Change list evaluation to collecting all pushed items on a new stack

[RubenVerg]

No description provided.

[lyxal]

Make sure to add tests in InterpreterTests

[lyxal]

I'll wait for user to have a check before merging

[ysthakur]

Maybe we could add a stack parameter to Context#copy to avoid having to clear later?

[ysthakur]

Can list elements still access what was on the stack before the list literal started executing? If not, maybe we could do something closer to the old code, except record the length of the stack before each element starts executing so we can pop the appropriate number of elements? But that would get messed up if you popped something that was on the stack already and pushed something else (e.g. 3 #[ 2 + #]).

Maybe if we could make a child context that only uses the parent context's when its own stack runs out of elements? But that's not how child contexts work right now

[RubenVerg]

@ysthakur lxyal and I agreed that allowing access to the outer stack leads to code that's hard to decide what should happen such as your example, so we opted for using a separate, empty-by-default stack. Maybe an alternative could be a parent stack that's read-only, so for example 3 #[1 + #] would use the 3 but not pop it from the stack. That however seems much harder to implement, and it doesn't seem that useful. If you want to access things from the outer stack, use the primitives that build lists

[ysthakur]

Ah ok, makes sense then. LGTM