py/runtime: Allow multiple *args in a function call.

This is a partial implementation of PEP 448 to allow unpacking multiple
star args in a function or method call.

This is implemented by changing the emitted bytecodes so that both
positional args and star args are stored as positional args.  A bitmap is
added to indicate if an argument at a given position is a positional
argument or a star arg.

In the generated code, this new bitmap takes the place of the old star arg.
It is stored as a small int, so this means only the first N arguments can
be star args where N is the number of bits in a small int.

The runtime is modified to interpret this new bytecode format while still
trying to perform as few memory reallocations as possible.

Signed-off-by: David Lechner <david@pybricks.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/tests/basics/fun_callstar.py b/tests/basics/fun_callstar.py
index a27a288a3..53d2ece3e 100644
--- a/tests/basics/fun_callstar.py
+++ b/tests/basics/fun_callstar.py
@@ -3,10 +3,16 @@
 def foo(a, b, c):
     print(a, b, c)
 
+foo(*(), 1, 2, 3)
+foo(*(1,), 2, 3)
+foo(*(1, 2), 3)
 foo(*(1, 2, 3))
 foo(1, *(2, 3))
 foo(1, 2, *(3,))
 foo(1, 2, 3, *())
+foo(*(1,), 2, *(3,))
+foo(*(1, 2), *(3,))
+foo(*(1,), *(2, 3))
 
 # Another sequence type
 foo(1, 2, *[100])
@@ -29,10 +35,16 @@ class A:
         print(a, b, c)
 
 a = A()
+a.foo(*(), 1, 2, 3)
+a.foo(*(1,), 2, 3)
+a.foo(*(1, 2), 3)
 a.foo(*(1, 2, 3))
 a.foo(1, *(2, 3))
 a.foo(1, 2, *(3,))
 a.foo(1, 2, 3, *())
+a.foo(*(1,), 2, *(3,))
+a.foo(*(1, 2), *(3,))
+a.foo(*(1,), *(2, 3))
 
 # Another sequence type
 a.foo(1, 2, *[100])