Can vim highlight nestable regions?

Question

Is vim's syntax highlighting limited by regexes or can you, for example, highlight [ words_and_maybe_keywords... [ words_and_maybe_keywords... ] words_and_maybe_keywords... ] all the same (e.g., green) all based on this region being demarcated by some outermost [/] pair?

IOW, can it handle regexes + depth?

If this is supported, how can I highlight such a nestable region?

Answer 1

I've tried looking at a syntax file which might be using the feature: pascal.vim, because pascal, as I've learned, has nested comment sections. Unfortunately, the highlighting for the comment section is wrong when there's nesting in the comments.

Example hello_world.pas:

program HelloWorld(output);
begin
    Write('Hello, World!')
    {No ";" is required after the last statement of a block -
    { nested comment }
        adding one adds a "null statement" to the program, which is ignored by the compiler.}
end.

This compiles and runs, but the comment section with nesting is highlighted wrong, even here on the StackOverflow.

I found the relevant line in the syntax file:

syn region pascalComment    start="(\*\|{"  end="\*)\|}" contains=pascalTodo,pascalSpaceError

and just naively added ,pascalComment to the contains attribute` and it did make vim highlight the comment region correctly.