LogicT- backtracking monad transformer with fair operations and pruning
tailof a functional stream
control0and others in terms of
div/4now reports finite failures in more situations (e.g., when trying to divide any odd number by two with the zero remainder).
(call/cc call/cc). First-class continuations can be tricky, therefore, being formal helps.
eval-uating open code
lambdaas a library syntax
lookup-def: Look up a value in alists of various formats and handle the look-up failure