Programatically triggering a snippet

[s1n7ax]

Requirement:

I think LuaSnip can be used in code refactoring. For instance extract_function could be implemented using LuaSnip. Following would be the steps usually.

• User selects some statements in visual mode
• User fire the keymap for extract_function
• A popup will appear to enter the name of the function
• User types the function and hit enter
• A new function will be created with the selected text as the function body

This is nice but LuaSnip could do it better IMO.

• User selects some statements in visual mode
• User fire the keymap for extract_function_luasnip

vim.keymap.set({ 'x', 'v' }, function ()
  require('luasnip').trigger(sn(1, fmt([[
  function {}(): {} {{
    {}
  }}
  ]], {
    ...
  })))
end, {})

• A function will be created. Neovim will be in Select mode name of the function is selected to enter the name
• LuaSnip ls.jump() can be used to jump to next and prev node

So I'm just wondering if something like this is possible right now or will there be something similar?

[L3MON4D3]

Oh, yeah certainly!! Look for snip_expand in DOC.md, you can expand any snippet, you just need to have the snippet-object (created by s(...)) (there are some other discussions on this, I'm too lazy to look for the exact ones right now, but search should turn them up :) ).
One issue with snip_expand is that it can't handle eg. snippets with regTrig/non-plaintext trigEngine (we don't know whether the text at the expand-position matches the pattern/regex), or more precisely, it can handle them, but it won't set the env-variables.

Regarding your suggestion, that's very possible!
You'd have to set expand_params.env_override.VISUAL to the text selected in visual mode, and then use it inside the snippet (eg. inside a functionNode like f(function(args, parent) return parent.snippet.env.VISUAL end))

Regarding refactoring in general, I think the Treesitter-Postfix-Snippet can come in very useful there because you have a convenient mechanism (treesitter) for capturing specific regions of the syntax-tree. Check the DOC.md-entry I linked, there's a nice example for turning a local function into a variable :D
Right now the treesitter is very coupled to the postfix-part, but it would be certainly possible to make it so that you press a key-combo over some treesitter-node, and it is extracted and its captures passed into a snippet, which could even be expanded elsewhere (though that would require a fair bit of setup :D )