Changelog¶

0.5.3 (2023-03-11)¶

Relaxed the lexer to permit floats with an exponent but no decimal point in non-strict mode.
Added sensible error messages when attempting to override a built-in classical function. This is currently disallowed by the structure of the parser.

Added support for CPython 3.7. Qiskit itself has already deprecated support for Python 3.7 and will completely drop it in version 0.25, but for now we can still support it.

Relaxed the lexer to permit single-quoted paths in include statements when not running in strict mode.
Improved error messages caused by failures during the lexing stage.
Several internal refactorings to improve inter-component API boundaries.

Added support for custom_classical functions to load() and loads(). This allows per-run configuration of additional classical functions to make available both during constant folding and defined-gate argument evaluation.
Added the Qiskit-compatibility data QISKIT_CUSTOM_CLASSICAL containing the additions that Qiskit’s built-in parser uses during expression processing.
Relaxed the expression parser to allow trailing commas in classical-function parameter lists. This previously was not allowed because the only defined classical functions by the specification were unary, and parsed rigidly. This is forbidden in strict mode.

Relaxed the parser to allow trailing commas in all list-like elements (of parameters and qubits), as a convenience in the default mode.
Relaxed the parser to allow trailing semicolons after all statements, in particular allowing a semicolon after the body of a gate definition.
Added a strict argument to load() and loads() that causes the parser to enforce the letter of the specification. In particular, the two relaxations above are disabled, and the program must contain and start with a version statement. This mode is more in line with Qiskit’s parser.

Added some missing gates to QISKIT_CUSTOM_INSTRUCTIONS; Qiskit’s legacy importer made rather a lot of changes to the file as presented in the paper!
Fixed incorrect gate creations when a strict subset of the qelib1.inc gates were overridden with custom constructors, or if any user gates were defined after all every gate in that include file was overridden.

Use CU3Gate for cu3 in standard qelib1.inc imports.
Fix the emitted gates for cu3 and id in QISKIT_CUSTOM_INSTRUCTIONS so that the output matches Qiskit’s loads more precisely.

Added support for specifying custom instructions, both builtin and requiring definitions inside the OpenQASM 2 file. This is the custom_instructions parameter to load() and loads().
Added a data element QISKIT_CUSTOM_INSTRUCTIONS that can be passed to custom_instructions to cause qiskit_qasm2 to mostly emulate the behaviour of the Qiskit methods QuantumCircuit.from_qasm_str() and from_qasm_file().

Added support for include statements, with the option to set the include_path in both load() and loads().
Swapped the internal Rust implementation to use dyn BufRead instead of being generic. This reduced compile times and duplication of internal boiler plate in the PyO3 bindings.

Initial release for CPython 3.8 to 3.11, on Linux i686, Linux x86_64, macOS x86_64, Windows x64 and Windows x32.