added expr.c, which has some thoughts on expression implementation

1 files changed, 40 insertions, 0 deletions

diff --git a/expr.c b/expr.c
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+/* expr.c - an expression class.
+ * This module contains all code needed to represent expressions. Most
+ * importantly, that means code to parse and execute them. Expressions
+ * heavily depend on (loadable) functions, so it works in conjunction
+ * with the function manager.
+ *
+ * Module begun 2007-11-30 by Rainer Gerhards
+ *
+ * Copyright 2007 Rainer Gerhards and Adiscon GmbH.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * A copy of the GPL can be found in the file "COPYING" in this distribution.
+ */
+
+/* This is the syntax of an expression. I keep it as inline documentation
+ * as this enhances the chance that it is updates should there be a change.
+ *
+ * expr = (simple-string / template-string / function / property) [* expr ]
+ * simple-string = "'" chars "'"
+ * template-string =  '"' template-as--1.19.11-and-below '"'
+ *                   ; string as used in previous $template directive
+ * function = function-name "(" expr ")"
+ * property = [list of property names]
+ */
+
+/* vi:set ai:
+ */