From ba6bc73d20e455ab450f651ca7d02dac7dd0b6c6 Mon Sep 17 00:00:00 2001
From: Andrew Stitcher <astitcher@apache.org>
Date: Thu, 21 Aug 2014 15:00:42 +0000
Subject: QPID-5999: Update selector syntax documentation to reflect the
 implementation

git-svn-id: https://svn.apache.org/repos/asf/qpid/branches/0.30@1619425 13f79535-47bb-0310-9956-ffa450edef68
---
 qpid/cpp/src/qpid/broker/SelectorExpression.cpp | 38 +++++++++++++------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/qpid/cpp/src/qpid/broker/SelectorExpression.cpp b/qpid/cpp/src/qpid/broker/SelectorExpression.cpp
index 8b74ac4667..1e8a90ed4c 100644
--- a/qpid/cpp/src/qpid/broker/SelectorExpression.cpp
+++ b/qpid/cpp/src/qpid/broker/SelectorExpression.cpp
@@ -37,49 +37,51 @@
 
 /*
  * Syntax for JMS style selector expressions (informal):
+ * This is a mixture of regular expression and EBNF formalism
  *
- * Alpha ::= "a".."z" | "A".."Z"
- * Digit ::= "0".."9"
+ * The top level term is SelectExpression
+ *
+ * // Lexical elements
+ *
+ * Alpha ::= [a-zA-Z]
+ * Digit ::= [0-9]
  * IdentifierInitial ::= Alpha | "_" | "$"
  * IdentifierPart ::= IdentifierInitial | Digit | "."
  * Identifier ::= IdentifierInitial IdentifierPart*
  * Constraint : Identifier NOT IN ("NULL", "TRUE", "FALSE", "NOT", "AND", "OR", "BETWEEN", "LIKE", "IN", "IS") // Case insensitive
  *
- * LiteralString ::= ("'" ~[']* "'")+ // Repeats to cope with embedded single quote
+ * LiteralString ::= ("'" [^']* "'")+ // Repeats to cope with embedded single quote
  *
  * LiteralExactNumeric ::= Digit+
- * Exponent ::= ['+'|'-'] LiteralExactNumeric
- * LiteralApproxNumeric ::= ( Digit "." Digit* [ "E" Exponent ] ) |
- *                          ( "." Digit+ [ "E" Exponent ] ) |
+ * Exponent ::= ('+'|'-')? LiteralExactNumeric
+ * LiteralApproxNumeric ::= ( Digit "." Digit* ( "E" Exponent )? ) |
+ *                          ( "." Digit+ ( "E" Exponent )? ) |
  *                          ( Digit+ "E" Exponent )
  * LiteralBool ::= "TRUE" | "FALSE"
  *
  * Literal ::= LiteralBool | LiteralString | LiteralApproxNumeric | LiteralExactNumeric
  *
  * EqOps ::= "=" | "<>"
- *
  * ComparisonOps ::= EqOps | ">" | ">=" | "<" | "<="
+ * AddOps ::= "+" | "-"
+ * MultiplyOps ::= "*" | "/"
  *
- * BoolExpression ::= OrExpression
+ * // Expression Syntax
+ *
+ * SelectExpression ::= OrExpression? // An empty expression is equivalent to "true"
  *
  * OrExpression ::= AndExpression  ( "OR" AndExpression )*
  *
  * AndExpression :: = ComparisonExpression ( "AND" ComparisonExpression )*
  *
- * ComparisonExpression ::= AddExpression "IS" "NULL" |
- *                          AddExpression "IS" "NOT" "NULL" |
- *                          AddExpression "LIKE" LiteralString [ "ESCAPE" LiteralString ] |
- *                          AddExpression "NOT" "LIKE" LiteralString [ "ESCAPE" LiteralString ] |
- *                          AddExpression "BETWEEN" AddExpression "AND" AddExpression |
- *                          AddExpression "NOT" "BETWEEN" AddExpression "AND" AddExpression |
+ * ComparisonExpression ::= AddExpression "IS" "NOT"? "NULL" |
+ *                          AddExpression "NOT"? "LIKE" LiteralString [ "ESCAPE" LiteralString ] |
+ *                          AddExpression "NOT"? "BETWEEN" AddExpression "AND" AddExpression |
+ *                          AddExpression "NOT"? "IN" "(" PrimaryExpression ("," PrimaryExpression)* ")" |
  *                          AddExpression ComparisonOps AddExpression |
  *                          "NOT" ComparisonExpression |
  *                          AddExpression
  *
- * AddOps ::= "+" | "-"
- *
- * MultiplyOps ::= "*" | "-"
- *
  * AddExpression :: = MultiplyExpression (  AddOps MultiplyExpression )*
  *
  * MultiplyExpression :: = UnaryArithExpression ( MultiplyOps UnaryArithExpression )*
-- 
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