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OperationDeclaration

OperationDeclaration[type,op,typedfun]

declares a typed function to be used for the operation op of type.

Details

OperationDeclaration is a symbolic representation of a declaration and does not evaluate on its own.
The typed function in OperationDeclaration can be of the form Typed[{t₁,t₂,…}t_out]@Function[{x₁,x₂,…},body].
Any operations declared for a type in a TypeDeclaration will need an OperationDeclaration for the type to be used.
The type in OperationDeclaration can be written polymorphically using ForAllType.
OperationDeclaration avoids the need to make up a name for a function used as an operation.

Examples

Basic Examples (1)

A declaration of a product type with one operation:

A declaration of the operation:

Compile a function to create an instance of the type and another to call the "Increment" operation:

Create the instance:

Call the "Increment" operation; the old value of 0 is returned:

Call the "Increment" operation again; now the old value is 1:

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