declare ( spec -- )

Vocabulary

kernel.private

Inputs

spec	an array of class words

Outputs

None

Word description

Declares that the elements at the top of the stack are instances of the classes in spec.

Warning
The compiler blindly trusts declarations, and false declarations can lead to crashes, memory corruption and other undesirable behavior.

Examples

The optimizer cannot do anything with the below code:

2 + 10 *

However, if we declare that the top of the stack is a float, then type checks and generic dispatch are eliminated, and the compiler can use unsafe intrinsics:

{ float } declare 2 + 10 *

Definition

USING: kernel ;

IN: kernel.private

: declare ( spec -- ) drop ;