Auto-complete for function macros

Function macros are some of the most powerful tools in vanilla minecraft. They alone make custom commands a possibility, yet they're very convoluted to use, especially if you have no prior knowledge on what variables you need to include. What I am asking for is auto-complete for macro variables, just like how there's auto-complete for function names with empty values.

For example, a function such as this;

$say $(word1)
$scoreboard players add @s score $(amount)
$give @s $(item)

Would look like this when typed out:

/function mypack:dothings {word1:"",amount:"",item:""} <- This is the part that gets filled in