Author: larry Date: Sun Jan 7 01:39:34 2007 New Revision: 13516 Modified: doc/trunk/design/syn/S03.pod
Log: Clarification on how a Grammar pattern finds its top rule. Modified: doc/trunk/design/syn/S03.pod ============================================================================== --- doc/trunk/design/syn/S03.pod (original) +++ doc/trunk/design/syn/S03.pod Sun Jan 7 01:39:34 2007 @@ -12,9 +12,9 @@ Maintainer: Larry Wall <[EMAIL PROTECTED]> Date: 8 Mar 2004 - Last Modified: 6 Jan 2007 + Last Modified: 7 Jan 2007 Number: 3 - Version: 84 + Version: 85 =head1 Changes to Perl 5 operators @@ -756,8 +756,15 @@ If the redefinition occurs at compile time prior to analysis of the smart match then the information is also available to the optimizer.) -Matching against a C<Grammar> object will call the first rule defined -in the grammar. +Matching against a C<Grammar> object will call the C<top> method +defined in the grammar. The C<top> method may either be a rule +itself, or may call the actual top rule automatically. How the +C<Grammar> determines the top rule is up to the grammar, but normal +Perl 6 grammars will default to setting top to the first rule in the +original base grammar. Derived grammars then inherit this idea of +the top rule. This may be overridden in either the base grammar or a +derived grammer by explicitly naming a rule "top", or defining your +own top method to call some other rule. Matching against a C<Signature> does not actually bind any variables, but only tests to see if the signature I<could> bind. To really bind
