Control Flow

make-promise

(make-promise thunk) -> promise

  thunk := procedure taking no args

Creates a promise.

(promise? obj) -> boolean

  obj := any object

Returns true if the object obj is a promise.

(call-with-parameters thunk . parameterization) -> any

  thunk := procedure taking no args

parameterization:
 parameter value ...

Calls thunk with parameterization.

(with-catch handler thunk) -> any

  handler, thunk := procedure

Calls thunk with handler as the exception catcher.

(with-unwind-protect thunk fini) -> any

  thunk, fini := procedure

Calls thunk, invoking fini when execution exits the dynamic extent of thunk.