convert ExpressionConvertible to duration

oqpy/timing.py

@@ -72,19 +72,19 @@ def convert_float_to_duration(time: AstConvertible, require_nonnegative: bool =
         if require_nonnegative and time < 0:
             raise ValueError(f"Expected a non-negative duration, but got {time}")
         return OQDurationLiteral(time)
+    if hasattr(time, "_to_oqpy_expression"):
+        time = cast(ExpressionConvertible, time)
+        time = time._to_oqpy_expression()
+    if hasattr(time, "_to_cached_oqpy_expression"):
+        time = cast(CachedExpressionConvertible, time)
+        time = time._to_cached_oqpy_expression()
     if isinstance(time, OQPyExpression):
         if isinstance(time.type, (ast.UintType, ast.IntType, ast.FloatType)):
             time = time * OQDurationLiteral(1)
         elif not isinstance(time.type, ast.DurationType):
             raise TypeError(f"Cannot convert expression with type {time.type} to duration")
     if hasattr(time, "to_ast"):
         return time  # type: ignore[return-value]
-    if hasattr(time, "_to_oqpy_expression"):
-        time = cast(ExpressionConvertible, time)
-        return time._to_oqpy_expression()
-    if hasattr(time, "_to_cached_oqpy_expression"):
-        time = cast(CachedExpressionConvertible, time)
-        return time._to_cached_oqpy_expression()
     raise TypeError(
         f"Expected either float, int, HasToAst or ExpressionConverible: Got {type(time)}"
     )

tests/test_directives.py

@@ -1572,19 +1572,29 @@ class A:
 
         def _to_oqpy_expression(self):
             return DurationVar(1e-7, self.name)
+
+    @dataclass
+    class B:
+        name: str
+
+        def _to_oqpy_expression(self):
+            return FloatVar(1e-7, self.name)
 
     frame = FrameVar(name="f1")
     prog = Program()
     prog.set(A("a1"), 2)
     prog.delay(A("a2"), frame)
+    prog.delay(B("b1"), frame)
     expected = textwrap.dedent(
         """
         OPENQASM 3.0;
         duration a1 = 100.0ns;
         duration a2 = 100.0ns;
         frame f1;
+        float[64] b1 = 1e-07;
         a1 = 2;
         delay[a2] f1;
+        delay[b1 * 1s] f1;
         """
     ).strip()
     assert prog.to_qasm() == expected