README: add CONTRIBUTING mention

CONTRIBUTING

@@ -99,17 +99,247 @@ notice:
 Style
 =====
 
-Make sure lines never exceed 80 columns in width when using four-character
-indentation steps. This helps contributors with smaller screens, those using
-side-by-side editor windows or panes, and those who have no text wrapping in
-their editor or terminal.
+“Everyone knows that debugging is twice as hard as writing a program in the
+first place. So if you’re as clever as you can be when you write it, how
+will you ever debug it?”
+	– Brian Kernighan, The Elements of Programming Style
 
-For usage text and help messages, do not implement a -h option. Instead, print
-usage information when any erroneous option is specified. Follow the NetBSD
-style guide for the usage text’s output format [0].
+The following guidelines are conducive to clear and readable code that is
+consistent with the style of the rest of the Bonsai Computer System.
+
+Use:
+
+ 0. A single line for control flow statements short enough to be easily
+ understood at a glance:
+
+	if !(argc < 0) { usage(program_name); }
+
+ This applies to C switch statements and cases and Rust match statements, as
+ well:
+
+	switch (value) { /* aligning stuff to make it easier to read is fine */
+		case possibility: variable = foo;  break;
+		default:          variable = NULL; break;
+	}
+
+ 1. Switch cases in C and match arms in Rust should start another level of
+ indentation:
+
+	switch (value) {
+		case possibility:
+			statement;
+			break;
+		default:
+			statement;
+			break;
+	}
+
+	match result {
+		Ok(n) => variable = n,
+		Err(e) => error = e,
+	}
+
+ 2. Braces in control flow where their inclusion is left optional in C:
+
+	if (condition) { statement; }
+
+ 3. Empty lines between different kinds of statements:
+
+	int t;
+
+	assert(io->bufuse > 0);
+	assert(io->bufuse <= io->bs);
+
+	if ((t = write(io->fd, io->buf, io->bufuse)) < 0) {
+		io->error = errno;
+		t = 0;
+	} else if (t > 0) {
+		memmove(io->buf, &(io->buf)[t], (io->bufuse -= t));
+	}
+
+	io->bytes += t;
+	io->prec  += (t > 0 && io->bufuse > 0);
+	io->rec   += (t > 0 && io->bufuse == 0);
+
+	return io;
+
+ 4. Compiler options that yield the most useful warnings, such as -Wpedantic in
+ a lot of C compilers. Fix the warnings, too [0].
+
+ 5. One more level of indentation and one argument per line when a function
+ call or statement header is too long to fit on one line:
+	let usage = format!(
+		"Usage: {} [-d delimiter] index command [args...]",
+		argv[0],
+	);
+
+ 6. One more level of indentation than the keyword that initiated a multi-line
+ block.
+
+	if (condition) {
+		statement;
+		statement;
+	}
+
+ 7. The return value of all non-void functions, or explicitly ignore them (like
+ casting to void in C) [0]:
+
+	if ((a = malloc(sizeof char)) == NULL) {          /* handle this error */
+		(void)fprintf(stderr, "oh noes!");   /* explicitly ignore this one */
+		return EX_OSERR;       /* ...because the program is exiting anyway */
+	}
+
+ 8. The smallest possible scope for data [0].
+
+ 9. Comments noting all the symbols and macros used from a C header file, next
+ to its include macro:
+
+	#include <unistd.h> /* close(2), getopt(3), lseek(2), read(2), write(2),
+	(space-aligned)      * optarg, optind, STDIN_FILENO, STDOUT_FILENO */
+
+ 10. Spaces in control flow statements, after the keyword and before the
+ opening brace:
+
+	for (i = 2; i < argc; ++i) {
+
+
+ 11. In Rust, a trailing comma on all arguments or fields that are on their own
+ lines:
+
+	return Err(EvaluationError {
+		message: format!("{}: Invalid token", i),
+		code: EX_DATAERR,
+	})
+
+ 12. In Rust, place extern statements after use statements that include standard
+ library crates. Group like statements:
+
+	use std::fs::Path;
+
+	extern crate strerror;
+	extern crate sysexits;
+
+	use strerror::StrError;
+	use sysexits::{ EX_OSERR, EX_USAGE };
+
+ 13. If text is on the same line as a brace, spaces after an opening brace and
+ before a closing one:
+
+	use sysexits::{ EX_DATAERR, EX_IOERR, EX_UNAVAILABLE, EX_USAGE };
+
+ 14. Alphabetic sorting, where applicable:
+
+	use std::io::{ BufWriter, Read, Write, stderr, stdin, stdout }
+
+ 15. In Rust, use the to_owned() method on string types (str, OsStr, CStr, etc.)
+ and the to_string() method on other types.
+
+
+Avoid:
+
+ 16. Unbounded loops [0].
+
+ 17. Function pointers [0].
+
+ 18. Heap memory allocation [0].
+
+ 19. Using too much nested logic (within reason).
+
+ 20. Too many levels of dereferences [0]:
+
+	/* do not do this */
+	for (size_t i = 0; i < sizeof a / sizeof *a; ++i) {
+		if (a[i].id == MATCH) { a[i].val = 0; }
+	}
+
+	/* do this */
+	for (struct MadeUp *s = &a[0]; *s != NULL; s = &s[1]) {
+		if (s->id == MATCH) { s->val = 0; }
+	}
+
+ 21. Using C preprocessor macros; the fewer, the better [0].
+
+ 22. The exit(3p) and std::process::exit() functions; returning from the main
+ function skips a system call.
+
+
+Do not use:
+
+ 23. More than the length of one printed page for a function [0].
+
+ 24. Recursion, as it’s complex and can unexpectedly overflow the stack [0].
+
+ 25. Any functionality not in the POSIX C specification and language features not
+ in C99.
+
+ 26. Do-while loops, as they’re unique to C and confusing for casual programmers.
+
+ 27. Labels and goto statements; use sensible flow control [0].
+
+ 28. Pointer arithmetic, as it tends to be confusing and unnecessary; use
+ index-reference patterns like &p[1] instead of p + 1. &p[n] is the address at
+ p + sizeof p * n, not p + n, like pointer arithmetic suggests.
+
+ 29. C struct bitfields in unions, to access certain bits of bigger data types,
+ as it’s poorly defined in the C standards; use bit arithmetic.
+
+ 30. C trigraphs.
+
+ 31. Inclusions in C header files, to prevent multiple file inclusions.
+
+ 32. C preprocessor variables to prevent multiple inclusions of the same file,
+ such as:
+
+	#ifdef _FILE
+	#define _FILE
+	/* file body */
+	#endif /* ifdef _FILE */
+
+ Instead, take the time to ensure other files aren’t including any files twice.
+
+ 33. The gets(3p) function from <stdio.h>, as it’s impossible to prevent buffer
+ overflows when it's used; use fgets(3p) from <stdio.h>.
+
+ 34. The scanf(3p) function from <stdio.h> [1].
+
+ 35. Any functionality not described in the latest POSIX make(1) specification.
+
+ 36. Macros which panic on failure in Rust (such as the print!() and println!()
+ macros). Use a function and handle any errors. However, do use the eprintln!()
+ macro for error messages. Handling an error for writing an error message is
+ redundant.
+
+ 37. A -h option for help text. Instead, print usage information when any
+ erroneous option is specified. See the Usage Text section below.
+
+ 38. Lines which exceed 80 columns in width when using four-column indentation
+ steps. This helps contributors with smaller screens, those using side-by-side
+ editor windows or panes, and those who have no text wrapping in their editor or
+ terminal.
+
+
+Usage Text
+==========
+
+This section is adapted from the NetBSD style guide [2].
+
+When programs are invoked incorrectly and in the synopsis of manual pages, uasge
+text should be provided to the user. The following is the format used by this
+project for this purpose:
+
+All optional arguments are to be placed in square brackets (U+005B, U+005D).
+Mutually exclusive arguments can be separated by a vertical line (U+007C).
+Groups of arguments should be specified in alphabetical order in most cases. The
+order of arguments and an example of these rules follows:
+
+ 0. Options with no option arguments.
+ 1. Options with option arguments. Arguments should be specified inside the same
+ square brackets as the options.
+ 3. Non-option arguments.
+
+	"usage: f [-aDde] [-b b_arg] [-m m_arg] req1 req2 [opt1 [opt2]]\n"
+	"usage: f [-a | -b] [-c [-de] [-n number]]\n"
 
-If committing a new utility, please include tests and documentation (see
-tests/ and docs/) for the new tool.
 
 Committing
 ==========
@@ -117,6 +347,10 @@ Committing
 When contributing to Bonsai, please sign your commit with a PGP key and create
 the commit with an identity which can be easily contacted.
 
+If committing a new utility, please include tests and documentation (see
+tests/ and docs/) for the new tool.
+
+
 Format commit messages following these guidelines:
 
 $ git commit -m 'tool(1): add feature x'
@@ -147,9 +381,16 @@ Commit messages should be written in the present tense.
 References
 ==========
 
-[0] <http://cvsweb.netbsd.org/bsdweb.cgi/~checkout~/src/share/misc/style>
+[0] <https://web.eecs.umich.edu/~imarkov/10rules.pdf>
+[1] <http://sekrit.de/webdocs/c/beginners-guide-away-from-scanf.html>
+[2] <http://cvsweb.netbsd.org/bsdweb.cgi/~checkout~/src/share/misc/style>
 
 
 --
-This work © 2023–2024 by Emma Tebibyte is licensed under CC BY-SA 4.0. To view a
-copy of this license, visit <http://creativecommons.org/licenses/by-sa/4.0/>
+
+Copyright © 2023–2024 Emma Tebibyte <emma@tebibyte.media>
+Copyright © 2024 DTB <trinity@trinity.moe>
+Copyright © Wikipedia contributors
+
+This work is licensed under CC BY-SA 4.0. To view a copy of this license, visit
+<http://creativecommons.org/licenses/by-sa/4.0/>.

README

@@ -18,7 +18,8 @@ anywhere. Other utility sets aim to provide a number of fully-featured
 programs to be used individually, Harakit utilities are meant to be easily
 composable and work together in pipelines.
 
-See docs/ for more on the specific utilities currently implemented.
+See docs/ for more on the specific utilities currently implemented and see
+CONTRIBUTING for guidelines for contributions.
 
 
 Building

STYLE

@@ -1,254 +0,0 @@
-“Everyone knows that debugging is twice as hard as writing a program in the
-first place. So if you’re as clever as you can be when you write it, how
-will you ever debug it?”
-	– Brian Kernighan, The Elements of Programming Style
-
-
-The following guidelines are conducive to clear and readable code that is
-consistent with the style of the rest of the Bonsai Computer System.
-
-
-Use
-===
-
- 0. A single line for control flow statements short enough to be easily
- understood at a glance:
-
-	if !(argc < 0) { usage(program_name); }
-
- This applies to C switch statements and cases and Rust match statements, as
- well:
-
-	switch (value) { /* aligning stuff to make it easier to read is fine */
-		case possibility: variable = foo;  break;
-		default:          variable = NULL; break;
-	}
-
- 1. Switch cases in C and match arms in Rust should start another level of
- indentation:
-
-	switch (value) {
-		case possibility:
-			statement;
-			break;
-		default:
-			statement;
-			break;
-	}
-
-	match result {
-		Ok(n) => variable = n,
-		Err(e) => error = e,
-	}
-
- 2. Braces in control flow where their inclusion is left optional in C:
-
-	if (condition) { statement; }
-
- 3. Empty lines between different kinds of statements:
-
-	int t;
-
-	assert(io->bufuse > 0);
-	assert(io->bufuse <= io->bs);
-
-	if ((t = write(io->fd, io->buf, io->bufuse)) < 0) {
-		io->error = errno;
-		t = 0;
-	} else if (t > 0) {
-		memmove(io->buf, &(io->buf)[t], (io->bufuse -= t));
-	}
-
-	io->bytes += t;
-	io->prec  += (t > 0 && io->bufuse > 0);
-	io->rec   += (t > 0 && io->bufuse == 0);
-
-	return io;
-
- 4. Compiler options that yield the most useful warnings, such as -Wpedantic in
- a lot of C compilers. Fix the warnings, too [0].
-
- 5. One more level of indentation and one argument per line when a function
- call or statement header is too long to fit on one line:
-
-	let usage = format!(
-		"Usage: {} [-d delimiter] index command [args...]",
-		argv[0],
-	);
-
- 6. One more level of indentation than the keyword that initiated a multi-line
- block.
-
-	if (condition) {
-		statement;
-		statement;
-	}
-
- 7. The return value of all non-void functions, or explicitly ignore them (like
- casting to void in C) [0]:
-
-	if ((a = malloc(sizeof char)) == NULL) {          /* handle this error */
-		(void)fprintf(stderr, "oh noes!");   /* explicitly ignore this one */
-		return EX_OSERR;       /* ...because the program is exiting anyway */
-	}
-
- 8. The smallest possible scope for data [0].
-
- 9. Comments noting all the symbols and macros used from a C header file, next
- to its include macro:
-
-	#include <unistd.h> /* close(2), getopt(3), lseek(2), read(2), write(2),
-	(space-aligned)      * optarg, optind, STDIN_FILENO, STDOUT_FILENO */
-
- 10. Spaces in control flow statements, after the keyword and before the
- opening brace:
-
-	for (i = 2; i < argc; ++i) {
-
-
- 11. In Rust, a trailing comma on all arguments or fields that are on their own
- lines:
-
-	return Err(EvaluationError {
-		message: format!("{}: Invalid token", i),
-		code: EX_DATAERR,
-	})
-
- 12. In Rust, place extern statements after use statements that include standard
- library crates. Group like statements:
-
-	use std::fs::Path;
-
-	extern crate strerror;
-	extern crate sysexits;
-
-	use strerror::StrError;
-	use sysexits::{ EX_OSERR, EX_USAGE };
-
- 13. If text is on the same line as a brace, spaces after an opening brace and
- before a closing one:
-
-	use sysexits::{ EX_DATAERR, EX_IOERR, EX_UNAVAILABLE, EX_USAGE };
-
- 14. Alphabetic sorting, where applicable:
-
-	use std::io::{ BufWriter, Read, Write, stderr, stdin, stdout }
-
- 15. In Rust, use the to_owned() method on string types (str, OsStr, CStr, etc.)
- and the to_string() method on other types.
-
-
-Avoid
-=====
-
- 16. Unbounded loops [0].
-
- 17. Function pointers [0].
-
- 18. Heap memory allocation [0].
-
- 19. Using too much nested logic (within reason).
-
- 20. Too many levels of dereferences [0]:
-
-	/* do not do this */
-	for (size_t i = 0; i < sizeof a / sizeof *a; ++i) {
-		if (a[i].id == MATCH) { a[i].val = 0; }
-	}
-
-	/* do this */
-	for (struct MadeUp *s = &a[0]; *s != NULL; s = &s[1]) {
-		if (s->id == MATCH) { s->val = 0; }
-	}
-
- 21. Using C preprocessor macros; the fewer, the better [0].
-
- 22. The exit(3p) and std::process::exit() functions; returning from the main
- function skips a system call.
-
-
-Do Not Use
-==========
-
- 23. More than the length of one printed page for a function [0].
-
- 24. Recursion, as it’s complex and can unexpectedly overflow the stack [0].
-
- 25. Any functionality not in the POSIX C specification and language features not
- in C99.
-
- 26. Do-while loops, as they’re unique to C and confusing for casual programmers.
-
- 27. Labels and goto statements; use sensible flow control [0].
-
- 28. Pointer arithmetic, as it tends to be confusing and unnecessary; use
- index-reference patterns like &p[1] instead of p + 1. &p[n] is the address at
- p + sizeof p * n, not p + n, like pointer arithmetic suggests.
-
- 29. C struct bitfields in unions, to access certain bits of bigger data types,
- as it’s poorly defined in the C standards; use bit arithmetic.
-
- 30. C trigraphs.
-
- 31. Inclusions in C header files, to prevent multiple file inclusions.
-
- 32. C preprocessor variables to prevent multiple inclusions of the same file,
- such as:
-
-	#ifdef _FILE
-	#define _FILE
-	/* file body */
-	#endif /* ifdef _FILE */
-
- Instead, take the time to ensure other files aren’t including any files twice.
-
- 33. The gets(3p) function from <stdio.h>, as it’s impossible to prevent buffer
- overflows when it's used; use fgets(3p) from <stdio.h>.
-
- 34. The scanf(3p) function from <stdio.h> [1].
-
- 35. Any functionality not described in the latest POSIX make(1) specification.
-
- 36. Macros which panic on failure in Rust (such as the print!() and println!()
- macros). Use a function and handle any errors. However, do use the eprintln!()
- macro for error messages. Handling an error for writing an error message is
- redundant.
-
-
-Usage Text
-==========
-
-This section is adapted from the NetBSD style guide [2].
-
-When programs are invoked incorrectly and in the synopsis of manual pages, uasge
-text should be provided to the user. The following is the format used by this
-project for this purpose:
-
-All optional arguments are to be placed in square brackets (U+005B, U+005D).
-Mutually exclusive arguments can be separated by a vertical line (U+007C).
-Groups of arguments should be specified in alphabetical order in most cases. The
-order of arguments and an example of these rules follows:
-
- 0. Options with no option arguments.
- 1. Options with option arguments. Arguments should be specified inside the same
- square brackets as the options.
- 3. Non-option arguments.
-
-	"usage: f [-aDde] [-b b_arg] [-m m_arg] req1 req2 [opt1 [opt2]]\n"
-	"usage: f [-a | -b] [-c [-de] [-n number]]\n"
-
-
-References
-==========
-
-[0] <https://web.eecs.umich.edu/~imarkov/10rules.pdf>
-[1] <http://sekrit.de/webdocs/c/beginners-guide-away-from-scanf.html>
-[2] <http://cvsweb.netbsd.org/bsdweb.cgi/~checkout~/src/share/misc/style>
-
---
-Copyright © 2024 Emma Tebibyte <emma@tebibyte.media>
-Copyright © 2024 DTB <trinity@trinity.moe>
-Copyright © Wikipedia contributors
-
-This work is licensed under CC BY-SA 4.0. To view a copy of this license, visit
-<http://creativecommons.org/licenses/by-sa/4.0/>.