string(SPLIT should be a thing.
string(SPLIT is something I keep finding myself needing. There are hacks around it, using separate_arguments() (which splits on spaces) after first replacing whitespace using some obscure delimiter, then putting the spaces back in after separate_arguments() does it's thing.
But a string(SPLIT mode would be super handy. Along with string(REGEX SPLIT, it would split strings into cmake lists based on a delimiter. An option to automatically trim etc would be handy. But basically just a really simple, common, standard string(SPLIT functionality seems like a bug when it's missing imo.
I realize that string(REGEX MATCHALL can be used to achieve this as well, but it seems like a SPLIT option would be easier to reach for as a coder, more clear in the code, and less likely to get wrong.