Primitive Types

We distinguish three primitive types: (1) elementary types such as numeric values or strings; (2) arrays; and (3) records. Initially every declared variable gets a unique primitive type. Types are made unique by encoding a label into them: since variable occurrences must have unique names in a COBOL program (module), the variable names can be used for this. We qualify variable names with program names to obtain uniqueness at the system level. We use $T_A$ to denote the primitive type of variable $A$.