hints

diff --git a/matita/matita/help/C/sec_commands.xml b/matita/matita/help/C/sec_commands.xml
index 2e5995d98901a3c61fbfe1e889bba7b664130b3c..6c9ad43af74097f740569d63d827fbf3424fbd96 100644 (file)
--- a/matita/matita/help/C/sec_commands.xml
+++ b/matita/matita/help/C/sec_commands.xml
@@ -502,46 +502,34 @@
  </sect1>
  <sect1 id="command_unification_hint">
    <title>unification hint</title>
-   <para>TODO</para>
-   <!--
-   <para><userinput>coercion u with ariety saturation nocomposites</userinput></para>
+   <para><userinput>unification hint n ≔ v1 : T1,… vi : Ti; h1 ≟ t1, …  hn ≟ tn ⊢ tl ≡ tr.</userinput></para>
    <para>
      <variablelist>
        <varlistentry>
          <term>Synopsis:</term>
          <listitem>
                 <para>
-                        <emphasis role="bold">coercion</emphasis> 
-                        (&uri; | &term; <emphasis role="bold">with</emphasis>)
-                        [ &nat; [&nat;]] 
-                        [ <emphasis role="bold">nocomposites</emphasis> ]
+                        <emphasis role="bold">unification hint</emphasis> 
+                        &nat;
+                        <emphasis role="bold">≔</emphasis>
+                        [ &id; [ <emphasis role="bold">:</emphasis> &term; ] ,.. ]
+                        <emphasis role="bold">;</emphasis>
+                        [ &id; <emphasis role="bold">≟</emphasis> &term; ,.. ]
+                        <emphasis role="bold">⊢</emphasis>
+                        &term; <emphasis role="bold">≡</emphasis> &term;
                 </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>Action:</term>
          <listitem>
-                <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>
-            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>
-           <para>When a coercion <command>u</command> is declared
-            from source <command>s</command> to target <command>t</command>
-            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 unless <emphasis role="bold">nocomposites</emphasis> 
-           is specified.</para>
+                <para>Declares the hint at precedence <command>n</command></para>
+                <para>The file <command>hints_declaration.ma</command> must be
+                        included to declare hints with that syntax.</para>
+                <para>Unification hints are described in the paper
+                        &quot;Hints in unification&quot; by
+                        Asperti, Ricciotti, Sacerdoti and Tassi.
+                </para>
          </listitem>
        </varlistentry>
      </variablelist>