tags: look for args in the suffix only

[Rainrider]

This fixes '[ ($>test:tag<$)]' resulting in (42 instead of (42) in a backwards compatible way.

Here a simple use case for testing in case I missed something:

local function getBracketData(tag)
    -- full tag syntax: '[prefix$>tag-name<$suffix(a,r,g,s)]'
    local prefixEnd, prefixOffset = tag:match('()$>'), 1
    if(not prefixEnd) then
        prefixEnd = 1
    else
        prefixEnd = prefixEnd - 1
        prefixOffset = 3
    end

    local suffixEnd = (tag:match('()%(', prefixOffset + 1) or -1) - 1
    local suffixStart, suffixOffset = tag:match('<$()', prefixEnd), 1
    if(not suffixStart) then
        suffixStart = suffixEnd + 1
    else
        suffixOffset = 3
    end

    return tag:sub(prefixEnd + prefixOffset, suffixStart - suffixOffset),
        prefixEnd,
        suffixStart,
        suffixEnd,
        tag:match('%((.-)%)', suffixOffset + 1)
end

local function getAffixes(tag, prefixEnd, suffixStart, suffixEnd)
    local prefix = tag:sub(2, prefixEnd)
    local suffix = tag:sub(suffixStart, suffixEnd)

    return prefix ~= '' and prefix or nil,
        suffix ~= '' and suffix or nil
end

local tags = {
    '[test:tag]',
    '[prefix$>test:tag]',
    '[test:tag<$suffix]',
    '[prefix$>test:tag<$suffix]',
    '[test:tag(args)]',
    '[prefix$>test:tag(args)]',
    '[test:tag<$suffix(args)]',
    '[prefix$>test:tag<$suffix(args)]',
    '[ ($>test:tag<$)]',
    '[ ($>test:tag<$)(args)]',
}

for _, tag in next, tags do
    local name, pe, ss, se, args = getBracketData(tag)
    local p, s = getAffixes(tag, pe, ss, se)

    print(tag, name, p, s, args)
end

This breaks with something like '[ ($>test:tag<$(suffix)(args)]' which is IMO a limitation of the current tag syntax. We should have placed the argument list before the suffix delimiter. The following solution would fix this but in a backwards incompatible way:

local function getBracketData(tag)
    -- syntax: '[prefix$>tag-name(a,r,g,s)<$suffix]'
    local prefixEnd = tag:match('()$>') or 1
    local prefixOffset = prefixEnd == 1 and 1 or 2
    local suffixStart = tag:match('<$()') or -1
    local suffixOffset = suffixStart == -1 and -1 or -3
    local tagName = tag:sub(prefixEnd + prefixOffset, suffixStart + suffixOffset)
    local args = tagName:match('%((.-)%)')
    if (args) then
        tagName = tagName:gsub(args, ''):sub(1, -3)
    end

    if (prefixEnd ~= 1) then
        prefixEnd = prefixEnd - 1
    end

    return tagName, prefixEnd, suffixStart, -2, args
end

[ls-]

@Rainrider could you add the test stuff to the code? Just leave it there commented out, it could be pretty handy in the future. Or alternatively, add a comment with a link to this PR or Gist with the test code. Also, did you test the strip func? As for changing the tag syntax, I'm open to it, just make a new PR and label it as next major.

[Rainrider]

@ls- Nope, missed the strip ofc. Will take a look later, the weather here is way too fantastic to miss out. As for the test "case" I'd rather squash merge, which will add a ref to the PR, and I'll mention it in the commit message, if you are fine with this.

[Rainrider]

strip should be fine, there is nothing special there and the fix doesn't change the tag syntax, so if it is broken, it was that way before as well.

[ls-]

@Rainrider it'd be nice to have a reminder in the comments that there's a test case people, us included, can take a look at. Like, in 6-12mo I won't even remember what's going on in there 😁 And have fun 🏖

[ls-]

And yeah, strip works just fine, dw

[test:tag]                       ==> [test:tag] 0
[prefix$>test:tag]               ==> [test:tag] 0
[test:tag<$suffix]               ==> [test:tag] 1
[prefix$>test:tag<$suffix]       ==> [test:tag] 1
[test:tag(args)]                 ==> [test:tag] 0
[prefix$>test:tag(args)]         ==> [test:tag] 0
[test:tag<$suffix(args)]         ==> [test:tag] 1
[prefix$>test:tag<$suffix(args)] ==> [test:tag] 1
[ ($>test:tag<$)]                ==> [test:tag] 1
[ ($>test:tag<$)(args)]          ==> [test:tag] 1