Language basics / Types |
Define a type as a synonym for an existing data type, or as a shortcut for records and array structures.
After declaring a type, it can be used as a normal data type to define variables.
TYPE t_customer RECORD cust_num INTEGER, cust_name VARCHAR(50), cust_addr VARCHAR(200) END RECORD ... DEFINE c1 t_customer ... DEFINE o1 RECORD order_num INTEGER, customer t_customer, ... END RECORD ... DEFINE custlist DYNAMIC ARRAY OF t_customer
The scope of a type is the same as for variables and constants. Types can be global, module-specific, or local to a function.
A good practice is to define types that belong to the same domain in a single .4gl module, and import that module in the modules where the types are needed.
By default, module-specific types are private; They cannot be used by an other module of the program. To make a module type public, add the PUBLIC keyword before TYPE. When a module type is declared as public, it can be referenced by another module by using the IMPORT instruction.