List Literal Values in patterns

[okrosa]

The system accepts list literal values in pattern bodies (even with different values in it):

pattern MyPattern() {
 literalType == {10, "helloworld", true, 3.14};
}

[bergmanngabor]

Well, currently this is not very useful. However, I could imagine places where we could use list literals in the (far?) future.

How about an \in / element-of operator? E.g. to iterate over elements in a comma-separated list attribute: Element \in eval(S.split(","))

Now we can also use literal lists here, and even handle them more concisely and efficiently then constants in separate bodies:

pattern red(Deck, Card) = {
    find contains(Deck, Card);
    Card.suite(Card, Suite);
    Suite \in {HEARTS, DIAMONDS}; 
}

Instead of:

pattern red(Deck, Card) = {
    find contains(Deck, Card);
    Card.suite(Card, Suite);
    Suite == HEARTS; 
} or {
    find contains(Deck, Card);
    Card.suite(Card, Suite);
    Suite == DIAMONDS; 
}

Or:

pattern red(Deck, Card) = {
    find contains(Deck, Card);
    Card.suite(Card, Suite);
    find diamondsOrHearts(Suite); 
}
pattern diamondsOrHearts(Suite) = {
    Suite == DIAMONDS; 
} or {
    Suite == HEARTS;
}

(this latter form would be the closest to how such a literal list would behave with \in )

[ujhelyiz]

@bergmanngabor Don't mix issues. In the future, this feature might make sense, but before the release, this feature is more of a bug.

[ujhelyiz]

Updated grammar - it seems to disallow the lists in constraints. However, somehow the test framework does not know about this, so I could not create a test case that verifies this functionality.

I would be glad for some manual testing before closing this issue.

[ujhelyiz]

Of course, because of a grammar change a grammar regeneration is necessary.