What are my options to replace Vim cexpr?

[YeungOnion]

It's not reasonable to expect every tool to be integrated into helix, but there are many tools that happen to output a variety of paths with line numbers and (potentially character positions). Vim cexpr allows one to call an expression that gets parsed for files and file positions (parsing configurable).

If I want to get a list (likely a picker) of such information I can navigate through in helix, how would I populate it with locations?