Landon Curt Noll
4ee4c731f7
While not strictly necessary, replacing the two ASCII tab characters in the markdown copyright comment makes it easier to detect problematic TAB indentation within markdown files. After this commit, only 90 markdown files have leading ASCII TAB characters. And again, while not strictly necessary, we can consider running expand on those 90 markdown files to see what effect that might have on the HTML files they produce. Replace leading ASCII TAB characters with multiples of 8 ASCII SPACE characters (the default action of the `expand(1)` tool) might have an negative effect on some HTML formatting where **hack-a-round** formatting was attempted to fix broken indentation caused by problematic ASCII TAB characters. Think of this as a baseline for evaluating leading TAB characters within markdown files. TODO: Consider either using `expand(1)` to replace leading ASCII TAB characters with multiples of 8 ASCII SPACE characters AND/OR modifying the appropriate `bin` tool to convert leading ASCII TAB characters into multiples of 8 ASCII SPACE characters.
114 lines
3.2 KiB
Markdown
114 lines
3.2 KiB
Markdown
## To build:
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``` <!---sh-->
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make
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```
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There is an alternate version of this entry. See [Alternate
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code](#alternate-code) below for more details.
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## To use:
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``` <!---sh-->
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./prog < textfile
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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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## Alternate code:
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Compare [prog.c](%%REPO_URL%%/2018/anderson/prog.c) and [prog.alt.c](%%REPO_URL%%/2018/anderson/prog.alt.c) and find out why we had to
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modify the entry, and what confused the author (see the author's remarks). No,
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it was not the shape of the Roman V that we, or the compiler, didn't like.
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### Alternate build:
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``` <!---sh-->
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make alt
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```
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### Alternate use:
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Use `prog.alt` as you would `prog` above.
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### Alternate try:
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``` <!---sh-->
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./try.alt.sh
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```
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## Judges' remarks:
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With this entry, you won't need to turn your monitor [upside
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down](http://en.wikipedia.org/wiki/River_%28typography%29)!
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## Author's remarks:
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### Compiling the program:
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``` <!---sh-->
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cc -Wall -Wextra -Wpedantic -O3 -std=c11 prog.c -o prog
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```
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Also works with a standard of C99, but C90/C89 will not compile due to
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`for` loop initial declarations, along with additional warnings about
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variable length arrays and lack of a `return` statement.
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### Additional info:
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This small program, when given text on `stdin`, will produce a pattern of
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squiggly lines. This pattern is deterministic, and it shouldn't be too
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difficult to determine from whence they come. There is even a comment
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that describes the highlighted phenomena in the source, for those that
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require a small nudge. With denser text blocks, such as an essay or
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similar prose, the output can be rather pretty, in an chaotic emergence
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sort of way. Try using this file, or the source file as inputs.
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In its current form, this program can handle lines of length 255; to
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adjust this limit, change the variable `a` at the top of the source.
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Other adjustments, such as the exact printed characters, are rather
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easy, once sufficient reverse engineering has occurred. Improvements
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such as proper handling of tabs are left as an exercise to the reader.
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In developing this program, the author found a potentially interesting
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bug. If the expression `(j=k,j)` (near the middle of the source) is
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changed to `(j=k,k)`, the program produces different output. The author
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used gcc 5.4.0, compiled for `x86_64-linux-gnu`. Enabling or
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disabling optimization produces the same results. The author is not
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sure who is the culprit, but instead shrugged and moved on with life.
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Of course, YMMV with your own environment.
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The structure of this program, as you may have deduced, is two `for`
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loops, one nested in the other. There are also a bunch of direct
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variable assignments, such as `j=k`. There is some filler fluff, such as
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`0-0+0`, but all that sort should be rather easy to spot. It was mostly
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added for the purpose of making certain things line up right, and only
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secondarily to obfuscate.
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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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