vim custom syntax highlighting

Question

I'm wanting to create custom syntax highlighting in vim for a task-list.

Task items begin with a hyphen. Two types of task items are relevant: (a) items without an '@done' tag. (b) items with an @done tag. (a) and (b) need to be highlighted differently.

I'm using taskpaper, which works fine, but the issue is, I'm trying to make this to work for task items that span multiple lines. For example:

- Regular item (works)
- Completed item @done (works)
- Multi-line item. This item continues on to 
  the line below. (doesn't work)
- Multi-line completed item. This item continues
  on to the line below. (doesn't work). @done

The highlighting file at taskpaper works for the first two, but not for the second two. As a workaround hack, I tried this for the last case above:

syn region multLineDoneItem start="{" end="}" fold
HiLink multLineDoneItem NonText

But now, I'm forced to mark multi-line done items with braces like so:

- {Multi-line completed item. This item continues
  on to the line below. (workaround works).}

I've already searched stackexchange and elsewhere. I would appreciate any help! :)

Answer 1

You could try using the \ze regex atom in the end part of your syntax region. This would allow you to match everything up to but not including the next task. I haven't looked at how you do matching but something like this might work.

syn region muiltLineItem     start="^-" end="\(\s*\n)\+\ze^-" fold    
syn region multiLineDoneItem start="^-" end="@done\s*\n\(\s*\n\)*\ze^-" fold
HiLink multiLineItem Normal
HiLink multiLineDoneItem NonText

I haven't tested this at all but I think it, or something like it, should work. If you wish to take indentation into account the \z regex atom will allow you to keep matching lines with the same indent.

UPDATE:

Try this:

syn match multilineItem "^-\_.\{-}\ze\(\n-\|\%$\)" fold
syn match multilineDoneItem "^-\(\%(\_^-\)\@!\_.\)\{-}@done\s*\n\ze" fold
command -nargs=+ HiLink highlight default link <args>
HiLink multilineItem Normal
HiLink multilineDoneItem NonText
delcommand HiLink

Oh, also this should work for all four cases and not just the multi-line items.