Attempt to perform arithmetic on a nil value (field 'y')

[daelvn]

For some reason, Sirocco has stopped working for me in a script that used to work. Might be due the fact that I'm running it on Alpine on WSL, and I used to run it on Arch, but I don't see the reason why it would affect it.

This is the stacktrace I'm getting:

/home/daelvn/.luaver/lua/5.1.5/bin/lua: .../luarocks/3.2.0_5.1/share/lua/5.1/sirocco/prompt.lua:355: attempt to perform arithmetic on field 'y' (a nil value)
stack traceback:
        [C]: ?
        .../luarocks/3.2.0_5.1/share/lua/5.1/sirocco/prompt.lua:355: in function 'update'
        .../luarocks/3.2.0_5.1/share/lua/5.1/sirocco/prompt.lua:429: in function <.../luarocks/3.2.0_5.1/share/lua/5.1/sirocco/prompt.lua:425>
        (...2 tail call(s)...)
        ...luarocks/rocks-5.1/rockwriter/1.0.2-1/bin/rockwriter:179: in main chunk
        [C]: ?

To reproduce it, I just did

$ luarocks install rockwriter
$ rockwriter example-1.0-1.rockspec

And it should break, although it works fine on my other machine.

It's not urgent, but help would be appreciated. Thanks!

[giann]

What terminal emulator are you running?

[daelvn]

It happens on both Windows Terminal (microsoft/terminal) and the VS Code embedded terminal.

[giann]

What does echo $TERM give you?

[daelvn]

xterm-256color

[giann]

My guess is that your terminal emulator doesn't support the escape code that returns the cursor position. Can you do echo -e "\033[6n" | cat and tell me if you get anything in return. You should get something like ^[[38;1R

[daelvn]

I get ^[[4:1R, yeah.

[giann]

Can I see your script then? this seems to require some debugging.

[daelvn]

Of course.
MoonScript source: https://github.com/daelvn/rockwriter/blob/master/rockwriter.moon
Lua compiled source (may be not readable): https://github.com/daelvn/rockwriter/blob/master/rockwriter.lua

It did use to work with that source, which is what makes it weird. I went to my old laptop running Arch, checked that it still runs, latest version. $TERM is xterm-termite and instead of getting a cursor position like last time, I got 1R in front of the prompt. Like this:

→ ~ 1R

I could try other terminal emulators for Alpine WSL, but I don't know how much success I'd have with them.

[Lessica]

See giann/croissant#9, many terminals won't respond to Prompt.escapeCodes.user7 control question until multiple lines of codes been completely entered, or other user interactions been completely processed.

sirocco/sirocco/prompt.lua

Lines 407 to 411 in b2af2d3

	-- Get current position
	self.output:write(Prompt.escapeCodes.user7)
	self.startingPosition.x,
	self.startingPosition.y = self:getCursor()

So, it's not the right time to fetch the cursor position right after that.

sirocco/sirocco/prompt.lua

Lines 392 to 395 in b2af2d3

	function Prompt:getCursor()
	local y, x = tui.getnext():match("([0-9]*);([0-9]*)")
	return tonumber(x), tonumber(y)
	end

We should check the result of the tui.getnext() call if we got a control response or not. If we got a control response, do the right thing to the terminal layout. Otherwise, just treat these input characters as user's input.