Add .each and .each_with_index to various macro types

[Blacksmoke16]

• Extracted from 131fcba and 63e37f0

Since #9091 is in a holding pattern; I figured it would good to at least add some of macro methods that it was adding. I was actually able to reimplement my DI refactor (minus the compiler passes) with just this PR, and a lot of duplication. This will satisfy my needs until #9091 can go through a proper design phase.

[RX14]

Isn't this redundant with macro {% for?

Though I'm happy to add this, I'd rather have one or the other eventually, not both

[Blacksmoke16]

Isn't this redundant with macro {% for?

No because:

{% begin %}
  {% hash = {"one" => {data: [[2, 2, 2], 2, 3]}, "two" => {data: [4, 5, 6]}} %}

  {% for key, value in hash %}
    {% arguments = value[:data].map do |v|
         if v.is_a? ArrayLiteral
           c = 0
           # Can't iterate over the inner array since you cant nest macro expressions
           c
         else
           v + 1
         end
       end %}
    {{pp arguments}}
  {% end %}
{% end %}

This enables that. I'm sure you could rewrite this to use {% for .. but It would be quite an unwieldy beast.

EDIT: It's more needed for iterating over HashLiterals, since you can't use .map as a workaround like you can with array or tuples.

[Blacksmoke16]

Can I get another review on this?

[Blacksmoke16]

Anything left to do? Would be nice to get this into the nightly build.

[straight-shoota]

Thanks @Blacksmoke16