=== Dictionary Definitions

If the optional keyword `dictionary` appears in a type definition or
a constant definition, then that definition is called a
*dictionary definition*.
A dictionary definition instructs the code generator to include
the definition in the ground dictionary.

==== Semantics

If a type definition _D_ is a dictionary definition, then the type
defined by _D_ must be a <<Types_Displayable-Types, displayable type>>.

If a constant definition _D_ is a dictionary definition, then the
expression appearing in _D_ must have one of the following types:

* A <<Types_Primitive-Types,primitive type>>.
* A <<Types_String-Types,string type>>.
* An <<Types_Enum-Types,enum type>>.

==== Examples

[source,fpp]
----
dictionary type T = U32
dictionary array A = [3] string
dictionary constant a = 0

enum E { X, Y }
dictionary constant b = E.X

type T1
dictionary type T2 = T1 # Error: T2 is not displayable

# Error: c does not have primitive, string, or enum type
dictionary constant c = { x = U32 }
----