Cannot make insert node 0 "inside" the snippet content

[fidelski]

I started to migrate from Ultisnips to LuaSnip - thanks a lot for this awesome, incredibly well thought out and amazingly powerful snippet engine that even supports multiple source formats (snipmate, vscode, Lua ❤️ ...). Converting the snipmate snippets was extremely easy I only struggle with one last bit that puzzles me and is most probably due to a lack of understanding on my side. Short: I wanted to create a snippet for my c/c++ header include guards so I created a c/incguard.lua snippet:

local function get_guard_name ()
    local name = vim.fn.expand ('%:.'):lower ()
    for _, item in ipairs ({'src', 'sources', 'build'}) do
        name = name:gsub (item .. '/', '')
    end
    return name:gsub ('[/\\.-]', '_'):upper() .. '_INCLUDED'
end

local function guard_node ()
    return sn (nil, fmt ([[
    #ifndef {}
    #define {}
    {}

    #endif // NOT {}

    ]], {i (1, get_guard_name ()), rep (1), i (2), rep (1)}))
end

return {s ({trig = 'incguard', desc = 'Insert include guard'}, {d (1, guard_node)})}

This works nicely but I need to use i(2) in the snippet in order to be able to jump into the second insert. I initially wanted to put i(0) in there, since I wanted to «end» the snippet there and not «after» the entire snippet content. If I do so I still end up after the snippet instead of the second insert node. What am I doing wrong here?

[fidelski]

I obviously overlooked the following statement in the docs about node references:

number: the jump-index of the node. This will be resolved relative to the parent of the node this is passed to. (So, only nodes with the same parent can be referenced. This is very easy to grasp, but also limiting)

And since the dynamic node is not the root it cannot access its index. The following works as expected:

local function guard_name_node () return sn (nil, {i (1, get_guard_name ())}) end

return {
    s ({trig = 'incguard', desc = 'Insert include guard'}, fmt ([[
    #ifndef {}
    #define {}
    {}

    #endif // NOT {}

]], {d (1, guard_name_node), rep (1), i (0), rep (1)}))
}