Lookarounds provide you with an easy way of applying conditions to your expressions. Think if them as simple if-statements: If that happened, match this.

if followed by / if not followed by

if [not] followed by

Sometimes, you may only want to match a certain condition if it is directly followed by a given other condition.

This can be done using lookahead. In SRL, a lookahead can be positive (if followed by) or negative (if not followed by). The example below will only capture the number, if it's no more followed by any other number.

capture (digit) if not followed by (anything once or more, digit)

if already had / if not already had

if [not] already had

Just like a lookahead, the lookbehind, which can be positive and negative as well, matches the characters exactly before that condition.

For example, you may only want to match bar if it's directly following foo:

capture "bar" if already had "foo"