Name: Anonymous 2007-01-05 6:18
Obfuscated code = code purposely made more difficult.
dont dissapoint
dont dissapoint
#define d define
#d a include
#a <stdio.h>
#a <string.h>
#a <ctype.h>
#d p char*
#d P ,(p)
#d T(E) !strcmp(E,"()")
#d U return
#d W while
#d X sbrk(199)
#d z atof
#d e isspace
#d D A(_)
#d E S(C(_))
#d B(y) p y(_)p _;{
#d G(y,V) B(y)p i;U sprintf(i=X,"%lf",z(E)V z(S(C(D)))),i;}
p sbrk(),*S(),*j(),*O,*H;K,Y,M=14;double
z();Q(_)p _;{int V=0;W(e(*_))_++;H=_;W(V|!(e
(*H)|*H==')'||(*H=='('&&H-_)))V+=(*H=='(')-(*H==
')'),H++;U H-_;}B(C)U _++,Y=Q(_),_=strncpy(X,_,Y),_[
Y]=0,_;}B(A)_++,_+=Q(_);W(e(*_))_++;U O=X,*O='(',strcpy(
O+1,_),O;}B(Z)U _;}B(c)U C(E);}B(q)U A(E);}B(t)p i=E;U H=S(C
(D)),sprintf(O=X,T(H )?"(%s)":"(%s %s",i,H+1)
,O;}B(F)U S(C(A(T(E)?D:_)));}L(i,s)p
i,*s;{U isdigit(*i) ? z(i)!=z(s):strcmp(i,s);}
B(b)U L(E,S(C(D)))?"()":"t";}B(R)U E;}B(o)U z(E)<z(S(C(D)))?
"t":"()";}G(f,+)G(g,-)G(h,*)p r[4][2]={"function" P R,
"quote"P C,"lambda"P Z,"defun"P j};B(j)U r[M][1]=D,*
r[M++]=C(_);}p not[99][2]={"if"P F,"equal"P b,"<"
P o,"+"P f,"-"P g,"*"P h,"car"P c,"cdr"P q,
"cons"P t,"t","t"};B(S)int Li,s;p u;if(
isdigit(*_)|T(_))U _;for(Y=M;Y--;)
if(!strcmp(_,*r[Y]))U r[Y][1]
;u=E,_=D;if(*u-'(')U(*((p(*)())u)
)(_);s=Li=M;W(!T(_))r[M][1]=E,*r[M++]
="",_=D;O=C(u);W(!T(O))*r[Li++]=C(O),O=A(O);U O=S
(C(A(u))),M=s,O;}main(){H=O=X,Y=0;W(Y|!e(K=getchar()))K==
EOF?exit(0):0,Y+=(K=='(')-(K==')'),*H++=K;*H=0,puts(S(O))
,
main();{printf("XLISP 4.0\n");}}
Best of show:
Jari Arkko, Ora Lassila, Esko Nuutila
Laboratory of Information Processing Science
Helsinki University of Technology
Otakaari 1
02150 Espoo
Finland
Judges notes:
This is the most useful program entered this year. It is a
rather large subset of lisp. It has no error recovery, and
performs rather poorly in a number of cases. Even so, placing
all this functionality in such a small, densely packed program,
is impressive enough to win the Best of show award.
Selected notes from the author:
This program implements a Lisp interpreter in 1465 bytes of source.
Some sophisticated features supported, eg. functionals and recursion.
The special-forms/functions/variables implemented are:
+ - * < ()
car cdr cons defun equal
function if lambda quote t
Below are sample lisp expressions you might choose to try as input.
The program implements a conventional lisp listener, i.e. you type in
lisp expressions (followed by CR), the program evaluates them and
prints out the return values. End execution by typing an end-of-file
character.
(+ 2.5 3.1)
(defun fib (n)
(if (< n 2)
1
(+ (fib (- n 2)) (fib (- n 1)))))
(fib 10)
(defun ! (x) (if (equal x 0) 1 (* x (! (- x 1)))))
(! 7)
(defun fn1 (fn) (+ (fn 1 2) (fn 3 4)))
(defun fn2 (a b) (+ a b))
(fn1 (function +))
(fn1 (function fn2))
(fn1 (function (lambda (z1 z2) (+ z1 z2))))
(quote a)
(cons (quote (a b)) (quote (c d e)))
(cons (quote (f)) ())
(car (quote (a b c)))
(cdr (cdr (quote (g h i))))
Please do not leave any whitespace before the first parenthesis when
you type your input, or any other unnecessary whitespace. Please try to
avoid any undefined variables or functions, wrong number of arguments
etc. All these errors are likely to dump core (i.e. there are no error
checks in the program).
Traditional Lisp implementations use cons cells as the main data
structure. Lists are organized of pointer chains of these cells.
In this program, an alternate representation was chosen: char*'s.
All list operations, including the ones in the interpreter, are
made using string representations of the lists. These operations
must count parentheses and skip whitespace. This leads to extremely
poor performance!
Copyright (c) 1989, Landon Curt Noll & Larry Bassel.
All Rights Reserved. Permission for personal, educational or non-profit use is
granted provided this this copyright and notice are included in its entirety
and remains unaltered. All other uses must receive prior permission in writing
from both Landon Curt Noll and Larry Bassel.