[{"_class": "Datatype", "name": "String"},
{"_class": "Class", "name": "Expression", "abstract": true},
{"_class": "Class", "name": "Sqrt", "superTypes": "Expression", "features":
{"_class": "Feature", "name": "expr", "kind": "containment", "lowerLimit": 1, "upperLimit": 1, "type": "Expression"}},
{"_class": "Class", "name": "Fraction", "superTypes": "Expression", "features": [
{"_class": "Feature", "name": "expr1", "kind": "containment", "lowerLimit": 1, "upperLimit": 1, "type": "Expression"},
{"_class": "Feature", "name": "expr2", "kind": "containment", "lowerLimit": 1, "upperLimit": 1, "type": "Expression"}]},
{"_class": "Class", "name": "Mult", "superTypes": "Expression", "features": [
{"_class": "Feature", "name": "expr1", "kind": "containment", "lowerLimit": 1, "upperLimit": 1, "type": "Expression"},
{"_class": "Feature", "name": "expr2", "kind": "containment", "lowerLimit": 1, "upperLimit": 1, "type": "Expression"}]},
{"_class": "Class", "name": "Plus", "superTypes": "Expression", "features": [
{"_class": "Feature", "name": "expr1", "kind": "containment", "lowerLimit": 1, "upperLimit": 1, "type": "Expression"},
{"_class": "Feature", "name": "expr2", "kind": "containment", "lowerLimit": 1, "upperLimit": 1, "type": "Expression"}]},
{"_class": "Class", "name": "Neg", "superTypes": "Expression", "features":
{"_class": "Feature", "name": "expr", "kind": "containment", "lowerLimit": 1, "upperLimit": 1, "type": "Expression"}},
{"_class": "Class", "name": "Value", "superTypes": "Expression", "features":
{"_class": "Feature", "name": "value", "kind": "attribute", "lowerLimit": 1, "upperLimit": 1, "type": "String"}}]
Discards existing model!