fpp/docs/users-guide/Defining-Framework-and-Dictionary-Definitions.adoc

== Defining Framework and Dictionary Definitions

=== Framework Definitions
*Framework definitions* are type and constant definitions that 
are specially used by the F Prime Framework. If a model defines 
framework definitions, they must conform to the rules described 
in the the _FPP Specification_.

To write a framework definition, we write the type or constant
and ensure that the definition follows the rules for that
framework definition.

For example, to write the `FwDpIdType` framework definition, 
we would write an alias `FwDpIdType` that represents an
integer type:

[source,fpp]
----
type FwDpIdType = U32
----

To write the `Fw.DpCfg.CONTAINER_USER_DATA_SIZE` framework definition, 
we would define modules `Fw` and `DpCfg` and write a constant
`CONTAINER_USER_DATA_SIZE` with an integer type:

[source,fpp]
----
module Fw {
    module DpCfg {
        constant CONTAINER_USER_DATA_SIZE = 1
    }
}
----

=== Dictionary Definitions

An FPP model may include type and constant definitions
that are *dictionary definitions*. These definitions describe
type and constant definitions that will be output to the 
dictionary.

To write a dictionary definition, prefix an array, struct, 
alias, or constant definition with the `dictionary` keyword.
For example, to define a constant dictionary definition 
we write the following:

[source,fpp]
----
dictionary constant a = 1
----

To define an array dictionary definition, we write the following:
[source,fpp]
----
dictionary array a = [3] U32
----