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| -rw-r--r-- | docs/users_guide/ghci.xml | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/docs/users_guide/ghci.xml b/docs/users_guide/ghci.xml index c5b5f7c19f..299b1e5bb2 100644 --- a/docs/users_guide/ghci.xml +++ b/docs/users_guide/ghci.xml @@ -616,6 +616,41 @@ Prelude IO> </para> <sect3> + <title><literal>:module</literal> and + <literal>:load</literal></title> + + <para>It might seem that <literal>:module</literal> and + <literal>:load</literal> do similar things: you can use both + to bring a module into scope. However, there is a clear + difference. GHCi is concerned with two sets of modules:</para> + + <itemizedlist> + <listitem> + <para>The set of modules that are + currently <emphasis>loaded</emphasis>. This set is + modified + by <literal>:load</literal>, <literal>:add</literal> + and <literal>:reload</literal>. + </para> + </listitem> + <listitem> + <para>The set of modules that are currently <emphasis>in + scope</emphasis> at the prompt. This set is modified + by <literal>:module</literal>, and it is also set + automatically + after <literal>:load</literal>, <literal>:add</literal>, + and <literal>:reload</literal>.</para> + </listitem> + </itemizedlist> + + <para>You cannot add a module to the scope if it is not + loaded. This is why trying to + use <literal>:module</literal> to load a new module results + in the message “<literal>module M is not + loaded</literal>”.</para> + </sect3> + + <sect3> <title>Qualified names</title> <para>To make life slightly easier, the GHCi prompt also |