add declaration snippet (c)

lua/snippets/c.lua

@@ -1,23 +1,43 @@
 require('core.snippets.shorthands')
 
-return {
-  -- method snippet
-  s("main", {
-    c(1, {
-      t(""),
-      t("static "),
-    }),
-    t("int main("),
-    c(2, {
-      t("int argc, char *argv[]"),
-      i(1, "void"),
-    }),
-    t(")"),
-    t({ " {", "\t" }),
-    i(0),
-    t({ "", "}" }),
-  }),
+--- create a decleration of a function from it's definition using treesitter
+---@param func string
+---@return string|nil
+local function c_func(func)
+  local tree = vim.treesitter.get_parser():parse()[1]:root()
 
+  local q = vim.treesitter.query.parse("c", [[
+  (function_definition
+    declarator: (function_declarator
+      (identifier) @function_name
+    )
+  )
+  ]])
+  local matches = q:iter_matches(tree, 0)
+
+  for _, match in matches do
+    for _, node in pairs(match) do
+      if vim.treesitter.get_node_text(node, 0) == func then
+        while node:type() ~= "function_definition" do
+          node = node:parent()
+        end
+        local def = ""
+        for i = 0, node:child_count() - 2 do
+          def = def..vim.treesitter.get_node_text(node:child(i), 0)
+          if i < node:child_count() - 2 then
+            def = def.." "
+          end
+        end
+        -- Print the function name using node text
+        return def:gsub("\n", "")
+      end
+    end
+  end
+
+  return nil
+end
+
+return {
   -- function snippet
   s({ trig = [[fn\|main]], trigEngine = "vim" }, {
     d(1, function(_, snip)
@@ -57,5 +77,19 @@ return {
     i(0),
     t({ "", "}" })
   }),
+
+  -- create decleration based on existing c function
+  postfix(".d", {
+    f(function(_, parent)
+      local r = c_func(parent.snippet.env.POSTFIX_MATCH)
+      if not r then
+        return parent.snippet.env.POSTFIX_MATCH
+      end
+      local bidx, aidx = r:find(parent.snippet.env.POSTFIX_MATCH)
+
+      return r:sub(1, bidx - 1)..
+        parent.snippet.env.POSTFIX_MATCH..
+        r:sub(aidx + 1)..";"
+    end, {})
   })
 }