The best completion are those that let you avoiding mistyping variable names or figure out some dependency (automatically import the modules, restrict to the current scope/structure). Those has been solved for decades now. And you can get a dumb ones by doing a list of all symbols in the project directory, removing common keyword and punctuation, and do some kind of matching for filtering. The other side of the spectrum is the kind of code indexing IDEA and LSP server do.
Then you got into code boilerplate, and if you find yourself doing this a lot, that's a signal to start refactoring, add some snippets to your editor (error handling in go), write some code generators, or lament the fact that your language can't do metaprogramming.
> but I'm really not lamenting the fact that I don't have to be looking up parameters or exact function names any more.
That's a reckless attitude to have, especially if the function have drastic behavior switch like mutating argument or returning a fresh copy. All you do is assume that it behaves in certain way while the docs you haven't read will have the related warning label.
Then you got into code boilerplate, and if you find yourself doing this a lot, that's a signal to start refactoring, add some snippets to your editor (error handling in go), write some code generators, or lament the fact that your language can't do metaprogramming.
> but I'm really not lamenting the fact that I don't have to be looking up parameters or exact function names any more.
That's a reckless attitude to have, especially if the function have drastic behavior switch like mutating argument or returning a fresh copy. All you do is assume that it behaves in certain way while the docs you haven't read will have the related warning label.