Tuples

Indexed tuples

Indexed tuple is a structure, which can contain several elements of arbitrary types and elements of which can be accessed by an index. The MPS implementation represents a tuple instance by a Java object. The usual meaning of '=' and '==' operations on Java objects within MPS remains unchanged.

[int, string] pair = [1, "a"];
int first = pair[0];
string second = pair[1];

Named tuples

Named tuples are similar to indexed tuples, with the difference that elements are accessed by name instead of by index. To use named tuples in the model you first need to explicitly define them in your model (new ->jetbrains.mps.baseLanguage.tuples/tuple).

(first, second)<string, int> pair = (first = "abcd", second = 1);

Declaration of Pair:

public tuple Pair<S, T> {
  S first;
  T second;
}

[public|protected|private] tuple tupleName<TypeVar, ...> {
  elementType elementName;
}