Cody Boone Ferguson
3deb7ae603
Amongst the changes here is that we do not need to have the hex or html
code (numbers) for open and close parentheses (in links) as there are
names. '(' is & followed by lpar; and the ')' is the same but 'rpar;'
instead. This makes it easier to remember and type and it generates the
same html as well (they are all valid). Now the markdown files are
consistent in this (in some cases hex was used and in others the html
code).
Although many markdown files were updated no html files needed to be
updated as it generates the same html. Even so I ran the appropriate
rules to do so just to verify this.
To build:
make
Bugs and (Mis)features:
The current status of this entry is:
STATUS: doesn't work with some platforms - please help us fix it
For more detailed information see 2011/richards in bugs.html.
To use:
echo expression | ./richards
Try:
./try.sh
Judges' remarks:
Oh no, yet another
dc-style calculator? (see
2000/dlowe using an embedded Perl interpreter and deemed Worst Abuse of the Rules). Well, this one does it (expression calculation, that is,
not the rule abuse) in a different way. The author claims that his calculator
does just-in-time compilation. What would you do to prove or disprove his claim
without attempting to unravel the source?
Author's remarks:
This is an implementation of the classic UNIX
dc command, the
reverse Polish
calculator. Actually it's a pretty bad implementation, since it only implements
32-bit integers (well, sizeof(int)-sized integers). It only implements the
commands +, -, *, /, p (only for numbers), register stacks, macros and
comparisons. Wow, you'd think I could've done better in 2K of code.
OH! I forgot to mention! It's a JIT.
Wait, don't stop reading! I know what you're thinking, platform-specific code is discouraged in IOCCC. But do you see any platform-specific code? There's no assembler here! This JIT works on a dozen platforms, and the only platform-specific assumptions it makes are that the stack grows down and integers are at least 32-bit.
You will probably get warnings while compiling the code. In particular:
-
If your system requires the inclusion of
alloca.hto use alloca, use the compile flag-DAH. -
If your system cannot use
mmap(), use the compile flag-DNM. -
I don't include any headers I don't strictly need to, so you'll get warnings about (at least)
memcpy(),isdigit(),atoi(),calloc(),malloc()andalloca()if you didn't use-DAH. - NOTE from judges: we added these includes in 2023. -
GCC likes to complain about
while (a = b)(assignments as a condition). -
I don't return from
main(), even though it's declared to returnint.
Platforms on which all known/tested optimization levels work with no additional flags:
- gcc 4.6.2 + x86[_64] + GNU/Linux, Mac OS X or Windows
- clang 2.9-16 + x86[_64] + GNU/Linux or Mac OS X
- tcc 0.9.25
- gcc 4.4.5 + alpha, arm, mips[el], powerpc[64], s390x (IBM zSeries)
- gcc 4.1.3 + vax + NetBSD
Platforms which work but not at all optimization levels or needing special flags:
- owcc 1.9 + x86 + Windows: Needs
-DNM -DAH -fno-stack-check - gcc 4.4.5 + sh4: -O0 works, higher optimization levels don't work for unknown reasons.