Ordfoss

EffectiveField.h header

#include <ew/core/project/EffectiveField.h>

Namespace ew::core::project

EffectiveField struct

struct ew::core::project::EffectiveField

One property an entity effectively has, together with where it was declared.

Provenance is not decoration: a writer looking at a property needs to know whether editing it changes one entity or every entity in a category, and a tool that offers to promote or demote it needs to know which end it currently lives on. Deriving that afterwards would mean re-walking the ancestry with a second copy of the composition rule, which is exactly how the answer and the explanation of the answer drift apart.

Exactly one of the two sources is set. ew::core::project::Project::effectiveFieldSourcesFor produces these; ew::core::project::Project::effectiveFieldsFor is the same walk with the provenance dropped.

Members

ew::core::taxonomy::FieldDefinition ew::core::project::EffectiveField::definition

The property itself, as it survived the walk – the declaration that won on its key.

ew::core::foundation::CategoryId ew::core::project::EffectiveField::sourceCategory

The category that declared it, or a null id when an entity did.

ew::core::foundation::ContentId ew::core::project::EffectiveField::sourceEntity

The entity that declared it as its own, or a null id when a category did.

ew::core::foundation::CategoryId ew::core::project::EffectiveField::membership

The MEMBERSHIP this property arrived through: the entity's primary category, or one of its additional ones. Null when the entity declared the property itself.

Distinct from sourceCategory, which names the category that DECLARED it – possibly an ancestor several levels up. This names the one the writer put on the entity, which is what they would have to remove to lose the property, and what a label saying "from Cursed Object" has to be built from.

bool ew::core::project::EffectiveField::shadowed = false

Whether another membership also declared this key and lost.

First wins by membership order, and the loss is REPORTED rather than silent: two categories that both declare "weight" mean different things by it often enough that quietly taking one is how an entity ends up showing a number nobody wrote.