restructure + syntactic sugar implementation

tests/test_builtin.py

@@ -0,0 +1,85 @@
+from simpleparser import parse
+from interpreter import Interpreter
+
+
+def test_builtin_simple():
+    builtincode = """
+x = 1
+object None:
+    1
+def pass:
+    None
+"""
+    # construct the builtin module by running builtincode within the context of
+    # a new empty module
+    interpreter = Interpreter(builtincode)
+    w_module = interpreter.make_module()
+    # the parent of a normal module is the builtin module
+    builtins = w_module.getparents()[0]
+    assert builtins.getvalue('x').value == 1
+
+    ast = parse("""
+tx = x
+object a:
+    pass
+ax = a x
+""")
+    interpreter.eval(ast, w_module)
+    assert w_module.getvalue("ax").value == 1
+    assert w_module.getvalue("tx").value == 1
+
+
+def test_inttrait():
+    builtincode = """
+object inttrait:
+    x = 1
+    def maybe_fortytwo:
+        if self:
+            42
+        else:
+            x
+"""
+    interpreter = Interpreter(builtincode)
+    w_module = interpreter.make_module()
+    # the parent of a normal module is the builtin module
+    builtins = w_module.getparents()[0]
+    inttrait = builtins.getvalue("inttrait")
+
+    ast = parse("""
+x = 5 x # this returns 1, because it looks in the inttrait defined above
+m0 = 0 maybe_fortytwo
+m1 = x maybe_fortytwo
+inttrait x = 2
+m2 = 0 maybe_fortytwo
+tr = inttrait
+""")
+    interpreter.eval(ast, w_module)
+    x = w_module.getvalue("x")
+    assert w_module.getvalue("tr") is inttrait
+    # the inttrait is defined in the builtin module, so its __parent__ is that
+    # module
+    assert inttrait.getparents() == [builtins]
+    assert x.value == 1
+    assert x.getparents() == [inttrait]
+    assert w_module.getvalue("m0").value == 1
+    assert w_module.getvalue("m1").value == 42
+    assert w_module.getvalue("m2").value == 2
+
+
+def test_builtin_default():
+    ast = parse("""
+def sumupto(x):
+    r = 0
+    while x:
+        r = r add(x)
+        x = x add(-1)
+    r
+x = sumupto(100)
+""")
+    # the constructor is called without arguments, so the default builtins are
+    # used
+    interpreter = Interpreter()
+    # tests that the default inttrait defines a method ``add``
+    w_module = interpreter.make_module()
+    interpreter.eval(ast, w_module)
+    assert w_module.getvalue("x").value == 5050