Allow back to no be known at compile time. Use a simple implementation
of a queue, adapted from https://irreal.org/blog/?p=40.
Add a test of a with-bound back.
State clearly in the documentation that set-prev stores the value
of VAL found at the end of the loop cycle and that it does
not modify VAR until the specified loop cycle.
Allow
backto no be known at compile time. Use a simple implementation of a queue, adapted from https://irreal.org/blog/?p=40.with-boundback.State clearly in the documentation that
set-prevstores the value ofVALfound at the end of the loop cycle and that it does not modifyVARuntil the specified loop cycle.See all issue #194.