Changing parenthesis highlighting

[simalaia]

Is there a way to modify the default parenthesis highlighting? I can't find how to do this. I edit a lot of scheme code and needing to have the cursor before a (instead of after) close paren in order to highlight its match is annoying.

[ghost]

If you are willing to build vis from source code, you can apply this commit as a patch.

BTW, there is an open ticket for this behavior - #626 .

[simalaia]

Thanks, I'll look into that when I have a moment. Incidentally I actually think it would be better to expose the functionality to choose how, and which characters to highlight so one could write custom highlighters.

[ghost]

Custom highlighting can already be done, but the problem remains that the built-in match highlighting can't be turned off.

Below's a naive attempt that you can test-drive by putting it in visrc.lua. It's off by a character so you can actually see that it's working.

local opposite = {
    ["["] = "]",
    ["("] = ")",
    ["{"] = "}",
    ["]"] = "[",
    [")"] = "(",
    ["}"] = "{",
}

vis.events.subscribe(vis.events.WIN_HIGHLIGHT, function(win)
    local cur = win.file:content(win.selection.pos, 1)
    local forward = cur:match"[({[]"
    local backward = cur:match"[]})]"
    local start, match
    if forward then
        start = win.selection.pos
        local range = win.file:content(start, win.viewport.finish)
        _, match = range:find("^%b" .. forward .. opposite[forward])
    elseif backward then
        start = win.viewport.start
        local range = win.file:content(start + 1, win.selection.pos - start)
        match = range:find("%b" .. opposite[backward] .. backward .. "$")
        match = match and match + 1
    end
    if match then
        win:style(win.STYLE_CURSOR, start + match, start + match)
    end
end)

[simalaia]

Oh, in that case it may actually work reasonably. May well be simpler to just patch vis to allow builtin highlighting to be turned off. I'll check out your code thank you! :)

[ghost]

May well be simpler to just patch vis to allow builtin highlighting to be turned off. @simalaia

Or, instead, non-Lua builds could keep the current C implementation, and Lua builds could use something like the above code. (Just like all the files under lua/plugins/ contain features only available in Lua builds.) It can be customized without recompiling, and the performance difference with the C implementation won't be a big deal as match highlighting is not called all that often, and only works (and makes sense) on the currently visible portion of the text.