just look at the fib example:
>> fib = 1 : 1 : [a + b | (a, b) <- zip fib (tail fib)]
while(*s1++ = *s2++);
(λ 1 1) (λ (λλλ 1 (λ 1 (λ 4 (λλλ 3 1 (2 (λ 2)))) (4 (λ 5 (λ 5 (2 1)))))) (1 1)) (λ 1)
(in de-Bruijn notation) which, given a list of input bits,
parses the encoding of an arbitrary algorithm (as a combinator over the minimal single point basis λxλyλz.x z (y (λt.z))) from this bit stream, and runs that algorithm on the remaining input.
What makes it beautifull in my mind is the same thing that makes some poems beautifull - the fact that it seems simpler than the problem it solves, and yet it solves it well. If it evokes that surprising feeling of "That's it? That's enough?" - then it's beautifull, like a poem which expresses complex feeling in a few short verses.
For me Floyd-Warshall is one example.
Succinctness - expressing trees with as little bits as entropically possible. The representation is as simple as it could be - simply write down nested parentheses whose abstract syntax tree is your given tree. Practically all tree operations in logarithmic or constant time. How it works - recursively with range-min trees and range-max trees - simple and elegant number theory.
A primer - https://arxiv.org/pdf/0905.0768
I find especially all their slight variations to be quite poetic.
traverse(node):
if node:
[
...traverse(node.left),
...traverse(node.right),
node.value,
]
The pseudo-code recursively produces a list of the node values in post-order.
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 Hair
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 tree-like 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.
Its 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.
(would there then be algorithms as beautiful as an argument, or functions as beautiful as an idea?)
proc gcd(n,m): do n>m ⇒ n:=n-m ⫿ m>n ⇒ m:=m-n od; return max(n,m)
EDIT: note the different levels of abstraction: this is a program which implements a particular GCD algorithm, in a manner attempting to reflect the symmetry of the function which that algorithm calculates.
...Roger Hui: In the year 2033 Earth was discovered by Survey Fleet MCXII of the Galactic Empire. The Emperor ordered Earth to send a representative to the court, with strict instructions to “bring something beautiful”.
Emperor
What beautiful things does Earth have?
Earth Representative Your excellency, our...
Mergesort is quite beautiful I think. There’s something beautiful in the simplicity of just merging the sorted lists. Stable. No pathological cases. Nice access patterns.