We’re continuing through pretty-printing, and now we’ve come to pprint-exit-if-list-exhausted.  This local macro is only useful in the context of the pprint-logical-block and pprint-pop features, so there will be more discussion of this in upcoming articles.

When, within a pprint-logical-block block, the pprint-exit-if-list-exhausted local macro is invoked, the logical block prints its defined suffix, and then program flow exits the block.  It is forbidden to call pprint-exit-if-list-exhausted when not within a pprint-logical-block block.