Engineering Compiler

The System05 Compiler Type System defines the categories, properties, relationships, and permitted operations applicable to engineering information.

The Type System may include:

scalar and textual types;

Boolean and logical types;

identity and reference types;

numerical and dimensional quantity types;

geometric types;

temporal types;

lifecycle-state types;

component and interface types;

material types;

evidence and authority types;

collections;

optional, unknown, and alternative types;

domain-specific engineering types.

Nominal typing should be used where identity and declared engineering meaning are essential. Structural similarity alone shall not make two safety-significant types interchangeable.

The Type System shall support inheritance, composition, parameterization, constrained subtypes, and governed extensions without allowing extensions to weaken mandatory base-type requirements.

Conversions shall be explicit where information, precision, authority, or engineering meaning could be lost.

Unknown, incomplete, conflicting, and not-applicable values shall have formal representations rather than being treated as ordinary null values.

The Type System shall prevent invalid operations such as adding incompatible quantities, connecting incompatible interfaces, assigning a proposed state to an active-state field, or treating unverified evidence as certification.