Actors.

[matthewhammer]

Continues #126, implementing Actors.

This test demonstrates how to reproduce the following steps, all of which now work:

1. agent creates a local actor, with a name Counter.
2. agent sends a local actor Counter a message (calling a method)
3. Counter's methods execute with its internal state, and variables.
4. When each method completes, it responds to the agent, which resumes control.
5. agent upgrades actor Counter by re-using the same name later in the script (proof of concept form of upgrade, for unit testing here)
6. the upgrade "works correctly," in the sense that:
   1. the new method definitions run now, and the old ones are replaced.
   2. the store retains its variable's values from before, after the upgrade.

actor Counter = {
  var x = 0;
  public func get() /*: async Nat*/ { x };
  public func inc() { x := x + 1 };
};
assert (Counter.get() == 0);
Counter.inc();
assert (Counter.get() == 1);
actor Counter {
  var x = 0;
  public func get() /*: async Nat*/ { x };
  public func inc() { x := x + 2 };
};
assert (Counter.get() == 1);
Counter.inc();
assert (Counter.get() == 3);
#ok

[github-actions]

Benchmark for c5d627a

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Test	Base	PR	%
Examples/Basic example	686.3±36.72µs	662.5±38.77µs	-3.47%

[github-actions]

Benchmark for 0d901c6

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Test	Base	PR	%
Examples/Basic example	842.1±49.03µs	885.6±47.07µs	+5.17%

[github-actions]

Benchmark for 21ca0b3

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Test	Base	PR	%
Examples/Basic example	677.1±7.57µs	683.5±8.52µs	+0.95%

[github-actions]

Benchmark for 12861fd

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Test	Base	PR	%
Examples/Basic example	683.3±7.52µs	663.4±6.70µs	-2.91%

[matthewhammer]

Create an actor (value) and add it to the VM...

To be useful for Motoko Dev Sever, maybe it should accept a string (read from a file by the caller) and some other stuff, including the canister ID that dfx knows about?

[matthewhammer]

BTW -- the name create is somewhat arbitrary, but has two nice properties now:

• separate verb from alloc, to distinguish it from that case.
• same verb as the IC reference spec, for the act of "creating a canister."

[matthewhammer]

Signal was going to grow to capture errors from I/O.

Except now with the Motoko Dev Server, I am now expecting network I/O to happen outside of the VM, and for this traffic to selectively affect the VM from its public API for Core, which will grow to accommodate the Dev Server.

Accordingly, I am dropping the Signal concept here, and related code.

[github-actions]

Benchmark for ee484b9

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Test	Base	PR	%
Examples/Basic example	656.6±6.78µs	743.7±7.62µs	+13.27%

[matthewhammer]

@rvanasa ActorId could have a variant called DfxCanister or whatever name seems appropriate given what identifier you choose to use.

As you've suggested previously, perhaps it's simplest to just use the "canister alias" dfx concept that we've discussed many times now as the identifier for the DfxCanister case of ActorId? (and eschew having the replica-created canister id as part of that id, e.g., as a pair.)

If so, perhaps we can instead put that extra ID info into the actor as associated data, when it's available.