In most cases the mask of a subexpression is formed by and-ing the masks of its operands. It is fully explained in a later section . All these data types can be used for scalars and lattices. LEL will do automatic data type promotion when needed. E.g. when a Double and a Complex are used in an operation, they will be promoted to DComplex.
Region is a specific data type.
A Float constant can be any integer or floating-point number. A Double constant is a floating-point number using a D for the exponent. The imaginary part of a Complex or DComplex constant is formed by a Float or Double constant immediately followed by a lowercase i . A full complex constant is formed by adding another constant as the real part. They form a Double constant, so when using e.g. pi with a Float lattice, it could make a lot of sense to convert pi to a Float.