</sect1>
<sect1 id="command_coercion">
<title>coercion</title>
- <para><userinput>coercion u</userinput></para>
+ <para><userinput>coercion u with ariety saturation nocomposites</userinput></para>
<para>
<variablelist>
<varlistentry>
<term>Synopsis:</term>
<listitem>
- <para><emphasis role="bold">coercion</emphasis> &uri;</para>
+ <para>
+ <emphasis role="bold">coercion</emphasis>
+ (&uri; | &term; <emphasis role="bold">with</emphasis>)
+ [ &nat; [&nat;]]
+ [ <emphasis role="bold">nocomposites</emphasis> ]
+ </para>
</listitem>
</varlistentry>
<varlistentry>
<term>Action:</term>
<listitem>
- <para>Declares <command>u</command> as an implicit coercion
- from the type of its last argument (source)
- to its codomain (target). Every time a term <command>x</command>
+ <para>Declares <command>u</command> as an implicit coercion.
+ If the type of <command>u</command> is
+ <command>∀x1:T1. … ∀x(n-1):T(n-1).Tn</command> the coercion target is
+ <command>T(n - ariety)</command> while its source is
+ <command>T(n - ariety - saturation - 1)</command>.
+ Every time a term <command>x</command>
of type source is used with expected type target, Matita
automatically replaces <command>x</command> with
- <command>(u ? … ? x)</command> to avoid a typing error.</para>
+ <command>(u ? … ? x ? … ?)</command> to avoid a typing error.</para>
+ Note that the number of <command>?</command> added after
+ <command>x</command> is saturation.
<para>Implicit coercions are not displayed to the user:
<command>(u ? … ? x)</command> is rendered simply
as <command>x</command>.</para>
and there is already a coercion <command>u'</command> of
target <command>s</command> or source <command>t</command>,
a composite implicit coercion is automatically computed
- by Matita.</para>
+ by Matita unless <emphasis role="bold">nocomposites</emphasis>
+ is specified.</para>
</listitem>
</varlistentry>
</variablelist>