Files
ioccc/2011/richards
Landon Curt Noll 7712db4a17 Expand all leading tabs in markdown files
Given how problematic leading tabs in markdown files can be,
we have expanded all leading tabs in markdown files by:

```sh
find * -type f -name '*.md' -print |
  while read -r file; do
    rm -f "$file.tmp" ;
    expand < "$file" > "$file.tmp" ;
    mv -f -v "$file.tmp" "$file" ;
  done
```

Given the previous changes to `bin/pandoc-wrapper.sh` and other recent
commits and recent pull requests, the were were **NO** changes to
any HTML files.  This is a **good thing** as the expression goes.

No there are no leading tabs in any markdown files.
A check to catch any re-introduction of leading tabs
into any markdown file is on the way.

BTW: We do not have anything against leading tabs in files,
even though we have had to deal with their impact on forming
HTML from markdown files (as well as the calc source code).
It is just that this is one of those cases where tabs conflict
(sometimes caused by people wanting to change the classic
8-space tab model) with a desired outcome.

Perform `make www` to perform the above and test under macOS.
2024-06-24 11:57:35 -07:00
..
2024-03-13 00:38:46 -07:00
2023-05-08 04:36:28 -07:00
2023-07-06 21:49:38 -07:00

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

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.h to 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() and alloca() 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 return int.

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.