py, compiler: Add basic support for A=const(123).

You can now do:

    X = const(123)
    Y = const(456 + X)

and the compiler will replace X and Y with their values.

See discussion in issue #266 and issue #573.

3 files changed, 14 insertions, 1 deletions

diff --git a/tests/micropython/const.py b/tests/micropython/const.py
new file mode 100644
index 000000000..457365c50
--- /dev/null
+++ b/tests/micropython/const.py
@@ -0,0 +1,11 @@
+# test constant optimisation
+
+X = const(123)
+Y = const(X + 456)
+
+print(X, Y + 1)
+
+def f():
+    print(X, Y + 1)
+
+f()
diff --git a/tests/micropython/const.py.exp b/tests/micropython/const.py.exp
new file mode 100644
index 000000000..c447aaf8c
--- /dev/null
+++ b/tests/micropython/const.py.exp
@@ -0,0 +1,2 @@
+123 580
+123 580
diff --git a/tests/run-tests b/tests/run-tests
index 618d11831..9e837c3cb 100755
--- a/tests/run-tests
+++ b/tests/run-tests
@@ -112,7 +112,7 @@ def main():
     if len(args.files) == 0:
         if pyb is None:
             # run PC tests
-            test_dirs = ('basics', 'float', 'import', 'io', 'misc')
+            test_dirs = ('basics', 'micropython', 'float', 'import', 'io', 'misc')
         else:
             # run pyboard tests
             test_dirs = ('basics', 'float', 'pyb', 'pybnative', 'inlineasm')