[Feature]: Change `measure()` to return a future bool

[cqc-alec]

Problem Statement

At runtime, measurements (and any quantum gates preceding them) are only actually performed when the result is needed. The real result of a measurement operation is a future bool, which can later be read to instantiate the value. We want these semantics to be reflected in guppy.

Proposed Solution

We should therefore make the return type of measure() a new type (e.g. MeasureResult, or just Measurement?) with a read() method. We can implement __bool__() on this type as syntactic sugar for read() (so that code like if measure(q) will continue to work as before).

We may want to introduce more general Future[T] types when implementing this. (EDIT: This already exists.)

Component

Guppy Compiler

Effort Estimate

Hard - Significant effort required

Additional Context

No response

[mark-koch]

We may want to introduce more general Future[T] types when implementing this.

This already exists: https://docs.quantinuum.com/guppy/api/generated/guppylang.std.futures.Future.html#guppylang.std.futures.Future

[cqc-alec]

This already exists: https://docs.quantinuum.com/guppy/api/generated/guppylang.std.futures.Future.html#guppylang.std.futures.Future

Ah, I should have checked -- thanks!