Implementation

Implementation blocks enable method-call syntax.

Implementation Block

<impl_block> ::=
    "impl" <ident> [<type_parameters>] [":" <ident> [<type_parameters>]] "{"
        (
            | <function_assignment>
            | <constant_assignment>
            | <type_assignment>
        )*
    "}"

Dependencies:

• <ident>
• <type_parameters>
• <function_assignment>
• <constant_assignment>
• <type_assignment>

The <impl_block> is the implementation block for a give type. The type identifier is optionally followed by type parameters then optionally followed by a "for" clause. The "for" clause contains trait identifiers and optional type parameters for the traits. Followed by this is a list of function, constant, and type assignments delimited by curly braces.

Semantics

Associated functions, constants, and types are defined for a given type. If the type contains any generics in any of its internal assignments, the type parameters must be brought into scope by annotating them directly following the type's identifier.

If the impl block is to satisfy a trait's interface, the type's identifier and optional type parameters are followed by the trait's identifier and optional type parameters. In this case, only associated functions, constants, and types that are declared in the trait's declaration may be defined in the impl block. Additionally, all declarations in a trait's declaration that are not assigned in the trait's declaration must be assigned in the impl block for the given data type.