callCC                 package:base                 R Documentation

Call With Current Continuation

Description:

     A downward-only version of Scheme's call with current
     continuation.

Usage:

     callCC(fun)

Arguments:

     fun: function of one argument, the exit procedure.

Details:

     'callCC' provides a non-local exit mechanism that can be useful
     for early termination of a computation.  'callCC' calls 'fun' with
     one argument, an _exit function_.  The exit function takes a
     single argument, the intended return value.  If the body of 'fun'
     calls the exit function then the call to 'callCC' immediately
     returns, with the value supplied to the exit function as the value
     returned by 'callCC'.

Author(s):

     Luke Tierney

Examples:

     # The following all return the value 1
     callCC(function(k) 1)
     callCC(function(k) k(1))
     callCC(function(k) {k(1); 2})
     callCC(function(k) repeat k(1))

