Add Dictionary.merge()

[KoBeWi]

Implements godotengine/godot-proposals#3739, based on my comment here: godotengine/godot-proposals#1756 (comment)
with 2 differences:

• it modifies the Dictionary instead of creating a new one
• I added overwrite parameter

[YuriSizov]

You seem to have a tiny style issue 👀

[akien-mga]

Thanks!

[bend-n]

In the array edition, it's append_array. Why is it merge in this instance? Wouldn't it be better to be consistent with naming?

[akien-mga]

@bend-n "append" means "add at the end", so it makes sense for an ordered list like an array. Dictionaries aren't ordered and so the new (key, value) sets are not added at the end, but merged with the existing keys. So if this were a real-life language dictionary, "append" would be adding an appendix of new words, while "merge" creates a new edition of the dictionary with the words interspersed.

[Mickeon]

Can this be backported to 3.x?

[bend-n]

@bend-n "append" means "add at the end", so it makes sense for an ordered list like an array. Dictionaries aren't ordered and so the new (key, > value) sets are not added at the end, but merged with the existing keys. So if this were a real-life language dictionary, "append" would be adding an appendix of new words, while "merge" creates a new edition of the dictionary with the words interspersed.

Thanks, I see. Its more of a "makes sense" thing than a consistency thing.

[akien-mga]

Cherry-picked for 3.5.

Note that I didn't bother adding it to the GDNative header - if someone wants to, feel free.