Replacing whitespace with underscores on the fly with an insert node

[dbatten5]

One of my favourite snippets I used with ultisnips was this

snippet f
def $1`!p
t[1] = t[1].replace(' ', '_')
`($2) -> $3:
	$0
endsnippet

It meant that as I typed out the name of a function with spaces, the snippet replaced the spaces with underscores on the fly, meaning I can just freely type out the name of a snake_case function without having to insert underscores. I'm struggling to recreate this with LuaSnip. I figured it might be some combination of function nodes and insert nodes but for the life of me I can't get it to work. Any suggestions?

[L3MON4D3]

Ah, yeah, that's still a WIP 😅
We have dynamicNode, but it can't yet depend on a node inside itself.. but your question sparked some ideas for me, and I'm pretty optimistic that those will bear fruit :)

[dbatten5]

Great to hear! I thought supplying some sort of callback that gets run on the output of a node would do the trick but sure you've got some better ideas

[L3MON4D3]

Oh yeah, you can also do that, but it's not as general as I'd like it to be :D
But it works!:

local events = {[1] = {
	[events.enter] = function(node)
		node.au_id = vim.api.nvim_create_autocmd("TextChangedI", {
			callback = function()
				local t = node:get_text()[1]
				local mod_t = t:gsub(" ", "_")
				node:set_text({mod_t})
			end
		})
	end,
	[events.leave] = function(node)
		vim.api.nvim_del_autocmd(node.au_id)
	end}
}
ls.add_snippets("all", {
	s("def", {
		t"def ", i(1, "function-name")
	}, {
		callbacks = events
	})
}, {key = "def"})

[dbatten5]

Ok nice, looking forward to seeing what you come up with 👍

[L3MON4D3]

Hey, check #1137, it should handle this case just fine :)

[singlexyz]

Like this?

[dbatten5]

Not quite, I'm looking to replace the output of the InputNode in place, not display the transformed output in another node

[singlexyz]

Oh, yes, I've encountered the same issue. #1102
It's possible to pass parameters like "transform" to insertNode.