Initial pull requst for review for adding a new QuantumCircuit constructor

[BramDo]

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Summary

First commit on #8709 This is a first commit for adding a new QuantumCircuit constructor QuantumCircuit.from_instructions. It uses a rough interface, so it is missing bookkeeping and set tracking. The code for testing the method from_instruction can be found in circuit_draw.py.

Details and comments

Method for the constructor

@classmethod
    def from_instructions(
        cls, instructions: Iterable[CircuitInstruction], *, name=None, metadata=None, global_phase=0
    ):
        """Return a circuit from instructions

        Returns:
            QuantumCircuit: a circuit from instructions
        """

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[1ucian0]

Hi @BramDo, welcome to the community! Take a look to the contributor guidelines if you didn't already. Also, considering starting with a good first issue as help wanted issues tend to assume your are familiar with the Qiskit internals and code-style.

You can also pass by #qiskit-pr-help on Slack if you need extra guidance.

[BramDo]

I dont think this works with classical bits (let allow with conditions). Testing is always needed, but even more for this kind of code with so many corner cases.

The comment #8709 (comment) provides really good initial guidance on the direction.

Thank you for the review and the helpful insights. I will investigate how to implement this with classical bits according to the mentioned guidance. Good point about the conditions, that part is still open. I will go to slack for further questions.

[BramDo]

This is still work in progress.

[kevinsung]

Bram has dropped out of the QAMP project this PR was for. I will take over this issue. Please close this PR and I'll open a new one.