Fixed Values
Reference: This page is a source-based technical synthesis of the LaTeX chapter cited below. For exact syntax, availability or ABI signatures, verify the versioned source, manifest and executable tests.
Scope and source boundary
A fixed-value constraint is a validity restriction rather than a convenience initial value.
Declarative constraints express validity in the model rather than scattering equivalent tests through views and controllers. The source chapters cover defaults, fixed restrictions, role/type domains and validation boundaries. A default is a proposed value when a value is absent; a fixed requirement constrains what can be accepted.
Engineering rules
- Separate a defaulting rule from a hard validity rule.
- Associate a constraint with the appropriate concept, relation, role or action context.
- Validate values when they enter the model and at authoritative action boundaries.
- Add positive and negative semantic tests instead of trusting UI hints alone.
Chapter outline (original LaTeX headings)
- Concept Constraints
- Participant Typing and Role Paths
- Defaults
- Nullability
- Action Parameter Contracts
- Fixed Business Invariants
LaTeX provenance
Primary chapter: Declarative Conceptual Programming with the logiCells Platform/developer-guide/chapters/constraints-defaults-and-validity.tex.