</variablelist>
</para>
</sect1>
- <sect1 id="tac_discriminate">
- <title>discriminate</title>
- <titleabbrev>discriminate</titleabbrev>
- <para><userinput>discriminate p</userinput></para>
+ <sect1 id="tac_destruct">
+ <title>destruct</title>
+ <titleabbrev>destruct</titleabbrev>
+ <para><userinput>destruct p</userinput></para>
<para>
<variablelist>
<varlistentry role="tactic.synopsis">
<term>Synopsis:</term>
<listitem>
- <para><emphasis role="bold">discriminate</emphasis> &sterm;</para>
+ <para><emphasis role="bold">destruct</emphasis> &sterm;</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Pre-conditions:</term>
<listitem>
- <para><command>p</command> must have type <command>K t<subscript>1</subscript> ... t<subscript>n</subscript> = K' t'<subscript>1</subscript> ... t'<subscript>m</subscript></command> where <command>K</command> and <command>K'</command> must be different constructors of the same inductive type and each argument list can be empty if
-its constructor takes no arguments.</para>
+ <para><command>p</command> must have type <command>E<subscript>1</subscript> = E<subscript>2</subscript></command> where the two sides of the equality are possibly applied constructors of an inductive type.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Action:</term>
<listitem>
- <para>It closes the current sequent by proving the absurdity of
- <command>p</command>.</para>
+ <para>The tactic recursively compare the two sides of the equality
+ looking for different constructors in corresponding position.
+ If two of them are found, the tactic closes the current sequent
+ by proving the absurdity of <command>p</command>. Otherwise
+ it adds a new hypothesis for each leaf of the formula that
+ states the equality of the subformulae in the corresponding
+ positions on the two sides of the equality.
+ </para>
</listitem>
</varlistentry>
<varlistentry>
</variablelist>
</para>
</sect1>
- <sect1 id="tac_injection">
- <title>injection</title>
- <titleabbrev>injection</titleabbrev>
- <para><userinput>injection p</userinput></para>
- <para>
- <variablelist>
- <varlistentry role="tactic.synopsis">
- <term>Synopsis:</term>
- <listitem>
- <para><emphasis role="bold">injection</emphasis> &sterm;</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>Pre-conditions:</term>
- <listitem>
- <para><command>p</command> must have type <command>K t<subscript>1</subscript> ... t<subscript>n</subscript> = K t'<subscript>1</subscript> ... t'<subscript>n</subscript></command> where both argument lists are empty if
-<command>K</command> takes no arguments.</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>Action:</term>
- <listitem>
- <para>It derives new hypotheses by injectivity of
- <command>K</command>.</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>New sequents to prove:</term>
- <listitem>
- <para>The new sequent to prove is equal to the current sequent
- with the additional hypotheses
- <command>t<subscript>1</subscript>=t'<subscript>1</subscript></command> ... <command>t<subscript>n</subscript>=t'<subscript>n</subscript></command>.</para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </sect1>
<sect1 id="tac_intro">
<title>intro</title>
<titleabbrev>intro</titleabbrev>
</variablelist>
</para>
</sect1>
+
+ <sect1 id="tac_subst">
+ <title>subst</title>
+ <titleabbrev>subst</titleabbrev>
+ <para><userinput>subst</userinput></para>
+ <para>
+ <variablelist>
+ <varlistentry role="tactic.synopsis">
+ <term>Synopsis:</term>
+ <listitem>
+ <para><emphasis role="bold">subst</emphasis></para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Pre-conditions:</term>
+ <listitem><para>
+ None.
+ </para></listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Action:</term>
+ <listitem><para>
+ For each premise of the form
+ <command>H: x = t</command> or <command>H: t = x</command>
+ where <command>x</command> is a local variable and
+ <command>t</command> does not depend on <command>x</command>,
+ the tactic rewrites <command>H</command> wherever
+ <command>x</command> appears clearing <command>H</command> and
+ <command>x</command> afterwards.
+ </para></listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>New sequents to prove:</term>
+ <listitem><para>
+ The one opened by the applied tactics.
+ </para></listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </sect1>
<sect1 id="tac_symmetry">
<title>symmetry</title>
<titleabbrev>symmetry</titleabbrev>