Implementation is limited to generating exceptions on `null` or `undefined`. I'm not sure if primitive values don't exist in AVM2 or if this is supposed to box them like ES3, so I have decided to handle neither at this time.
This code is slightly over/under-precise compared to AVM2. This is because we handle precision limiting in binary floats rather than as part of the float printing process. Flash Player may also be rounding differently than us. However, I'm pretty sure ECMA-262 allows us to slightly differ here.
The ECMA-262 documentation is awfully overwrought for something that boils down to "chop off the non-whole part, wrap to 32 bits, then reinterpret as signed". Bitwise operations are *hell* to describe mathematically, and such descriptions are even harder to understand.
For whatever reason, `pushbyte` appears to be processed as a *signed* byte, despite the clear wording of "*byte_value* is an unsigned byte" in avm2overview.pdf. I guess it's supposed to be manually converted and promoted in this manner.
As compiled by Adobe Animate CC 2020, this test appears to only use `iffalse`. However, both `op_is_false` and `op_is_true` coerce in the same manner, so I'm not entirely sure this is a problem for now.
Functions that need to assert Boolness without coercion should either:
1. Ensure their function declaration requires a Boolean. (We don't enforce type errors on ES4 typehints yet, but we should.)
2. Check the value type themselves and raise their own errors if necessary.
As it stands the only users of `as_bool` either needed to check the type themselves or use `coerce_to_bool`. Notably, `setPropertyIsEnumerable` doesn't appear to coerce *or* throw an error: it instead fails silently if you hand it a non-`Boolean` value.
Notably, all of the `Avm1` "run stack frame" functions can no longer take a self parameter as the update context they will be getting also has that same parameter. Ergo, they're associated functions that get the moral equivalent of self from the update context.
This also introduces a new `Activation::from_stub` which creates a stub frame that runs everything on the main movie in layer 0. This significantly reduces boilerplate code elsewhere in the project.
This also removes the function parameter on `sort_compare_numeric`. As it was only being used for string comparisons, and it was causing unfixable lifetime issues, I have instead had it take the case-sensitivity flag and call the two functions it would have been passed anyway. This fixes the lifetime issue.
The process of constructing an `Activation` now involves calling `UpdateContext.reborrow`, which "sheds" a lifetime by copying all of the borrows into a new "owned" context with that lifetime.
Likewise, to call out to functions that don't need an `Activation`, just borrow the context out of the current activation. You can also construct child-frame activations by reborrowing the parent activation's context.
There is a race condition inadvertently caused by allowing movies to be fetched in slot 0: it is possible for the player to be caught mid-load without a root movie. A lot of code assumes level 0 always exists (e.g. `levels.get(0).unwrap()`), while our initialization methods assumed no Player methods would be called until the root movie is installed. This is an unreasonable assumption, as among other things users can trigger the race condition by just playing the movie too quickly.
This allows us to remove the conditionals on implementations of `from_path` that need to call this function, as the function is now always guaranteed to be there, even if it's just a no-op/`Err` generator.
During the small period of time when a player is created but has no root movie, a temporary empty movie is installed with an assumed stage size and framerate of 550x400@12fps. This is Flash default for new projects, so it seemed appropriate. User ActionScript cannot see these values, and I'm not even sure JavaScript can, either.
Calling loadMovieNum with a variable parameter compiles into a
GetURL2 call with a `_level` window target parameter. Previously
this triggered Ruffle to try to navigate to the SWF. Now it
properly loads the SWF inside the current movie.