CSC173 Ballads

FLAT

A finite state automaton
Embarks upon a quest.
It reaches the next state each time
It sees the letter 's',
But every time it sees a 't'
It does one state regress.

If this automaton has seven
States before the last,
Will it have reached acceptance
By the time this string has passed?

-- D. Riley 2009

LOGIC

The agent's cunning and he's bold;
He's after all the wumpus gold!
With logic he can find his way
To squares wherein no dangers lay.

Is there a wumpus in that square?
If not, the agent wonders where
The wumpus lurks, and tries to find
A telltale stench that is its sign.

Is there a pit within that square?.
A breeze nearby suggests it's there
But which of these squares has the pit?
Logic can tell us which one's it!

The wumpus lurks within one square;
Others have pits. Does the agent dare
To brave the dark and smelly cave?
Yes; with logic, he'll be safe!

-- D. Riley 2009

LAMBDA CALCULUS

We open Computation's core:
Do we find wires when we explore?
Ones and zeroes? diode junctions?
Nope, there's no there there -- but functions!

Nameless functions start with lambda
After which the bound var's crammed, a-
Long with dot, and then the text
Of function body follows next.

Except when your reduction's eta,
Application starts with beta:
Real arg copied in for formal
If evaluation's normal.
(Use alpha since there's nothing shaming
In the need to do renaming).

We build logic (and, or, true),
Numbers, cons, car, cdr too,
Arithmetic, with a typed version,
Structures, conds, Y not recursion?

self copy self copy self copy self copy...
self self self self ... copy copy copy copy
When trapped in infinite regress
You'll never find a clear egress.

Just prevent it with abstraction,
Whose binding will delay the action,
And which when used on selfapply
Paradoxically yields Y.

Thus o'er the world we'd vainly search
To find one clever as A. Church.
Lambdas from his ivory tower
Match Turing's mechanistic power.

-- C. Brown 2009

SCHEME

 (define poetic-sum
   (lambda (number num)
      (if (< num 1) number
          (+ (poetic-sum
             (+ 1 number num)
             (- num 1)) num))))
D. Riley

MATLAB(TM)

diary delete shg,
pack sort flops ans svd.
num2str stairs atan2,
magic startup residue.

who cumsum qz qr?
i ans pi inf errorbar!
any mean & global plot
' == ^ ~ 

modred plotconfusion dare?
display brighten candle care!
placepole damp impulse feedback,
zoom off now get series stack.

weekday highlow amortise,
double softmax margin size!
fetch initial canon, mae;
maxdrawdown on thirdwednesday.

elseif break:  pause,  reshape spline,
echo toeplitz, return sin.
finite polar fft,
contour logspace std.

if delete isstruct for sum,
save what load type hex2num.
hadamard null polyfit?
error help clear exit quit!
--C. Brown 2009

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Last update: 6/16/09