Landon Curt Noll
7712db4a17
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.
107 lines
3.6 KiB
Markdown
107 lines
3.6 KiB
Markdown
## To build:
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``` <!---sh-->
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make
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```
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## To use:
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``` <!---sh-->
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echo something | ./anderson
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```
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## Try:
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``` <!---sh-->
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./try.sh
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```
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## Judges' remarks:
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This small program might be a nice addition to a digital personal
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organizer; just in case you are stranded on a desert island and need to
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signal your distress to passing ships.
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The obfuscation in this program is truly masterful. The program is
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very cleverly obscured without the use of a single `#define`!
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Reformatting this program by hand :-) is the easiest way to understand
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what is going on.
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### Note about `#define`s not being used:
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In 2023 due to annoying warnings triggered at different times, sometimes
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interspersed with the output of the program (this happens in macOS), many
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entries were changed to use `fgets(3)` instead. However to make the entries more
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like the original we redefined `gets` to use `fgets`. Unfortunately it's not
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possible to do it through `-Dfoo` compiler options so there is a `#define` in
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the code now.
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## Author's remarks:
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This program is a simple filter that translates ASCII text into
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semaphore code. It reads from standard input and converts all
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alphanumeric characters to their corresponding semaphore codes.
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Consecutive whitespace is translated as a single 'break' code. Newlines
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also cause the next code to be output on a new line. All other
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characters are ignored. The codes themselves are written to standard
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output as a depiction of a person holding two flags, using only ASCII
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characters (semaphore smileys, if you will). For example, given the
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input "Hello, world!", the output will be:
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```
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<> <> <> <> <> <>
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_() ()/ ()/ ()/ _\) () (/_ _\)
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[] /^ |^^ /^^ /^^ [] ^^ |^^| ^^ [] [] ^^
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<>[ [][ <>][ <>][ ][ [][] ][ ][
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<> []
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_()_ ()/ |() ()
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[] ^^ [] /^^ ^^| |^^|
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][ <>][ ][] [][]
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```
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The program is obfuscated without the use of the preprocessor or any
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special compilation parameters. In fact, the program doesn't even
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bother using any keywords, save the single `char` at the beginning.
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This program was crafted using only operator precedence rules,
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short-circuit evaluation and recursion. Each function contains a
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single, non-empty statement. (I did have to add a couple of empty
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statements to format the code properly.) There is a single string
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constant which encodes the flag positions and other data needed for
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drawing the semaphore codes.
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The preprocessor will provide no help in de-obfuscating this code, and a
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C beautifier won't get you very far either. You just have to crunch
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through it.
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An ANSI C compiler will generate several warnings when it compiles this
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program, as none of the functions declare their return type, nor do they
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return anything. This was necessary to keep the program free of
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keywords. It's valid in K&R C, and compiles in ANSI C. There are also
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warnings about conversion from `int` to `char` and the resulting loss of
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data. Again, if it's OK with K&R, it's OK with me.
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This program is a great teaching tool for learning the semaphore code;
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and if you don't have any flags handy you can just use two copies of the
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source file.
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<!--
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Copyright © 1984-2024 by Landon Curt Noll. All Rights Reserved.
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You are free to share and adapt this file under the terms of this license:
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Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
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For more information, see:
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https://creativecommons.org/licenses/by-sa/4.0/
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-->
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