Entity-field date mentions

When you write “the day Lord Aerion was born” inline in a chapter, you have two choices:

1. Type a hardcoded date — Year 100, Day 5. The number is frozen the moment you type it. If you later edit Aerion’s recorded birth date, this paragraph still says Year 100, Day 5.
2. Insert an entity-field date mention — points the prose at Aerion’s birth_date field on his entity record. The next time anything renders the page, the mention re-reads the field and shows the current value.

Entity-field mentions are the second option. They’re how you keep prose accurate without manually re-grepping every chapter when you change an entity’s dates.

Note

This page covers the dynamic mention type. For typed-in dates without entity coupling, use Events (named one-time dates) or recurring patterns (named repeating dates).

When to use entity-field mentions

Use them whenever a date in your prose belongs to an entity:

• “Aerion was born in <his birth_date>.”
• “The temple was founded <n> years before Aerion’s death.”
• “On <the day Bran took the throne>, the rains stopped.”

Don’t use them for one-off historical events that aren’t owned by an entity — those go in the Events picker tab.

How to insert one

1. In the editor, type [[ to open the date picker, or select prose and pick Assign Date/Time… from the right-click menu.
2. Switch to the Entity tab.
3. Type the entity’s name. The picker shows entities that have at least one date-typed field, with each field’s current value next to it (Aerion · birth_date · Day 100).
4. Click the row you want. The mention is inserted in your prose, marked as entity_field.

How resolution works

Every time the page renders, MythTapestry re-fetches the referenced entity and reads the named field. The mention itself stores only (entity_id, field_name) — the value is computed live.

Situation	What you see
Field has a value	The current value, formatted using the world’s default calendar (or the calendar the mention is bound to)
Field is unset	”Unset” — the writer can fix it on the entity panel
Entity was deleted	”Entity not found — re-link the mention”
Field was renamed in the schema	”Field has been renamed — re-link the mention”

Resolution failures don’t break the page — they show inline so you can spot and fix them.

What you can see on the entity panel

Open any entity that has date-typed fields and look for the Dates tab in its sidebar. It lists every date field declared by the entity-type schema with the current value. This is the same list the picker offers, viewed from the entity’s side instead of the writer’s side.

Tip

The “used in N places” rollup — showing every chapter that references each date field — is on the way. Track issue #231 for the cascade preview, content-unit “mentioned dates” panel, and entity Timeline tab extension.

Field types that work

The picker offers any field declared in the entity-type schema with one of these types:

• date — a calendar date, integer absolute_day.
• datetime — date plus sub-day time.
• temporal — the world-calendar form, stored as {absolute_day, time_of_day}.

Strings and numbers that look like dates (e.g., a string field set to “1523”) are not offered — the schema needs to declare the field as a date type for the resolver to know how to read it.

What gets stored on the mention

Just two attributes, plus presentation metadata:

• entity_id — UUID of the referenced entity.
• entity_field — schema field name, e.g. birth_date.

That’s why edits to the entity’s value cascade automatically: the mention doesn’t carry a copy of the date, only the pointer to where the date lives.

Editing the underlying entity

When you change an entity’s date field via the entity panel, every entity-field mention pointing at that field will resolve to the new value the next time it’s rendered. There’s no batch update to wait for.

If you change a field type (e.g., switch a date field to string), or rename the field, existing mentions stop resolving and surface a re-link prompt.