Broadcasting and slicing updates #2326

orpuente-MS · 2025-04-22T21:51:33Z

This PR completes some postponed items from #2149:

Gate call broadcasting.
Multidimensional array indexing.
Array slicing.
Fixes issue with assign ops being compiled incorrectly.

idavis · 2025-04-22T23:00:25Z

compiler/qsc_qasm/src/compiler.rs

+        for index in &index_expr.indices {
+            let index = self.compile_index(index);
+            let span = Span {
+                lo: index_expr.span.lo,


This lo span doesn't feel correct

There is no right answer here since the source syntax is different from Q#'s syntax.

The idea is that this source code

a[1, 2, 3, 4]

will get compiled to

a[1][2][3][4]

The span in your comment is the span of the expression being indexed. For example, if we are currently building a[1][2][3], the expression being indexed is a[1][2]. But in the source code this corresponds to a[1, 2, and that's what I'm setting the span to, which doesn't feel as intuitive as in Q#, but it's a best effort solution. Let me know if you can think of something better.

compiler/qsc_qasm/src/parser/stmt.rs

compiler/qsc_qasm/src/semantic/lowerer.rs

orpuente-MS added 7 commits April 21, 2025 16:44

broadcasting

c190235

fix parsing and lowering of indexed idents

12f8fae

update indexed_ident tests

8a04ec0

broadcasting edge case

14293f5

update unit tests

a80a5a6

remove empty lines

4a8f3ff

unignore slicing tests

c2596b4

idavis changed the title ~~Qasm parser follow up~~ Broadcasting and slicing updates Apr 22, 2025

orpuente-MS added 2 commits April 22, 2025 15:21

box IdentOrIndexedIdent

d3ca004

allow broadcast with mixed registers and qubits

f549de4