Regex grouping template with first, middle and end group-CodePudding

I would like to create a regex with the following requirements.

First (single) char unicode letter with including and excluding option (GROUP1)
Second (and more) char optional list with including and excluding option (GROUP2)
End (single) char unicode letter with including and excluding option (GROUP3)

It should not be permissible for one and the same not letter to appear twice in a row, what i ve is this now

^(?!.{32})(?:[\p{L}.]*?)(?:[ ,'-][\p{L}.] )*?$

CodePudding user response：

I'm unsure what you mean with your three different groupings, but by your sample data it looks like you could try:

^(?!.{136})\p{L} \.?(?:[ ,'-]?\p{L} \.?)*$

See an online demo

^ - Start-line anchor;
(?!.{136}) - Negative lookahead to avoid a line to have 136 (or more) characters other than newline;
\p{L} \.? - Any 1 (Greedy) letter from any language and an optional literal dot;
(?:[ ,'-]?\p{L} \.?)* - A non-capture group (0 times) to optionally match any character from the give class and any 1 letter from any language followed by another optional dot;
$ - End-line anchor.