OpenQASM Missing Language Features

[orpuente-MS]

The following features are missing in our OpenQASM implementation, and we plan to implement them in the near future:

• [ ] Index sets arr[{2, 6, 8}].
  • need some clarification from the spec. issue filed
• [ ] Support for OpenQASM 3.2 with nop instructions
• [ ] Extern functions. #2680
• [x] input arrays. [Array type variables are clarified to be supported as inputs.] #2678 (https://openqasm.com/release_notes.html#bug-fixes)
  • [x] Parser and Lowerer
  • [x] Compiler
  • [x] Python
• [x] Array concatenation #2676
• [x] durationof calls. #2611
• [x] Mutable array references as parameters allowed by lowerer and used accordingly. (See below as they aren't supported past the lowerer) #2616
• [x] Alias declarations for qubits. #2665
• [ ] Built-in functions (sin, cos, etc.)
  • [x] Foundation and mod implementation #2508
  • [x] Implementation of builtin functions #2521
  • [ ] pow edge case: pow builtin collides with pow gate modifier.
• [x] box statement. #2571
• [x] sizeof calls. #2586
• [x] Array references (passing arrays as readonly parameters). #2586
• [x] Index into sized types. #2564
• [x] Importing files other than "stdgates.inc". #2512
• [x] Ranges with open start or end: [:1:5], [0:1:]. #2472

These features require work in the Q# compiler and we may implement them at some point, but not in the near future:

• [ ] break keyword.
• [ ] continue keyword.
• [ ] Array references (passing arrays as mutable parameters).
• [ ] alias declarations for bitarrays
• [ ] register concatenation

These features are not planned for full compilation support:

• Hardware qubit ids.
• Duration type value, this includes supplying durations on gate and box instructions.
• Stretch type values.
• Calibration statements.
• Calibration grammar statements.
• Defcal statements.
• Delay statements.