The Fortress Language Specification - CiteSeerX

Chapter 6
Declarations
Declarations introduce named entities; we say that a declaration declares an entity and a name by which that entity
can be referred to, and that the declared name refers to the declared entity. As discussed later, there is not a one-one
correspondence between declarations and named entities: some declarations declare multiple named entities, some
declare multiple names, and some named entities are declared by multiple declarations.
Some declarations contain other declarations. For example, a trait declaration may contain method declarations, and a
function declaration may contain parameter declarations.
Syntactically, the positions in which a declaration may legally appear is determined by the nonterminal Decl in the
Fortress grammar, defined in Appendix G.
6.1 Kinds of Declarations
Syntax:
Decl ::= TraitDecl
| ObjectDecl
| FnDecl
| VarDecl
| DimUnitDecl
| TypeAlias
| TestDecl
| PropertyDecl
There are two kinds of declarations: top-level declarations and local declarations.
Top-level declarations occur at the top level of a program (or component), not within any other declaration or expression.
A top-level declaration is one of the following: 1
• trait declarations (see Chapter 9)
• object declarations (see Chapter 10), which may be parameterized or nonparameterized
• top-level function declarations (see Chapter 12), including top-level operator declarations (see Chapter 16)
1 The Fortress component system, defined in Chapter 22, includes declarations of components and APIs. Because component names are not used
in a Fortress program and API names are used only in qualified names and declarations of import and export , we do not discuss them in this
chapter.
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