Rosencrantz and Ethernet (2014)

I think that I shall never see A matrix lovely as a tree. Trees are fifty times as fun As structures a la PL/I (Which Dijkstra claims are too baroque). And SNOBOL's strings just can't compare With all the leaves a tree may bear. And COMIT strings are just a joke. Vectors, tuples too, are nice, But haven't the impressive flair Of trees to which a LISP is heir. A LISPer's life is paradise!

Many people think that JOSS And others, too, are strictly boss; And there are many BASIC fans Who think their favorite language spans All that would a user please. Compared to LISP they're all a loss, For none of them gives all the ease With which a LISP builds moby trees.

RPG is just a nurd (As you no doubt have often heard); The record layouts are absurd, And numbers packed in decimal form Will never fit a base-two word Without a veritable storm Of gross conversions fro and to With them arithmetic to do. And one must allocate the field Correct arithmetic to yield, And decimal places represent Truncation loss to circumvent: Thus RPG is second-rate. In LISP one needn't allocate (That boon alone is heaven-sent!) The scheme is sheer simplicity: A number's just another tree. When numbers threaten overflow LISP makes the number tree to grow, Extending its significance With classic treelike elegance. A LISP can generate reports, Create a file, do chains and sorts; But one thing you will never see Is moby trees in RPG.

One thing the average language lacks Is programmed use of push-down stacks. But LISP provides this feature free: A stack - you guessed it - is a tree. An empty stack is simply NIL. In order, then, the stack to fill

A CONS will push things on the top; To empty it, a CDR will Behave exactly like a pop. A simple CAR will get you back The last thing you pushed on the stack; An empty stack's detectable By testing with the function NULL. Thus even should a LISPer lose With PROGs and GOs, RETURNs and DOs, He need his mind not overtax To implement recursive hacks: He'll utilize this clever ruse Of using trees as moby stacks. Some claim this method is too slow Because it uses CONS so much And thus requires the GC touch; It has one big advantage, though: You needn't fear for overflow. Since LISP allows its trees to grow, Stacks can to any limits go.

COBOL input is a shame: The implementors play a game That no two versions are the same. And rocky is the FORTRAN road One's alpha input to decode: The FORMAT statement is to blame, But on the user falls the load. And FOCAL input's just a farce; But all LISP input comes pre-parsed! (The input reader gets its fame By getting storage for each node From lists of free words scattered sparse. It parses all the input strings With aid of mystic mutterings; From dots and strange parentheses, From zeros, sevens, A's and Z's, Constructs, with magic reckonings, The pointers needed for its trees. It builds the trees with complex code With rubout processing bestowed; When typing errors do forebode The rubout makes recovery tame, And losers then will oft exclaim Their sanity to LISP is owed - To help these losers is LISP's aim.)

The flow-control of APL And OS data sets as well Are best described as tortured hell. For LISPers everything's a breeze; They neatly output all their trees With format-free parentheses And see their program logic best By how their lovely parens nest. While others are by GOs possessed, And WHILE-DO, CASE, and all the rest, The LISPing hackers will prefer With COND their programs to invest And let their functions all recur When searching trees in maddened quest.

Expanding records of fixed size Will quickly programs paralyze. Though ISAM claims to be so wise In allocating overflow, Its data handling is too slow And finding it takes many tries. But any fool can plainly see Inherent flexibility In data structured as a tree. When all their efforts have gone sour To swell fixed records, losers glower. But list reclaimers hour by hour By setting all the garbage free Yield CONSequent capacity: Thus trees indefinitely flower. (And trees run on atomic power!)

To men of sensibility The lesson here is plain to see: Arrays are used by clods like me, But only LISP can make a tree.

            - The Great Quux
                (with apologies to
                   Joyce Kilmer)