logical operators added

Rev: doc/operators/and:1.3
Rev: doc/operators/logical_and:1.1
Rev: doc/operators/logical_or:1.1
Rev: doc/operators/or:1.3

doc/operators/and

@@ -21,4 +21,4 @@ KEYWORDS
 	operators
 
 SEE ALSO
-	`|, `^
+	`|, `^, &&

doc/operators/logical_and

+NAME
+	&& - logical and
+
+SYNTAX
+	a && b
+
+
+DESCRIPTION
+	This operator does logical 'and' between expressions. It first
+	evaluates a and returns zero if a is zero. Otherwise it returns
+	b. Note that b is not evaluated at all if a returns zero.
+
+
+KEYWORDS
+	operators
+
+SEE ALSO
+	`&, ||

doc/operators/logical_or

+NAME
+	|| - logical or
+
+SYNTAX
+	a || b
+
+
+DESCRIPTION
+	This operator does logical 'or' between expressions. It first
+	evaluates a and returns that if a is non-zero. Otherwise it
+	returns b. Note that b is not evaluated at all if a is non-zero.
+
+KEYWORDS
+	operators
+
+SEE ALSO
+	`|, &&

doc/operators/or

@@ -21,4 +21,4 @@ KEYWORDS
 	operators
 
 SEE ALSO
-	`&, `^
+	`&, `^, ||