PCRE lookahead

[David263]

I know there is a PCRE syntax for looking ahead but not including a trailing match pattern, but it is impossible to find in the Manual. Searching for "lookahead" returns nothing useful. The PCRE syntax page (https://www.php.net/manual/en/reference.pcre.pattern.syntax.php) doesn't describe the syntax. It lists links for:

Introduction
Delimiters
Meta-characters
Escape sequences
Unicode character properties
Anchors
Dot
Character classes
Alternation
Internal option setting
Subpatterns
Repetition
Back references
Assertions
Once-only subpatterns
Conditional subpatterns
Comments
Recursive patterns
Performance

So you have to know about the particular syntax in order to choose the correct link.

Can this please be fixed? I want to use lookahead.

[damianwadley]

So you were looking for information about lookahead assertions?

[David263]

Yes. I had no idea lookahead was called assertions. Can this please be added to the documentation? Better, please add a more detailed description of each link in the list, with examples. Documentation should be as helpful as possible, not as cryptic and structured as possible.

I'd be willing to expand this page myself, if I had any expectation that my work would be accepted as a replacement for the page. But the Manual has been largely unchanged in recent years, so that expectation is not reasonable.