For each index & value loop.

[Moderocky]

Description

Having talked with Ayham about my concerns, I've opened this as an alternative proposal to Ayham's loop PR #6053.

This will be in draft until we reach a consensus about which approach to adopt.

Ayham's syntax was:

loop %objects% with index as %-~object%
loop %objects% [with index] as %-~object%( and|,) [with value] %-~object%
loop %objects% [[with value] as %-~object%]

I'm not very happy about changing or adding to the existing loop ... section syntax, because it's such an old and established thing, and I worried that the syntax was becoming a bit long and difficult to interpret.
I also thought this feature might be a good opportunity to mimic for-each loops from other languages like Java and Python.

My alternative for-each is specifically designed for dealing with key<->value maps,
by storing the index and value in reference variables.

It also extends the existing SecLoop so all loop behaviour is available as normal.

The syntax is (note ~object specifically accepts a variable):

for [each] [value] %~object% in %objects%
for [each] (key|index) %~object% in %objects%
for [each] [key|index] %~object% (=|and) [value] %~object% in %objects%

Note: while I wanted to do for A, B in ... (like Python) I was concerned that Skript might mistake this for for <list of A, B> in ... rather than for <A>, <B> in ....

set {_list::*} to 1, 5, and 10

# loop-by-value like a regular loop
for each {_value} in {_list::*}:
    broadcast {_value}

for value {_value} in {_list::*}:
    broadcast {_value}

# loop-by-index
for index {_index} in {_list::*}:
    broadcast {_index}

# loop by index = value
for index {_index} and value {_value} in {_list::*}:
    broadcast "%{_index}% = %{_value}%"

for {_index} and {_value} in {_list::*}:
    broadcast "%{_index}% = %{_value}%"

for {_index} = {_value} in {_list::*}:
    broadcast "%{_index}% = %{_value}%"

Note: this is registered as an experimental feature, toggled with using for each loops.

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Target Minecraft Versions: any
Requirements: #6551, #6552
Related Issues: #6052, #6053

[Pikachu920]

I'm still not sure about this feature. I think the existing system works well, and I think there's a benefit in just having a single simple way to loop things.

[Moderocky]

I'm still not sure about this feature. I think the existing system works well, and I think there's a benefit in just having a single simple way to loop things.

I'm happy with that too, but if people decide we need something I am in favour of this being it.

[sovdeeth]

Pretty much every loop I've written recently has looked like this, when more than one nested loop is involved.

loop 10 times:
    set {_counter} to loop-value
    loop {_something::*}:
        set {_value} to loop-value-2

It's just so much easier to keep track of what's what, helps avoid off-by-one errors in the loop-value-x, and being able to have descriptive names makes the code way more legible. That said, this code is perfectly fine to keep, but I feel like this addition would be valuable in that it would remove the dead weight of those set lines.

[Moderocky]

helps avoid off-by-one errors in the loop-value-x

I have a vague memory that there are some cases where you can't use the loop-<something>-x because it isn't available within some kinds of subsections (or something like that) and you have to copy it to a variable too.

[sovdeeth]

helps avoid off-by-one errors in the loop-value-x

I have a vague memory that there are some cases where you can't use the loop-<something>-x because it isn't available within some kinds of subsections (or something like that) and you have to copy it to a variable too.

Yes, any section that resets the events (EffSecSpawn, for example) means you have to put the loop-value into a var in order to access it in the section, since when it runs isn't guaranteed.