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Diffstat (limited to 'doc/manual/usermanual.xml')
| -rw-r--r-- | doc/manual/usermanual.xml | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/doc/manual/usermanual.xml b/doc/manual/usermanual.xml index cdd05998a..c3403449f 100644 --- a/doc/manual/usermanual.xml +++ b/doc/manual/usermanual.xml @@ -89,6 +89,11 @@ share common metadata between many packages.</para></listitem> <para>This results in <varname>A</varname> containing <literal>aval</literal> and <varname>B</varname> containing <literal>preavalpost</literal>.</para> </section> <section> + <title>Setting a default value (?=)</title> + <para><screen><varname>A</varname> ?= "aval"</screen></para> + <para>If <varname>A</varname> is set before the above is called, it will retain it's previous value. If <varname>A</varname> is unset prior to the above call, <varname>A</varname> will be set to <literal>aval</literal>.</para> + </section> + <section> <title>Immediate variable expansion (:=)</title> <para>:= results in a variable's contents being expanded immediately, rather than when the variable is actually used.</para> <para><screen><varname>T</varname> = "123" |