Default 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 default fills an unspecified value under a declared rule; it is not proof that all values equal that default.
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.