Provide a practical example of interpolating package names

doc/Language/packages.pod6

@@ -257,6 +257,50 @@ go into that package by default. Process-wide variables live in the
 C<PROCESS> package. Most predefined globals such as C<$*UID> and C<$*PID>
 are actually process globals.
 
+=head1 Programmatic use of modules
+
+It is sometimes useful to be able to programmatically define and use modules.
+Here is a practical example.
+
+Assume we have a series of modules with the modules files in a directory
+tree like this:
+
+=begin code
+lib/
+    TomtomMaps/
+        EG/
+            # a directory of modules created from the Tomtom Maps SDK
+            A01.rakumod
+            #..l
+            C09.rakumod
+=end code
+
+Module C<TomtomMaps::EG::C09> looks like this:
+
+=begin code
+unit module TomtomMaps::EG::C09;
+# ensure you use the 'our' 
+our sub print-example($fp, :$api-maps-key) { # do not need to export the sub
+    $fp.print: qq:to/HERE/;
+    # ... the example html file
+    HERE
+}
+=end code
+
+We can access and use the subroutines like this:
+
+=begin code
+my $module-dir = 'TomtomMaps::EG';
+my $module     = 'C09';
+my $m          = "{$module-dir}::{$module}";
+
+# you must use the run-time statement, not the compile-time 'use'
+require ::($m); 
+
+# execute the subroutine
+&::($m)::print-example($fp, :$api-maps-key); # the map's html file is written
+=end code
+
 =end pod
 
 # vim: expandtab softtabstop=4 shiftwidth=4 ft=perl6