//
// mapValues
//

function mapValues;
overload mapValues('f, 'first, ...'rest) = f(first), ...mapValues(f, ...rest);
overload mapValues('f) = ;



//
// clay types as symbols
//

symbol Bool;
symbol Int;
symbol Array[T,n];
symbol Tuple[...T];

symbol RecordTag;

recordType(...'fields) = (RecordTag, fieldNames(...fields), fieldTypes(...fields));
fieldNames(...'fields) = (...mapValues(f => tupleElement(f, 0), ...fields));
fieldTypes(...'fields) = (...mapValues(f => tupleElement(f, 1), ...fields));

record?('t) =
    symbolWithBody?(t)
    and tupleWithTag?(symbolBody(t), RecordTag);

symbolWithBody?('x) = symbol?(x) and symbolHasBody?(x);

tupleWithTag?('x, 'tag) =
    tuple?(x)
    and lesser?(0, tupleSize(x))
    and equals?(tupleElement(x, 0), tag);

recordFieldCount('t | record?(t)) = tupleSize(tupleElement(symbolBody(t), 1));
recordFieldNames('t | record?(t)) = tupleElement(symbolBody(t), 1);
recordFieldTypes('t | record?(t)) = tupleElement(symbolBody(t), 2);


symbol Point[T] = recordType(
    ("x", T),
    ("y", T),
);

recordInfo('t | record?(t)) = (t, recordFieldNames(t), recordFieldTypes(t));

main() = recordInfo(Point[Int]);