Invalid regex: lookbehind assertion is not a fixed length

[lildude]

👋 I'm the lead maintainer of the https://github.com/github/linguist library which is used for language detection and providing the syntax highlighting for languages on GitHub.com, and we use this grammar.

Our grammar compiler has found a problem with your grammar which I thought I'd let you know about.

This regex is invalid as the lookbehind assertion is not a fixed length (offset 26):

https://github.com/pvl/abap.tmbundle/blob/a05dfddbd9c605a5f385c099ce7198097d24f3ae/Syntaxes/ABAP.tmLanguage#L56

https://regex101.com/r/TN2tXG/1

This is the error our compiler reported:

Invalid regex in grammar: source.abap (in Syntaxes/ABAP.tmLanguage) contains a malformed regex (regex "(?i)(?<=(?:^|\s|~|->|-|=>))([a-z...": lookbehind assertion is not fixed length (at offset 26))