Author: larry Date: Sat Nov 4 09:29:42 2006 New Revision: 13414 Modified: doc/trunk/design/syn/S02.pod
Log: Clarified that ordering of grammatical categories is controlled by the magical hash matching construct. Modified: doc/trunk/design/syn/S02.pod ============================================================================== --- doc/trunk/design/syn/S02.pod (original) +++ doc/trunk/design/syn/S02.pod Sat Nov 4 09:29:42 2006 @@ -12,9 +12,9 @@ Maintainer: Larry Wall <[EMAIL PROTECTED]> Date: 10 Aug 2004 - Last Modified: 9 Oct 2006 + Last Modified: 4 Nov 2006 Number: 2 - Version: 76 + Version: 77 This document summarizes Apocalypse 2, which covers small-scale lexical items and typological issues. (These Synopses also contain @@ -2324,11 +2324,27 @@ At each point in the parse, the lexer knows which subset of the grammatical categories are possible at that point, and follows the longest-token rule across all the active grammatical categories. -(Ordering of grammatical categories matters only in case of a "tie", -in which case the grammatical category that is notionally "first" -in the grammar wins. For instance, a statement_control is always going to win out over a prefix operator of the same name. More specifically, you can't -call a function named "if" directly because it would be hidden either -by the statement_control category or the statement_modifier category.) +The grammatical categories that are active at any point are specified +using a regex construct involving a set of magical hashes. For example, +the matcher for the beginning of a statement might look like: + + <%statement_control + | %scope_declarator + | %prefix + | %prefix_circumfix_meta_operator + | %circumfix + | %quote + | %term + > + +(Ordering of grammatical categories within such a construct matters +only in case of a "tie", in which case the grammatical category that +is notionally "first" wins. For instance, given the example above, a +statement_control is always going to win out over a prefix operator of +the same name. And the reason you can't call a function named "if" +directly because it would be hidden either by the statement_control +category at the beginning of a statement or the statement_modifier +category elsewhere in the statement.) Here are the current grammatical categories:
