Use own array implementation in VBS API

[freezy]

This PR adds a new object VbsArray, which should be used in the scripting API, i.e. what the table script and its dependencies deal with when they get an array.

It's a proxy that is iterable and can set and get values, but returns an VbsUndefined object instead of just undefined when an index doesn't exist. VbsUndefined is an empty proxy that either throws an exception when VBS error handling is enabled (On Error Goto 0), or sets the Err object accordingly (if On Error Resume) if it's accessed.

This should mitigate the problem we have in #141. It's actually another fifth solution to the proposed other four.

It might needs to be extended to objects, but I think it's the cleanest solution for now.

TODO

• replace remaining JS arrays in API with VbsArray

[codecov]

Codecov Report

Merging #178 into master will decrease coverage by 0.02%.
The diff coverage is 91.49%.

@@            Coverage Diff             @@
##           master     #178      +/-   ##
==========================================
- Coverage   90.84%   90.83%   -0.01%     
==========================================
  Files         273      275       +2     
  Lines       14342    14359      +17     
  Branches     1675     1678       +3     
==========================================
+ Hits        13028    13042      +14     
- Misses        812      816       +4     
+ Partials      502      501       -1

Impacted Files	Coverage Δ
lib/vpt/collection/collection-api.ts	95.46% <ø> (ø)	⬆️
lib/scripting/transformer/transformer.ts	75.87% <100%> (ø)	⬆️
lib/scripting/objects/vpm-controller.ts	89.39% <100%> (ø)	⬆️
lib/scripting/stdlib/err.ts	93.75% <100%> (+4.87%)	⬆️
lib/scripting/stdlib/index.ts	100% <100%> (ø)	⬆️
lib/scripting/vbs-array.ts	100% <100%> (ø)
lib/scripting/vbs-undefined.ts	100% <100%> (ø)
lib/emu/emulator-state.ts	89.59% <100%> (+0.23%)	⬆️
lib/scripting/post-process/error.ts	100% <100%> (ø)	⬆️
lib/scripting/vbs-helper.ts	81.4% <69.24%> (-5.78%)	⬇️
... and 3 more

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[neophob]

It might needs to be extended to objects, but I think it's the cleanest solution for now.

fully agree yes. So I tested this and my expectation is, that when we use mm-playfield.vpx and see the rom errors (due missing switch settings in the test table) AND press the ESC onscreen button, the rom should be loaded. however I still see

Uncaught TypeError: Cannot set property 'State' of undefined
    at TimerApi.eval (tablescript.js:31)
    at TimerApi.emit (events.js:146)
    at EventProxy.fireDispID (event-proxy.js:50)
    at EventProxy.fireGroupEvent (event-proxy.js:44)
    at PlayerPhysics.updatePhysics (player-physics.js:312)
    at Player.updatePhysics (player.js:89)
    at player.worker.js:88

which points to ` __vbsHelper.getOrCall(__scope.Lights, idx).State = __vbsHelper.getOrCall(ChgLamp, ii, 1);``

shouln't that be solved now? or do I need an updated table with specific error handling enabled?

[freezy]

Your test result is unfortunate ;)

Lemme actually test this :)

[neophob]

stupid users are NEVER guilty ;)

[freezy]

The use case doesn't actually use VbsArray, but a locally declared array. Need to update the VbsHelper.dim() function in order to make that work. Working on it..

[neophob]

AHA, we can another error now:

Uncaught Error: ReferenceError: Cannot set 88 from undefined.
    at VbsArray.get (vbs-array.js:34)
    at VBSHelper.getOrCall (vbs-helper.js:84)
    at TimerApi.eval (tablescript.js:31)
    at TimerApi.emit (events.js:146)
    at EventProxy.fireDispID (event-proxy.js:50)
    at EventProxy.fireGroupEvent (event-proxy.js:44)
    at PlayerPhysics.updatePhysics (player-physics.js:312)
    at Player.updatePhysics (player.js:89)
    at player.worker.js:88

while line 34 looks like return target[key] !== undefined ? target[key] : new VbsUndefined(new VbsError(ReferenceError: Cannot set ${String(key)} from undefined., 9), new VbsError(ReferenceError: Cannot get ${String(key)} from undefined., 9));

[freezy]

Yes, that's expected, because error handling is actually off per default ("off" as is "crash on error"), so now we'll need to implement On Error Resume in order not to crash anymore.

You can temporarily try to set doThrow = false in the Err class.

[neophob]

work great now!

[jsm174]

Thanks for updating the old grammar to support On Error.

In a future PR, I'd like to split Redim into two helpers. One for a normal Redim and one for a Preserve. We could also pass the dimensions in as a variable argument list instead of an array. I think this would make the transpiled code look cleaner.

[freezy]

Thanks for the review guys!