add-typep-transformer

Arguments: type function

This function is called for its side effects. The return value has no meaning. This function tells the compiler that a typep form:

can be transformed into the form:

The compiler will make the transformation where possible.

type must be a type, typically defined by the user with deftype. predicate should be a function object or a symbol naming a function. That function must accept any Lisp object as a single argument and return nil if the object is not of type type, true if it is of type type. remove-typep-transformer removes the transform.

See compiling.htm for general information on compiling and see Adding typep-transformers in that document for more information on typep transforms.

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This page was not revised from the 10.0 page.
Created 2019.8.20.