py/parse: Treat constants that start with underscore as private.

Assignments of the form "_id = const(value)" are treated as private
(following a similar CPython convention) and code is no longer emitted
for the assignment to a global variable.

See issue #2111.

2 files changed, 15 insertions, 0 deletions

diff --git a/tests/micropython/const.py b/tests/micropython/const.py
index 457365c50..09717fd14 100644
--- a/tests/micropython/const.py
+++ b/tests/micropython/const.py
@@ -9,3 +9,15 @@ def f():
     print(X, Y + 1)
 
 f()
+
+_X = const(12)
+_Y = const(_X + 34)
+
+print(_X, _Y)
+
+class A:
+    Z = const(1)
+    _Z = const(2)
+    print(Z, _Z)
+
+print(hasattr(A, 'Z'), hasattr(A, '_Z'))
diff --git a/tests/micropython/const.py.exp b/tests/micropython/const.py.exp
index c447aaf8c..ece6a5cb2 100644
--- a/tests/micropython/const.py.exp
+++ b/tests/micropython/const.py.exp
@@ -1,2 +1,5 @@
 123 580
 123 580
+12 46
+1 2
+True False