explain differences in conditionals/while

Author: TimToady

lib/Language/5to6.pod

@@ -595,7 +595,15 @@ I<Deleting an element in a hash>
 
 =head4 C<if> C<elsif> C<else> C<unless>
 
-Unchanged; parens around the conditions are now optional.
+Mostly unchanged; parens around the conditions are now optional, but if
+used, must not immediately follow the keyword, or it will be taken as a function
+call instead.  Binding the conditional expression to a value is also a little different:
+
+    if (my $x = dostuff()) {...}  # Perl 5
+    if dostuff() -> $x {...}      # Perl 6
+
+(You can still use the C<my> form in Perl 6, but it will scoped to the
+outer block, not the inner.)
 
 =head4 C<given> C<when>
 
@@ -607,7 +615,15 @@ See also the warnings on the smart-match op above.
 
 =head4 C<while> C<until>
 
-Unchanged; parens around the conditions are now optional.
+Mostly unchanged; parens around the conditions are now optional, but if
+used, must not immediately follow the keyword, or it will be taken as a function
+call instead.  Binding the conditional expression to a value is also a little different:
+
+    while (my $x = dostuff()) {...}  # Perl 5
+    while dostuff() -> $x {...}      # Perl 6
+
+(You can still use the C<my> form in Perl 6, but it will scoped to the
+outer block, not the inner.)
 
 Note that reading line-by-line from a filehandle has changed.