Parameter specifications are typically used for prototype declarations, but also in methods as SELECT or GROUP_BY. A parameter specification support three functions:
- it defines the parameter types, which is necessary for implicit data conversion.
- it provides a name, which can be used for referring to the parameter
- It provides an assigned value, which can be used as default or initial value, but also as assignment rule.
parm_spec := [simple_type_spec] [ref_symbol(*)] identifier [fixed_array_size(*)] assigned_value