diff --git a/syntax.htm b/syntax.htm index 10e01b8d..f6b18f8f 100644 --- a/syntax.htm +++ b/syntax.htm @@ -157,9 +157,18 @@ but don't want the parenthesis to spit out another marked sub-expression, in this case a non-marking parenthesis (?:expression) can be used. For example the following expression creates no sub-expressions:

-

"(?:abc)*"
- 
- 

+

"(?:abc)*"

+ +

Forward Lookahead Asserts 

+ +

There are two forms of these; one for positive forward +lookahead asserts, and one for negative lookahead asserts:

+ +

"(?=abc)" matches zero characters only if they are +followed by the expression "abc".

+ +

"(?!abc)" matches zero characters only if they are +not followed by the expression "abc".

Alternatives