🐛 closes Raku#4012

doc/Type/Signature.pod6

@@ -187,9 +187,10 @@ parameter by name, for instance to distinguish between different signatures in a
 L<multi|/language/functions#index-entry-declarator_multi-Multi-dispatch> or to
 check the signature of a L<Callable|/type/Callable>.
 
-    my $sig = :($, @, %a);          # two anonymous and a "normal" parameter
-    $sig = :(Int, Positional);      # just a type is also fine (two parameters)
-    sub baz(Str) { "Got passed a Str" }
+=for code :preamble<my $sig;>
+my $sig = :($, @, %a);          # two anonymous and a "normal" parameter
+$sig = :(Int, Positional);      # just a type is also fine (two parameters)
+sub baz(Str) { "Got passed a Str" }
 
 Type constraints may also be L<type captures|/type/Signature#Type_captures>.
 
@@ -842,10 +843,11 @@ positional, except slurpy hash and arguments marked with a leading colon C<:>.
 The latter is called a L<colon-pair|/type/Pair>. Check the following signatures
 and what they denote:
 
-    $sig1 = :($a);               # a positional argument
-    $sig2 = :(:$a);              # a named argument of name 'a'
-    $sig3 = :(*@a);              # a slurpy positional argument
-    $sig4 = :(*%h);              # a slurpy named argument
+=for code :preamble<my ($sig1, $sig2, $sig3, $sig4);>
+$sig1 = :($a);               # a positional argument
+$sig2 = :(:$a);              # a named argument of name 'a'
+$sig3 = :(*@a);              # a slurpy positional argument
+$sig4 = :(*%h);              # a slurpy named argument
 
 On the caller side, positional arguments are passed in the same order as the
 arguments are declared.
@@ -961,23 +963,27 @@ X<|optional argument>
 Positional parameters are mandatory by default, and can be made optional
 with a default value or a trailing question mark:
 
-    $sig1 = :(Str $id);         # required parameter
-    $sig2 = :($base = 10);      # optional parameter, default value 10
-    $sig3 = :(Int $x?);         # optional parameter, default is the Int type object
+=for code :preamble<my ($sig1, $sig2, $sig3);>
+$sig1 = :(Str $id);         # required parameter
+$sig2 = :($base = 10);      # optional parameter, default value 10
+$sig3 = :(Int $x?);         # optional parameter, default is the Int type object
 
 X<|mandatory named argument>
 Named parameters are optional by default, and can be made mandatory with a
 trailing exclamation mark:
 
-    $sig1 = :(:%config);        # optional parameter
-    $sig2 = :(:$debug = False); # optional parameter, defaults to False
-    $sig3 = :(:$name!);         # mandatory 'name' named parameter
+=for code :preamble<my ($sig1, $sig2, $sig3);>
+$sig1 = :(:%config);        # optional parameter
+$sig2 = :(:$debug = False); # optional parameter, defaults to False
+$sig3 = :(:$name!);         # mandatory 'name' named parameter
 
 Default values can depend on previous parameters, and are (at least
 notionally) computed anew for each call
 
-    $sig1 = :($goal, $accuracy = $goal / 100);
-    $sig2 = :(:$excludes = ['.', '..']);        # a new Array for every call
+=begin code :preamble<my ($sig1, $sig2);>
+$sig1 = :($goal, $accuracy = $goal / 100);
+$sig2 = :(:$excludes = ['.', '..']);        # a new Array for every call
+=end code
 
 =head2 Dynamic variables