Context Tables

A declaration of the form

• 'table' T ( F₁ : T_n , ... , F_n : T_n )

A context table is an unbounded collection of entries. An entry has a unique key and a record of fields. These fields have names F₁, ..., F_n and types T₁, ..., T_n. The name of the table, T, acts as the name for the type of the keys.

A unique key is created by a key definition statement. The value of a field is defined by a context update and accessed in a context query.

	Example 'table' Label (Coordinate: INT) This defines a table Label. Entries of this table have one field with name Coordinate and type INT. Keys of entries have type Label. A value of type Label can be created without knowing the value of field Coordinate. Lab :: Label defines Lab as unique value of type Label. Lab'Coordinate <- Loc may be used later to define the field Coordinate. Lab'Coordinate -> Loc is used to access the field Coordinate.

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