Landon Curt Noll
f64f244ba6
The largest change was due to modifying `ioccc.css` that resulted in all year and entry tarballs being modified. Ran `make update` to perform the above.
To build:
make
To use:
./prog
Try:
./try.sh
By default that will use indent(1) found by the shell type -P indent and
sed(1) found by the shell type -P sed but if you want to change these, say
to try a different beautifier, you can do it like:
INDENT=bcpp ./try.sh
which would change it to use bcpp(1) instead of indent(1). Do similar for
sed(1) only use the name SED.
Judges' remarks:
C11 features definitely help this entry to be as concise as it is.
The judges would like to think that they had almost understood how this entry works.
If you win a bet by demonstrating this entry, please let us know.
Author's remarks:
Remarks
- Computes the factorial function.
- No loops, no explicit recursion.
- Untyped C without any casts, using a
wword datatype. - Varargs not essential,
w(*)(w,w*)works just as well. - Conforming to ISO C.
- No warnings when compiled with
-std=c99 -Wall -Wextra -pedantic. - Comments in the code explain what this really is about.
- C as a functional programming language: untyped lambda calculus compiled to executable C functions.
- Untagged closures (just a function pointer followed by some values).
- Recursion implemented through Curry's paradoxical combinator
Y. - The readable implementation of
Yis on lines 29-30:
W_f = \x.f(xx)
Y = \f.W_f W_f
- A mixture of strict and lazy evaluation, with a
_force function (John Tromp notes that if Turing's fixed-point combinator(\xy.y\z.xxyz)(\xy.y\z.xxyz)had been used, all applications could have been strict). - Uses
Yto implement factorial on nativeints. - 10! seconds = 6 weeks.
- Answers the ultimate question of life, the universe and everything.