[basics] be more verbose about interpolation of arrays and hashes; mo…

…re examples

src/basics.pod

@@ -442,33 +442,58 @@ X<strings; single-quoted>
 Double quoted strings in Perl 6 can interpolate variables with the C<$>
 sigil as well as blocks of code in curly braces. Since any arbitrary
 Perl code can appear within curly braces, C<Array>s and C<Hash>es may be
-interpolated by placing them within curly bracesN<There is another
-interpolation method known as the I<M<zen slice>>. If an array name is
-followed by empty subscripts within the double quoted string (i.e. C<say
-"@array[]";>), then the array is interpolated as a space separated list.
-Similarly, if a hash is followed by empty subscripts (i.e. C<say
-"%h{}">) then the C<Hash> is interpolated as a space separated list of
-values. The keys of the C<Hash> are not interpolated.>. C<Arrays> within
+interpolated by placing them within curly braces.
+
+
+Arrays within
 curly braces are interpolated with a single space character between each
-item. C<Hash>es within curly braces are interpolated as a series of
+item. Hashes within curly braces are interpolated as a series of
 lines. Each line will contain a key, followed by a tab character, then
 the value associated with that key, and finally a newline.
 
 =begin programlisting
 
-    say "Math: { 1 + 2 }"                   # Math: 3
-    my @people = <Luke Matthew Mark>;
-    say "The synoptics are: {@people}"      # The synoptics are: Luke Matthew Mark
+ say "Math: { 1 + 2 }"                   # Math: 3
+ my @people = <Luke Matthew Mark>;
+ say "The synoptics are: {@people}"      # The synoptics are: Luke Matthew Mark
+
+ say "{%sets}";                          # From the table tennis tournament
+
+ # Charlie 4
+ # Dave    6
+ # Ana     8
+ # Beth    4
+
+=end programlisting
+
+
+When array and hash variables appear directly in a double-quoted string (and
+not inside curly brackets), they are only interpolated if their name is
+followed by a postcircumfix -- a bracketing pair that follows a
+statement. It's also ok to have a method call between the variable name and
+the postcircumfix.
+
+X<Zen slice>
+
+=begin programlisting
+
+ my @flavours = <vanilla peach>;
+
+ say "we have @flavours";           # we have @flavours
+ say "we have @flavours[0]";        # we have vanilla
+ # so-called "Zen slice"
+ say "we have @flavours[]";         # we have vanilla peach
 
-    say "{%sets}";                          # From the tennis tournament
+ # method calls ending in postcircumfix
+ say "we have @flavours.sort()";    # we have peach vanilla
 
-    # Charlie 4
-    # Dave    6
-    # Ana     8
-    # Beth    4
+ # chained method calls:
+ say "we have @flavours.sort.join(', ')";
+                                    # we have peach, vanilla
 
 =end programlisting
 
+
 =head1 Exercises
 
 B<1.> The input format of the example program is redundant: the first line