit{]}}
+\newcommand\oarg[1]{\lit[\meta{#1}\lit]}
 \newcommand\marg[1]{\lit{\{}\meta{#1}\lit{\}}}
 
 \newenvironment{csdoc}[1]{%
@@ -84,10 +84,10 @@ style of sequent calculus and related systems:
 
 \begin{example}{gobble=2}
   \begin{prooftree}
-    \Hypo{ \Gamma, A &\vdash B }
-    \Infer1[abs]{ \Gamma &\vdash A\to B }
-    \Hypo{ \Gamma \vdash A }
-    \Infer2[app]{ \Gamma \vdash B }
+    \hypo{ \Gamma, A &\vdash B }
+    \infer1[abs]{ \Gamma &\vdash A\to B }
+    \hypo{ \Gamma \vdash A }
+    \infer2[app]{ \Gamma \vdash B }
   \end{prooftree}
 \end{example}
 
@@ -107,7 +107,7 @@ starred variants.
     \cs{begin}\lit{\{prooftree\}}\oarg{options}
       \meta{statements}
     \cs{end}\lit{\{prooftree\}}}
-  Typeset the proof tree desribed by the \meta{statements}, as described in
+  Typeset the proof tree described by the \meta{statements}, as described in
   section~\ref{sec:statements}.
   The \meta{options} provide default formatting options for the proof tree.
   This environment can be used either in math mode or in text mode.
@@ -118,8 +118,8 @@ starred variants.
     \cs{begin}\lit{\{prooftree*\}}\oarg{options}
       \meta{statements}
     \cs{end}\lit{\{prooftree*\}}}
-  Typeset the proof centered on a line of its own; it is essentially
-  equivalent to wrapping the \env{prooftree} environment inside a \env{center}
+  Typeset the proof on a line of its own; it is essentially equivalent to
+  wrapping the \env{prooftree} environment inside a displayed math
   environment.
 \end{csdoc}
 
@@ -132,15 +132,15 @@ larger structure, like two parts of a formula:
 \begin{example}{gobble=2}
   \[
     \begin{prooftree}
-      \Hypo{ \vdash A }
-      \Hypo{ \vdash B } \Infer1{ \vdash B, C }
-      \Infer2{ \vdash A\wedge B, C }
+      \infer0{ \vdash A }
+      \hypo{ \vdash B } \infer1{ \vdash B, C }
+      \infer2{ \vdash A\wedge B, C }
     \end{prooftree}
     \quad \rightsquigarrow \quad
     \begin{prooftree}
-      \Hypo{ \vdash A } \Hypo{ \vdash B }
-      \Infer2{ \vdash A\wedge B }
-      \Infer1{ \vdash A\wedge B, C }
+      \infer0{ \vdash A } \hypo{ \vdash B }
+      \infer2{ \vdash A\wedge B }
+      \infer1{ \vdash A\wedge B, C }
     \end{prooftree}
   \]
 \end{example}
@@ -148,10 +148,10 @@ larger structure, like two parts of a formula:
 \section{Statements}
 \label{sec:statements}
 
-Statements describes proofs in postfix notation: when typesetting a proof tree
+Statements describe proofs in postfix notation: when typesetting a proof tree
 whose last rule has, say, two premisses, you will first write statements for
 the subtree of the first premiss, then statements for the subtree of the
-second premiss, then a statement like \cs{Infer2}\{\meta{conclusion}\} to
+second premiss, then a statement like \cs{infer2}\{\meta{conclusion}\} to
 build an inference with these two subtrees as premisses and the given text as
 conclusion.
 
@@ -160,17 +160,26 @@ At the beginning of a \lit{prooftree} environment, the stack is empty.
 At the end, it must contain exactly one tree, which is the one that will be
 printed.
 
+Note that the commands defined in this section only exist right inside
+\env{prooftree} environments.
+If you have a macro with the same name as one of the statements, for instance
+\cs{hypo}, then this macro will keep its meaning outside \env{prooftree}
+environments as well as inside the arguments of a statement.
+If you really need to access the statements in another context, you can can
+always call them by prefixing their names with \lit{ebproof}, for instance as
+\cs{ebproofhypo}.
+
 \subsection{Basic statements}
 
 The basic statements for building proofs are the following, where
 \meta{options} stands for arbitrary options as described in
 section~\ref{sec:options}.
-\begin{csdoc}{\cs{Hypo}\oarg{options}\marg{text}}
+\begin{csdoc}{\cs{hypo}\oarg{options}\marg{text}}
   Push a new proof tree consisting only in one conclusion line, with no
   premiss and no line above, in other words a tree with only a leaf
-  (\cs{Hypo} stands for \emph{hypothesis}).
+  (\cs{hypo} stands for \emph{hypothesis}).
 \end{csdoc}
-\begin{csdoc}{\cs{Infer}\oarg{options}\marg{arity}\oarg{label}\marg{text}}
+\begin{csdoc}{\cs{infer}\oarg{options}\marg{arity}\oarg{label}\marg{text}}
   Build an inference step by taking some proof trees from the top of the
   stack, assembling them with a rule joining their conclusions and putting a
   new conclusion below.
@@ -192,70 +201,92 @@ The position of the axis is deduced from the text of the conclusion at the
 root of the tree: if \meta{text} contains the alignment character \verb|&|
 then the axis is set at that position, otherwise the axis is set at the center
 of the conclusion text.
-The \cs{Infer} statement makes sure that the axis of the premiss is at the
+The \cs{infer} statement makes sure that the axis of the premiss is at the
 same position as the axis of the conclusion.
 If there are several premisses, it places the axis at the center between the
 left of the leftmost conclusion and the right of the rightmost conclusion:
 
 \begin{example}{gobble=2}
   \begin{prooftree}
-    \Hypo{ &\vdash A, B, C }
-    \Infer1{ A &\vdash B, C }
-    \Infer1{ A, B &\vdash C }
-    \Hypo{ D &\vdash E }
-    \Infer2{ A, B, D &\vdash C, E }
-    \Infer1{ A, B &\vdash C, D, E }
-    \Infer1{ A &\vdash B, C, D, E }
+    \hypo{ &\vdash A, B, C }
+    \infer1{ A &\vdash B, C }
+    \infer1{ A, B &\vdash C }
+    \hypo{ D &\vdash E }
+    \infer2{ A, B, D &\vdash C, E }
+    \infer1{ A, B &\vdash C, D, E }
+    \infer1{ A &\vdash B, C, D, E }
   \end{prooftree}
 \end{example}
 
-\subsection{Additional statements}
-
-The following additional statements may be used to affect the format of the
-last proof tree on the stack:
-
-\begin{csdoc}{\cs{Ellipsis}\marg{label}\marg{text}}
+\begin{csdoc}{\cs{ellipsis}\marg{label}\marg{text}}
   Typeset vertical dots, with a label on the right, and a new conclusion.
   No inference lines are inserted.
   \begin{example}{gobble=4}
     \begin{prooftree}
-      \Hypo{ \Gamma &\vdash A }
-      \Ellipsis{foo}{ \Gamma &\vdash A, B }
+      \hypo{ \Gamma &\vdash A }
+      \ellipsis{foo}{ \Gamma &\vdash A, B }
     \end{prooftree}
   \end{example}
 \end{csdoc}
 
-\begin{csdoc}{\cs{Alter}\marg{code}}
-  Modify the proof with arbitrary commands, assuming that these commands do
-  not affect the size.
-  The \meta{code} is executed in an \cs{hbox} and is followed by the insertion
-  of the actual box with the current sub-proof.
-  It is mostly useful with \cs{color} commands:
+
+\subsection{Modifying proof trees}
+
+The following additional statements may be used to affect the format of the
+last proof tree on the stack:
+
+\begin{csdoc}{\cs{rewrite}\marg{code}}
+  Rewrite the proof while preserving its size and alignment. The \meta{code}
+  is typeset in horizontal mode, with the following control sequences defined:
+  \begin{itemize}
+  \item \cs{treebox} is a box register that contains the original material,
+  \item \cs{treemark}\marg{name} expands as the position of a given mark with
+    respect to the left of the box.
+  \end{itemize}
+  A simple use of this statement is to change the color of a proof tree:
+  \begin{example}{gobble=4}
+    \begin{prooftree}
+      \hypo{ \Gamma, A &\vdash B }
+      \infer1[abs]{ \Gamma &\vdash A\to B }
+      \rewrite{\color{red}\box\treebox}
+      \hypo{ \Gamma \vdash A }
+      \infer2[app]{ \Gamma \vdash B }
+    \end{prooftree}
+  \end{example}
+  Note the absence of spaces inside the call to \cs{rewrite}, because spaces
+  would affect the position of the tree box.
+  Note also that explicit use of \cs{treebox} is required to actually draw the
+  subtree.
+  Not using it will effectively not render the subtree, while still reserving
+  its space in the enclosing tree:
   \begin{example}{gobble=4}
     \begin{prooftree}
-      \Hypo{ \Gamma, A &\vdash B }
-      \Infer1[abs]{ \Gamma &\vdash A\to B }
-      \Alter{\color{red}}
-      \Hypo{ \Gamma \vdash A }
-      \Infer2[app]{ \Gamma \vdash B }
+      \hypo{ \Gamma, A &\vdash B }
+      \infer1[abs]{ \Gamma &\vdash A\to B }
+      \rewrite{}
+      \hypo{ \Gamma \vdash A }
+      \infer2[app]{ \Gamma \vdash B }
     \end{prooftree}
   \end{example}
+  This kind of manipulation is useful for instance in conjunction with the
+  \package{beamer} package to allow revealing subtrees of a proof tree
+  progressively in successive slides of a given frame.
 \end{csdoc}
 
-\begin{csdoc}{\cs{Delims}\marg{left}\marg{right}}
+\begin{csdoc}{\cs{delims}\marg{left}\marg{right}}
   Put left and right delimiters around the whole sub-proof, without changing
   the alignment (the spacing is affected by the delimiters, however).
   The \meta{left} text must contain an opening occurrence of \cs{left} and the
   \meta{right} text must contain a matching occurrence of \cs{right}.
-  For instance, \verb|\Delims{\left(}{\right)}| will put the
+  For instance, \verb|\delims{\left(}{\right)}| will put the
   sub-proof between parentheses.
   \begin{example}{gobble=4}
     \begin{prooftree}
-      \Hypo{ A_1 \vee \cdots \vee A_n }
-      \Hypo{ [A_i] }
-      \Ellipsis{}{ B }
-      \Delims{ \left( }{ \right)_{1\leq i\leq n} }
-      \Infer2{ B }
+      \hypo{ A_1 \vee \cdots \vee A_n }
+      \hypo{ [A_i] }
+      \ellipsis{}{ B }
+      \delims{ \left( }{ \right)_{1\leq i\leq n} }
+      \infer2{ B }
     \end{prooftree}
   \end{example}
 \end{csdoc}
@@ -264,10 +295,8 @@ last proof tree on the stack:
 \label{sec:options}
 
 The formatting of trees, conclusion texts and inference rules is affected by
-options, specfied using the key-value system of PGF/TikZ, provided by the
-\package{pgfkeys} package.
-All options are in the \lit{/ebproof/} path in the key tree of
-\package{pgfkeys}.
+options, specified using the \LaTeX3 key-value system.
+All options are in the \lit{ebproof} module in the key tree.
 They can be set locally for a proof tree or for a single statement using
 optional arguments in the associated commands.
 
@@ -297,10 +326,10 @@ behaviour.
     Proof trees grow downwards, with conclusions above and premisses below.
     \begin{example}{gobble=4}
       \begin{prooftree}[proof style=downwards]
-        \Hypo{ \Gamma, A &\vdash B }
-        \Infer1[abs]{ \Gamma &\vdash A\to B }
-        \Hypo{ \Gamma \vdash A }
-        \Infer2[app]{ \Gamma \vdash B }
+        \hypo{ \Gamma, A &\vdash B }
+        \infer1[abs]{ \Gamma &\vdash A\to B }
+        \hypo{ \Gamma \vdash A }
+        \infer2[app]{ \Gamma \vdash B }
       \end{prooftree}
     \end{example}
   \end{csdoc}
@@ -319,12 +348,12 @@ For instance, the first line of the example above could be written
   The default value is \lit{true}.
   \begin{example}{gobble=4}
     \begin{prooftree}[center=false]
-      \Infer0{ A \vdash A }
+      \infer0{ A \vdash A }
     \end{prooftree}
     \qquad
     \begin{prooftree}[center=false]
-      \Hypo{ \Gamma, A \vdash B }
-      \Infer1{ \Gamma \vdash A \to B }
+      \hypo{ \Gamma, A \vdash B }
+      \infer1{ \Gamma \vdash A \to B }
     \end{prooftree}
   \end{example}
 \end{csdoc}
@@ -336,9 +365,9 @@ For instance, the first line of the example above could be written
   The default value is \lit{1.5em}.
   \begin{example}{gobble=4}
     \begin{prooftree}[separation=0.5em]
-      \Hypo{ A } \Hypo{ B } \Infer2{ C }
-      \Hypo{ D } \Hypo{ E } \Hypo{ F } \Infer3{ G }
-      \Hypo{ H } \Infer[separation=3em]3{ K }
+      \hypo{ A } \hypo{ B } \infer2{ C }
+      \hypo{ D } \hypo{ E } \hypo{ F } \infer3{ G }
+      \hypo{ H } \infer[separation=3em]3{ K }
     \end{prooftree}
   \end{example}
 \end{csdoc}
@@ -348,10 +377,10 @@ For instance, the first line of the example above could be written
   The default value is \lit{0.7ex}.
   \begin{example}{gobble=4}
     \begin{prooftree}[rule margin=2ex]
-      \Hypo{ \Gamma, A &\vdash B }
-      \Infer1[abs]{ \Gamma &\vdash A\to B }
-      \Hypo{ \Gamma \vdash A }
-      \Infer2[app]{ \Gamma \vdash B }
+      \hypo{ \Gamma, A &\vdash B }
+      \infer1[abs]{ \Gamma &\vdash A\to B }
+      \hypo{ \Gamma \vdash A }
+      \infer2[app]{ \Gamma \vdash B }
     \end{prooftree}
   \end{example}
 \end{csdoc}
@@ -377,24 +406,25 @@ For instance, the first line of the example above could be written
   \end{csdoc}
   The precise rendering is influenced by parameters specified below.
   Arbitrary new shapes can defined using the \lit{rule code} option described
-  afterwards.
+  below and the \cs{ebproofnewrulestyle} command described in
+  section~\ref{sec:styles}.
 \end{csdoc}
 
-In the optional argument of the \cs{Infer} statement, rule styles can be
+In the optional argument of the \cs{infer} statement, rule styles can be
 specified directly, without prefixing the style name by ``\lit{rule style=}''.
-For instance, \cs{Infer}\lit{[dashed]} is equivalent to
-\cs{Infer}\lit{[rule style=dashed]}.
+For instance, \cs{infer}\lit{[dashed]} is equivalent to
+\cs{infer}\lit{[rule style=dashed]}.
 
 \begin{example}{gobble=2}
   \begin{prooftree}
-    \Hypo{ \Gamma &\vdash A \to B }
-    \Infer[no rule]1{ \Gamma &\vdash {!A} \multimap B }
-    \Hypo{ \Delta &\vdash A }
-    \Infer[rule thickness=2pt]1{ \Delta &\vdash {!A} }
-    \Infer0{ B \vdash B }
-    \Infer[dashed]2{ \Delta, {!A}\multimap B \vdash B }
-    \Infer2{ \Gamma, \Delta &\vdash B }
-    \Infer[double]1{ \Gamma \cup \Delta &\vdash B }
+    \hypo{ \Gamma &\vdash A \to B }
+    \infer[no rule]1{ \Gamma &\vdash {!A} \multimap B }
+    \hypo{ \Delta &\vdash A }
+    \infer[rule thickness=2pt]1{ \Delta &\vdash {!A} }
+    \infer0{ B \vdash B }
+    \infer[dashed]2{ \Delta, {!A}\multimap B \vdash B }
+    \infer2{ \Gamma, \Delta &\vdash B }
+    \infer[double]1{ \Gamma \cup \Delta &\vdash B }
   \end{prooftree}
 \end{example}
 
@@ -426,34 +456,16 @@ For instance, \cs{Infer}\lit{[dashed]} is equivalent to
     \begin{prooftree}[rule code={\hbox{\tikz
         \draw[decorate,decoration={snake,amplitude=.3ex}]
         (0,0) -- (\hsize,0);}}]
-      \Hypo{ \Gamma &\vdash A }
-      \Infer1{ \Gamma &\vdash A, \ldots, A }
-      \Hypo{ \Delta, A, \ldots, A \vdash \Theta }
-      \Infer2{ \Gamma, \Delta \vdash \Theta }
+      \hypo{ \Gamma &\vdash A }
+      \infer1{ \Gamma &\vdash A, \ldots, A }
+      \hypo{ \Delta, A, \ldots, A \vdash \Theta }
+      \infer2{ \Gamma, \Delta \vdash \Theta }
     \end{prooftree}
   \end{example}
   Note that this example requires the \package{tikz} package, with the
   \package{decorations.pathmorphing} library for the \lit{snake} decoration.
 \end{csdoc}
 
-The option \opt{rule code} is particularly useful in a ``styles'' in the sense of
-\package{pgfkeys} as it allows to define new rule styles.
-The allowed values for \opt{rule style} are actually defined this way.
-The above example could be turned into a new rule style \lit{zigzag} with the
-following command:
-\begin{example}{gobble=2}
-  \ebproofset{
-    rule style/zigzag/.style={rule code={\hbox{\tikz
-      \draw[decorate,decoration={snake,amplitude=.3ex}]
-      (0,0) -- (\hsize,0);}}}}
-  \begin{prooftree}
-    \Hypo{ \Gamma &\vdash A }
-    \Infer1{ \Gamma &\vdash A, \ldots, A }
-    \Hypo{ \Delta, A, \ldots, A \vdash \Theta }
-    \Infer[zigzag]2{ \Gamma, \Delta \vdash \Theta }
-  \end{prooftree}
-\end{example}
-
 \subsection{Format of conclusions}
 
 \begin{csdoc}{%
@@ -462,8 +474,8 @@ following command:
     \opt{right template=}\meta{code}}
   Defines how conclusions are formatted.
   The code is arbitrary \TeX\ code, composed in horizontal mode.
-  The macro \cs{inserttext} can be used inside the actual text passed to the
-  \cs{Hypo} and \cs{Infer} statements.
+  The macro \cs{inserttext} is used to insert the actual text passed to the
+  \cs{hypo} and \cs{infer} statements.
   The \opt{template} value is used for conclusions with no alignment mark.
   The \opt{left template} and \opt{right template} values are used on the left
   and right side of the alignment mark when it is present.
@@ -471,14 +483,14 @@ following command:
   conclusions are set in math mode.
   The default values for \opt{left template} and \opt{right template} are
   similar, with spacing assuming that a relation symbol is put near the
-  alignment mark, so that \verb|\Infer1{A &\vdash B}| is spaced correctly.
+  alignment mark, so that \verb|\infer1{A &\vdash B}| is spaced correctly.
 
   \begin{example}{gobble=4}
     \begin{prooftree}[template=(\textbf\inserttext)]
-      \Hypo{ foo }
-      \Hypo{ bar }
-      \Infer1{ baz }
-      \Infer2{ quux }
+      \hypo{ foo }
+      \hypo{ bar }
+      \infer1{ baz }
+      \infer2{ quux }
     \end{prooftree}
   \end{example}
 \end{csdoc}
@@ -490,8 +502,18 @@ following command:
     \opt{right label=}\meta{text}}
   The text to use as the labels of the rules, on the left and on the right
   of the inference line.
-  Using the second optional argument in \cs{Infer} is equivalent to setting
+  Using the second optional argument in \cs{infer} is equivalent to setting
   the \env{right label} option with the value of that argument.
+
+  \begin{example}{gobble=4}
+    \begin{prooftree}
+      \hypo{ \Gamma, A &\vdash B }
+      \infer[left label=$\lambda$]1[abs]
+        { \Gamma &\vdash A\to B }
+      \hypo{ \Gamma \vdash A }
+      \infer[left label=@]2[app]{ \Gamma \vdash B }
+    \end{prooftree}
+  \end{example}
 \end{csdoc}
 \begin{csdoc}{%
     \opt{left label template=}\meta{code} \\
@@ -508,6 +530,60 @@ following command:
   The spacing between an inference lines and its labels.
   The default value is \lit{0.5em}.
 \end{csdoc}
+\begin{csdoc}{\opt{label axis=}\meta{dimension}}
+  The height of the horizontal axis used for aligning the labels with the
+  rules. The default value is \lit{0.5ex}.
+\end{csdoc}
+
+
+\subsection{Style macros}
+\label{sec:styles}
+
+The following commands allow for the definition of custom styles using the
+basic style options, in a way similar to PGF's ``styles'' and \LaTeX3's
+``meta-keys''.
+This allows setting a bunch of options with the same values in many proofs
+using a single definition.
+
+\begin{csdoc}{\cs{ebproofnewstyle}\marg{name}\marg{options}}
+  Define a new style option \meta{name} that sets the given \meta{options}.
+
+  For instance, the following code defines a new option \opt{small} that sets
+  various parameters so that proofs are rendered smaller.
+  \begin{example}{gobble=4}
+    \ebproofnewstyle{small}{
+      separation = 1em, rule margin = .5ex,
+      template = \footnotesize$\inserttext$ }
+    \begin{prooftree}[small]
+      \hypo{ \Gamma, A \vdash B }
+      \infer1{ \Gamma \vdash A\to B }
+      \hypo{ \Gamma \vdash A } \infer2{ \Gamma \vdash B }
+    \end{prooftree}
+  \end{example}
+\end{csdoc}
+
+\begin{csdoc}{\cs{ebproofnewrulestyle}\marg{name}\marg{options}}
+  Define a new rule style.
+  The \meta{options} part includes options used to set how to draw rules in
+  the new style.
+
+  The option \opt{rule code} is useful in this command as it allows to
+  define arbitrary rule styles.
+  For instance, the squiggly rule example above could be turned into a new
+  rule style \lit{zigzag} with the following code:
+  \begin{example}{gobble=4}
+    \ebproofnewrulestyle{zigzag}{
+      rule code = {\hbox{\tikz
+        \draw[decorate,decoration={snake,amplitude=.3ex}]
+        (0,0) -- (\hsize,0);}}}
+    \begin{prooftree}
+      \hypo{ \Gamma &\vdash A }
+      \infer1{ \Gamma &\vdash A, \ldots, A }
+      \hypo{ \Delta, A, \ldots, A \vdash \Theta }
+      \infer[zigzag]2{ \Gamma, \Delta \vdash \Theta }
+    \end{prooftree}
+  \end{example}
+\end{csdoc}
 
 
 \section{License}
@@ -528,4 +604,35 @@ The Current Maintainer of this work is Emmanuel Beffara.
 
 This work consists of the files \texttt{ebproof.sty} and \texttt{ebproof.tex}.
 
+
+\section{History}
+
+This section lists the principal evolutions of the package, in reverse
+chronological order.
+\begin{description}
+\item[Version 2.0]
+  A complete rewrite of the code using the \LaTeX3 programming environment. 
+  The incompatible changes from the user's point of view are the following:
+  \begin{itemize}
+  \item Proof statements are now writtten in lowercase ({i.e.} \cs{Infer} is
+    now written \cs{infer} etc.) but the syntax is otherwise unchanged.
+    The old uppercase commands still work but produce a deprecation warning,
+    they will be removed in a future version.
+  \item New styles are now defined using \cs{ebproofnewstyle} and
+    \cs{ebproofnewrulestyle}. The previous method using PGF styles does not
+    work anymore (because PGF is not used anymore).
+  \end{itemize}
+  The new commands and options are the following:
+  \begin{itemize}
+  \item The statement \cs{rewrite} generalizes \cs{Alter},
+  \item The option \opt{label axis} controls vertical alignment of labels.
+  \end{itemize}
+\item[Version 1.1]
+  A bugfix release.
+  In \opt{template} options, one now uses \cs{inserttext} instead of \lit{\#1}
+  for the text arguments, which improves robustness.
+\item[Version 1.0]
+  The first public release.
+\end{description}
+
 \end{document}
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