See section Memoized Expressions for how to read memoized expressions. There are several SLIB macros which so useful that SCM automatically loads the appropriate module from SLIB if they are invoked. Traces the top-level named procedures given as arguments. Turns tracing off for its arguments. Print writes all its arguments, separated by spaces.
Print outputs a newline at the end and returns the value of the last argument.
Sometimes more elaborate measures are needed to print values in a useful manner. PSD runs slowly, so start by instrumenting only a few functions at a time.