39 lines
2.1 KiB
Markdown
39 lines
2.1 KiB
Markdown
# ww: count words in 50 lines of C
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## Desiderata
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- Simplicity: Just count words, as delimited by: spaces, tabs, newlines.
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- No flags.
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- Avoid off-by-one errors.
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- Allow piping, as well as reading files.
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- Small.
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- Linux only.
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## Comparison with wc.
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The GNU utils version ([github](https://github.com/coreutils/coreutils/tree/master/src/wc), [savannah](http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=blob;f=src/wc.c;hb=HEAD)) is a bit over 1K lines of C. It does many things and checks many possible failure modes.
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The busybox version ([git.busybox.net](https://git.busybox.net/busybox/tree/coreutils/wc.c)) of wc is much shorter, at 257 lines, while striving to be [POSIX-compliant](https://pubs.opengroup.org/onlinepubs/9699919799/), meaning it has flags.
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The plan9port version of wc ([github](https://github.com/9fans/plan9port/blob/master/src/cmd/wc.c)) implements some sort of table method, in 352 lines. So does the [plan9](https://9p.io/sources/plan9/sys/src/cmd/wc.c) version, which is worse documented, but shorter.
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[Here](https://github.com/dspinellis/unix-history-repo/blob/Research-V7-Snapshot-Development/usr/src/cmd/wc.c) is a version of wc from UNIX V7, at 86 lines, and allowing for both word and line counts. I couldn't find a version in UNIX V6. Of all the versions, I think I understand this one best.
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## Steps:
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- [x] Look into how C utilities both read from stdin and from files.
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- [x] Program first version of the utility
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- [x] Compare with other implementations, see how they do it, after I've read my own version
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- [x] Compare with gnu utils.
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- [x] Compare with musl/busybox implementations,
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- ~~Maybe make some pull requests, if I'm doing something better? => doesn't seem like it~~
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- [ ] Install to ww, but check that ww is empty (installing to wc2 or smth would mean that you don't save that many keypresses vs wc -w)
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- ~~[ ] Could use zig? => Not for now~~
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- [ ] Look specifically at how other versions
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- [ ] Distinguish between reading from stdin and reading from a file
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- If it doesn't have arguments, read from stdin.
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- [ ] Open files, read characters.
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- [ ] Write version that counts lines
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- [ ]
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