seq-map on vector that returns a vector?

[Silex]

Hello,

Why do some function respect the sequence type and some other convert to list?

Is it because of implementation issues or is it because it's desired? Wouldn't eventually all methods return the same type?

For example, the following surprised me:

(seq-map '1+ [1 2 3 4]) ;; => '(2 3 4 5)

Having to (apply '#vector ...) all the time annoys me 😆

[NicolasPetton]

Philippe Vaucher <[email protected]> writes:

Hello,

Hi Phillipe,

For example, the following surprised me: ``` emacs (-map '1+ [1 2 3 4]) ;; => '(2 3 4 5) ```

That seems to be -map for dash.el, but indeed seq.el behaves the same way here. I agree that it can be surprising.

[Silex]

I see that you reply by email and thus miss the edits I did (I edited it to be seq-map).

Anyway, what about the questions? Is it because of implementation issues or is it because it's desired? Shouldn't theoretically all methods return the same type as passed?

[NicolasPetton]

Philippe Vaucher <[email protected]> writes:

I see that you reply by email and thus miss the edits I did (I edited it to be `seq-map`).

Ah, ok :)

Anyway, what about the questions? Is it because of implementation issues or is it because it's desired? Shouldn't theoretically all methods return the same type as passed?

When implementing seq-map, I didn't mind returning a list from another seq type, as the implementation as much easier that way. I do understand that it can be surprising though, so I would agree to change that behavior.

[Silex]

Okay, continuing in #11