added howto + test

docs/howto.md

@@ -160,3 +160,16 @@ concrete DSL. These DLS reference each other.
 
  * Unittest
    [tests/functional/test_metamodel/test_multi_metamodel_refs.py](https://github.com/igordejanovic/textX/blob/master/tests/functional/test_metamodel/test_multi_metamodel_refs.py),
+
+## Enable and distinguish float and int values for attributes
+
+ * Model text:
+
+        x1 = 1
+        x2 = -1
+        y1 = 1.0
+        y2 = 1.1e-2
+        y3 = -1.1e+2
+
+ * Unittest 
+   [tests/functional/examples/test_modeling_float_int_variables.py](https://github.com/igordejanovic/textX/blob/master/tests/functional/examples/test_modeling_float_int_variables.py),

tests/functional/examples/test_modeling_float_int_variables.py

@@ -0,0 +1,39 @@
+from textx import metamodel_from_str
+
+
+def test_int_and_floats():
+    grammar = '''
+    Model: vars+=Var;
+    Var: name=ID '=' value=Val; 
+    Val: O_FLOAT|O_INT; // order matters: float first!
+    O_INT: intVal=MYINT;
+    O_FLOAT: floatVal=MYFLOAT;
+    MYINT: /\-?\d+/;
+    MYFLOAT: /\-?\d+.\d+([eE][-+]?\d+)?/;
+    '''
+    model_text = '''
+    x1 = 1
+    x2 = -1
+    y1 = 1.0
+    y2 = 1.1e-2
+    y3 = -1.1e+2
+    '''
+
+    mm = metamodel_from_str(grammar)
+    mm.register_obj_processors({
+        "MYINT": lambda x: int(x),
+        "MYFLOAT": lambda x: float(x)
+    })
+    m = mm.model_from_str(model_text)
+
+    assert 'O_INT'   == m.vars[0].value.__class__.__name__
+    assert 'O_INT'   == m.vars[1].value.__class__.__name__
+    assert 'O_FLOAT' == m.vars[2].value.__class__.__name__
+    assert 'O_FLOAT' == m.vars[3].value.__class__.__name__
+    assert 'O_FLOAT' == m.vars[4].value.__class__.__name__
+
+    assert 1 == m.vars[0].value.intVal
+    assert -1 == m.vars[1].value.intVal
+    assert abs(1.0 - m.vars[2].value.floatVal) < 1e-5
+    assert abs(1.1e-2 - m.vars[3].value.floatVal) < 1e-5
+    assert abs(-1.1e+2 - m.vars[4].value.floatVal) < 1e-5