made dj options no longer alphabetized

COPYING.GPL

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-                    GNU GENERAL PUBLIC LICENSE
-                       Version 3, 29 June 2007
-
- Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
-
-                            Preamble
-
-  The GNU General Public License is a free, copyleft license for
-software and other kinds of works.
-
-  The licenses for most software and other practical works are designed
-to take away your freedom to share and change the works.  By contrast,
-the GNU General Public License is intended to guarantee your freedom to
-share and change all versions of a program--to make sure it remains free
-software for all its users.  We, the Free Software Foundation, use the
-GNU General Public License for most of our software; it applies also to
-any other work released this way by its authors.  You can apply it to
-your programs, too.
-
-  When we speak of free software, we are referring to freedom, not
-price.  Our General Public Licenses are designed to make sure that you
-have the freedom to distribute copies of free software (and charge for
-them if you wish), that you receive source code or can get it if you
-want it, that you can change the software or use pieces of it in new
-free programs, and that you know you can do these things.
-
-  To protect your rights, we need to prevent others from denying you
-these rights or asking you to surrender the rights.  Therefore, you have
-certain responsibilities if you distribute copies of the software, or if
-you modify it: responsibilities to respect the freedom of others.
-
-  For example, if you distribute copies of such a program, whether
-gratis or for a fee, you must pass on to the recipients the same
-freedoms that you received.  You must make sure that they, too, receive
-or can get the source code.  And you must show them these terms so they
-know their rights.
-
-  Developers that use the GNU GPL protect your rights with two steps:
-(1) assert copyright on the software, and (2) offer you this License
-giving you legal permission to copy, distribute and/or modify it.
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-  For the developers' and authors' protection, the GPL clearly explains
-that there is no warranty for this free software.  For both users' and
-authors' sake, the GPL requires that modified versions be marked as
-changed, so that their problems will not be attributed erroneously to
-authors of previous versions.
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-  Some devices are designed to deny users access to install or run
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-  Finally, every program is threatened constantly by software patents.
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-  The precise terms and conditions for copying, distribution and
-modification follow.
-
-                       TERMS AND CONDITIONS
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-  0. Definitions.
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-  "This License" refers to version 3 of the GNU General Public License.
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-  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
-WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
-THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
-GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
-USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
-DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
-PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
-EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
-SUCH DAMAGES.
-
-  17. Interpretation of Sections 15 and 16.
-
-  If the disclaimer of warranty and limitation of liability provided
-above cannot be given local legal effect according to their terms,
-reviewing courts shall apply local law that most closely approximates
-an absolute waiver of all civil liability in connection with the
-Program, unless a warranty or assumption of liability accompanies a
-copy of the Program in return for a fee.
-
-                     END OF TERMS AND CONDITIONS
-
-            How to Apply These Terms to Your New Programs
-
-  If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these terms.
-
-  To do so, attach the following notices to the program.  It is safest
-to attach them to the start of each source file to most effectively
-state the exclusion of warranty; and each file should have at least
-the "copyright" line and a pointer to where the full notice is found.
-
-    <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) <year>  <name of author>
-
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-Also add information on how to contact you by electronic and paper mail.
-
-  If the program does terminal interaction, make it output a short
-notice like this when it starts in an interactive mode:
-
-    <program>  Copyright (C) <year>  <name of author>
-    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
-    This is free software, and you are welcome to redistribute it
-    under certain conditions; type `show c' for details.
-
-The hypothetical commands `show w' and `show c' should show the appropriate
-parts of the General Public License.  Of course, your program's commands
-might be different; for a GUI interface, you would use an "about box".
-
-  You should also get your employer (if you work as a programmer) or school,
-if any, to sign a "copyright disclaimer" for the program, if necessary.
-For more information on this, and how to apply and follow the GNU GPL, see
-<https://www.gnu.org/licenses/>.
-
-  The GNU General Public License does not permit incorporating your program
-into proprietary programs.  If your program is a subroutine library, you
-may consider it more useful to permit linking proprietary applications with
-the library.  If this is what you want to do, use the GNU Lesser General
-Public License instead of this License.  But first, please read
-<https://www.gnu.org/licenses/why-not-lgpl.html>.

COPYING.LESSER

@@ -1,165 +0,0 @@
-                   GNU LESSER GENERAL PUBLIC LICENSE
-                       Version 3, 29 June 2007
-
- Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
-
-
-  This version of the GNU Lesser General Public License incorporates
-the terms and conditions of version 3 of the GNU General Public
-License, supplemented by the additional permissions listed below.
-
-  0. Additional Definitions.
-
-  As used herein, "this License" refers to version 3 of the GNU Lesser
-General Public License, and the "GNU GPL" refers to version 3 of the GNU
-General Public License.
-
-  "The Library" refers to a covered work governed by this License,
-other than an Application or a Combined Work as defined below.
-
-  An "Application" is any work that makes use of an interface provided
-by the Library, but which is not otherwise based on the Library.
-Defining a subclass of a class defined by the Library is deemed a mode
-of using an interface provided by the Library.
-
-  A "Combined Work" is a work produced by combining or linking an
-Application with the Library.  The particular version of the Library
-with which the Combined Work was made is also called the "Linked
-Version".
-
-  The "Minimal Corresponding Source" for a Combined Work means the
-Corresponding Source for the Combined Work, excluding any source code
-for portions of the Combined Work that, considered in isolation, are
-based on the Application, and not on the Linked Version.
-
-  The "Corresponding Application Code" for a Combined Work means the
-object code and/or source code for the Application, including any data
-and utility programs needed for reproducing the Combined Work from the
-Application, but excluding the System Libraries of the Combined Work.
-
-  1. Exception to Section 3 of the GNU GPL.
-
-  You may convey a covered work under sections 3 and 4 of this License
-without being bound by section 3 of the GNU GPL.
-
-  2. Conveying Modified Versions.
-
-  If you modify a copy of the Library, and, in your modifications, a
-facility refers to a function or data to be supplied by an Application
-that uses the facility (other than as an argument passed when the
-facility is invoked), then you may convey a copy of the modified
-version:
-
-   a) under this License, provided that you make a good faith effort to
-   ensure that, in the event an Application does not supply the
-   function or data, the facility still operates, and performs
-   whatever part of its purpose remains meaningful, or
-
-   b) under the GNU GPL, with none of the additional permissions of
-   this License applicable to that copy.
-
-  3. Object Code Incorporating Material from Library Header Files.
-
-  The object code form of an Application may incorporate material from
-a header file that is part of the Library.  You may convey such object
-code under terms of your choice, provided that, if the incorporated
-material is not limited to numerical parameters, data structure
-layouts and accessors, or small macros, inline functions and templates
-(ten or fewer lines in length), you do both of the following:
-
-   a) Give prominent notice with each copy of the object code that the
-   Library is used in it and that the Library and its use are
-   covered by this License.
-
-   b) Accompany the object code with a copy of the GNU GPL and this license
-   document.
-
-  4. Combined Works.
-
-  You may convey a Combined Work under terms of your choice that,
-taken together, effectively do not restrict modification of the
-portions of the Library contained in the Combined Work and reverse
-engineering for debugging such modifications, if you also do each of
-the following:
-
-   a) Give prominent notice with each copy of the Combined Work that
-   the Library is used in it and that the Library and its use are
-   covered by this License.
-
-   b) Accompany the Combined Work with a copy of the GNU GPL and this license
-   document.
-
-   c) For a Combined Work that displays copyright notices during
-   execution, include the copyright notice for the Library among
-   these notices, as well as a reference directing the user to the
-   copies of the GNU GPL and this license document.
-
-   d) Do one of the following:
-
-       0) Convey the Minimal Corresponding Source under the terms of this
-       License, and the Corresponding Application Code in a form
-       suitable for, and under terms that permit, the user to
-       recombine or relink the Application with a modified version of
-       the Linked Version to produce a modified Combined Work, in the
-       manner specified by section 6 of the GNU GPL for conveying
-       Corresponding Source.
-
-       1) Use a suitable shared library mechanism for linking with the
-       Library.  A suitable mechanism is one that (a) uses at run time
-       a copy of the Library already present on the user's computer
-       system, and (b) will operate properly with a modified version
-       of the Library that is interface-compatible with the Linked
-       Version.
-
-   e) Provide Installation Information, but only if you would otherwise
-   be required to provide such information under section 6 of the
-   GNU GPL, and only to the extent that such information is
-   necessary to install and execute a modified version of the
-   Combined Work produced by recombining or relinking the
-   Application with a modified version of the Linked Version. (If
-   you use option 4d0, the Installation Information must accompany
-   the Minimal Corresponding Source and Corresponding Application
-   Code. If you use option 4d1, you must provide the Installation
-   Information in the manner specified by section 6 of the GNU GPL
-   for conveying Corresponding Source.)
-
-  5. Combined Libraries.
-
-  You may place library facilities that are a work based on the
-Library side by side in a single library together with other library
-facilities that are not Applications and are not covered by this
-License, and convey such a combined library under terms of your
-choice, if you do both of the following:
-
-   a) Accompany the combined library with a copy of the same work based
-   on the Library, uncombined with any other library facilities,
-   conveyed under the terms of this License.
-
-   b) Give prominent notice with the combined library that part of it
-   is a work based on the Library, and explaining where to find the
-   accompanying uncombined form of the same work.
-
-  6. Revised Versions of the GNU Lesser General Public License.
-
-  The Free Software Foundation may publish revised and/or new versions
-of the GNU Lesser General Public License from time to time. Such new
-versions will be similar in spirit to the present version, but may
-differ in detail to address new problems or concerns.
-
-  Each version is given a distinguishing version number. If the
-Library as you received it specifies that a certain numbered version
-of the GNU Lesser General Public License "or any later version"
-applies to it, you have the option of following the terms and
-conditions either of that published version or of any later version
-published by the Free Software Foundation. If the Library as you
-received it does not specify a version number of the GNU Lesser
-General Public License, you may choose any version of the GNU Lesser
-General Public License ever published by the Free Software Foundation.
-
-  If the Library as you received it specifies that a proxy can decide
-whether future versions of the GNU Lesser General Public License shall
-apply, that proxy's public statement of acceptance of any version is
-permanent authorization for you to choose that version for the
-Library.

Makefile

@@ -1,7 +1,6 @@
 # Copyright (c) 2023–2024 Emma Tebibyte <emma@tebibyte.media>
 # Copyright (c) 2023–2024 DTB <trinity@trinity.moe>
 # Copyright (c) 2023 Sasha Koshka <sashakoshka@tebibyte.media>
-# Copyright (c) 2024 Aaditya Aryal <aryalaadi123@gmail.com>
 # SPDX-License-Identifier: FSFAP
 #
 # Copying and distribution of this file, with or without modification, are
@@ -9,26 +8,16 @@
 # notice are preserved.  This file is offered as-is, without any warranty.
 
 .POSIX:
-
-# if using BSD make(1), remove these pragmas because they break it
 .PRAGMA: posix_202x # future POSIX standard support à la pdpmake(1)
 .PRAGMA: command_comment # breaks without this?
 
-DESTDIR ?= dist
-PREFIX ?= /usr/local
+PREFIX=/usr/local
 
-SYSEXITS != printf '\043include <sysexits.h>\n' | cpp -M - | sed 's/ /\n/g' \
-	| sed -n 's/sysexits\.h//p' || printf 'include\n'
-
-CC ?= cc
-RUSTC ?= rustc
-RUSTLIBS = --extern getopt=build/o/libgetopt.rlib \
-	--extern sysexits=build/o/libsysexits.rlib \
-	--extern strerror=build/o/libstrerror.rlib
-CFLAGS += -I$(SYSEXITS)
+CC=cc
+RUSTC=rustc
 
 .PHONY: all
-all: dj false fop hru intcmp mm npc rpn scrut str strcmp swab true
+all: dj false fop hru intcmp mm rpn scrut str strcmp swab true
 
 build:
 	# keep build/include until bindgen(1) has stdin support
@@ -37,39 +26,36 @@ build:
 
 .PHONY: clean
 clean:
-	rm -rf build dist
+	rm -rf build/ dist/
 
 dist: all
-	mkdir -p $(DESTDIR)/$(PREFIX)/bin $(DESTDIR)/$(PREFIX)/share/man/man1
-	cp build/bin/* $(DESTDIR)/$(PREFIX)/bin
-	cp docs/*.1 $(DESTDIR)/$(PREFIX)/share/man/man1
+	mkdir -p dist/bin dist/share/man/man1
+	cp build/bin/* dist/bin/
+	cp docs/*.1 dist/share/man/man1/
 
 .PHONY: install
 install: dist
-	cp -r $(DESTDIR)/* /
+	mkdir -p $(PREFIX)
+	cp -r dist/* $(PREFIX)/
 
 .PHONY: test
 test: build
 	tests/posix-compat.sh
+	$(RUSTC) --test src/getopt-rs/lib.rs -o build/test/getopt
 
-.PHONY: rustlibs
-rustlibs: build/o/libsysexits.rlib build/o/libgetopt.rlib \
-	build/o/libstrerror.rlib
-
-build/o/libgetopt.rlib: build src/getopt.rs
-	$(RUSTC) $(RUSTFLAGS) --crate-type=lib --crate-name=getopt \
-		-o $@ src/getopt.rs
-
-build/o/libstrerror.rlib: build src/strerror.rs
-	$(RUSTC) $(RUSTFLAGS) --crate-type=lib -o $@ \
-		src/strerror.rs
-
-build/o/libsysexits.rlib: build $(SYSEXITS)sysexits.h
+build/o/libsysexits.rlib: build
 	# bandage solution until bindgen(1) gets stdin support
-	printf '#define EXIT_FAILURE 1\n' | cat - $(SYSEXITS)sysexits.h \
+	printf '#define EXIT_FAILURE 1\n' | cat - include/sysexits.h \
 		> build/include/sysexits.h 
 	bindgen --default-macro-constant-type signed --use-core --formatter=none \
-		build/include/sysexits.h | $(RUSTC) $(RUSTFLAGS) --crate-type lib -o $@ -
+		"$$(printf '#include <sysexits.h>\n' \
+			| cpp -M -idirafter "build/include" - \
+			| sed 's/ /\n/g' | grep sysexits.h)" \
+		| $(RUSTC) $(RUSTFLAGS) --crate-type lib -o build/o/libsysexits.rlib -
+
+build/o/libgetopt.rlib: src/getopt-rs/lib.rs
+	$(RUSTC) $(RUSTFLAGS) --crate-type=lib --crate-name=getopt \
+		-o build/o/libgetopt.rlib src/getopt-rs/lib.rs
 
 .PHONY: dj
 dj: build/bin/dj
@@ -83,13 +69,17 @@ build/bin/false: src/false.c build
 
 .PHONY: fop
 fop: build/bin/fop
-build/bin/fop: src/fop.rs build rustlibs
-	$(RUSTC) $(RUSTFLAGS) $(RUSTLIBS) -o $@ src/fop.rs
+build/bin/fop: src/fop.rs build build/o/libgetopt.rlib build/o/libsysexits.rlib
+	$(RUSTC) $(RUSTFLAGS) --extern getopt=build/o/libgetopt.rlib \
+		--extern sysexits=build/o/libsysexits.rlib \
+		-o $@ src/fop.rs
 
 .PHONY: hru
 hru: build/bin/hru
-build/bin/hru: src/hru.rs build rustlibs 
-	$(RUSTC) $(RUSTFLAGS) $(RUSTLIBS) -o $@ src/hru.rs
+build/bin/hru: src/hru.rs build build/o/libgetopt.rlib build/o/libsysexits.rlib
+	$(RUSTC) $(RUSTFLAGS) --extern getopt=build/o/libgetopt.rlib \
+		--extern sysexits=build/o/libsysexits.rlib \
+		-o $@ src/hru.rs
 
 .PHONY: intcmp
 intcmp: build/bin/intcmp
@@ -101,16 +91,12 @@ mm: build/bin/mm
 build/bin/mm: src/mm.c build
 	$(CC) $(CFLAGS) -o $@ src/mm.c
 
-
-.PHONY: npc
-npc: build/bin/npc
-build/bin/npc: src/npc.c build
-	$(CC) $(CFLAGAS) -o $@ src/npc.c
-
 .PHONY: rpn
 rpn: build/bin/rpn
-build/bin/rpn: src/rpn.rs build rustlibs
-	$(RUSTC) $(RUSTFLAGS) $(RUSTLIBS) -o $@ src/rpn.rs
+build/bin/rpn: src/rpn.rs build build/o/libsysexits.rlib
+	$(RUSTC) $(RUSTFLAGS) \
+		--extern sysexits=build/o/libsysexits.rlib \
+		-o $@ src/rpn.rs
 
 .PHONY: scrut
 scrut: build/bin/scrut

docs/dj.1

@@ -1,4 +1,5 @@
 .\" Copyright (c) 2024 DTB <trinity@trinity.moe>
+.\" Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
 .\"
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
@@ -44,87 +45,139 @@ dj
 .B output offset
 .R ])
 
-.SH USAGE
+.SH OPTIONS
 
-The
 .B -i
-option takes a path as an argument to open and use in place of standard input.
-The
-.B -o
-option does the same in place of standard output. Dj does not truncate output
-files and instead writes over the bytes in the existing file.
-.PP
-The
+.RS
+Takes a file path as an argument to open and use as an input.
+.RE
+
 .B -b
-option takes a numeric argument as the size in bytes of the input buffer and
-the
-.B -B
-option does the same for the output buffer, the default for both being 1024
-bytes, or one kibibyte (KiB).
-.PP
-The
+.RS
+Takes a numeric argument as the size in bytes of the input buffer, with the
+default being 1024 bytes or one kibibyte (KiB).
+.RE
+
 .B -s
-option takes a numeric argument as the number of bytes to skip into the input
-before starting to read, and the
+.RS
+Takes a numeric argument as the number of bytes to skip into the input
+before starting to read. If the standard input is used, bytes read to this point
+are discarded.
+.RE
+
+.B -o
+.RS
+Takes a file path as an argument to open and use as an output.
+.RE
+
+.B -B
+.RS
+Does the same as
+.B -b
+but for the output buffer.
+.RE
+
 .B -S
-option skips a number of bytes through the output before starting to write from
-the input. If the input is a stream the bytes are read and discarded. If the
-output is a stream, nul characters are printed.
-.PP
-The
+.RS
+Skips a number of bytes through the output before starting to write from
+the input. If the output is a stream, null characters are printed.
+.RE
+
 .B -a
-option takes one argument of one byte in length and pads the input buffer with
-that byte in the event that a read doesn't fill the input buffer, and the
-.B -A
-option takes no arguments and pads with nuls.
-The
+.RS
+Accepts a single literal byte with which input buffer is padded in the event
+of an incomplete read from the input file.
+.RE
+
 .B -c
-option specifies an amount of reads to make, and if 0 (the default) dj will
-continue reading until a partial or empty read.
-.PP
-On a partial or empty read, dj prints a diagnostic message (unless the
-.B -q
-option is specified) and exits (unless the
-.B -n
-option is specified, in which case only two consecutive empty reads will cause
-dj to exit).
-At exit, usage statistics are printed unless the option
-.B -q
-is specified a second time. The
+.RS
+Specifies a number of reads to make. If set to zero (the default), reading will
+continue until a partial or empty read is encountered.
+.RE
+
+.B -A
+.RS
+If the output is a stream, null bytes are printed. This option is equivalent to
+specifying
+.B -a
+with a null byte instead of a character.
+.RE
+
+.B -d
+.RS
+Prints invocation information before program execution as described in the
+DIAGNOSTICS section below. Each invocation increments the debug level of the
+program.
+.RE
+
 .B -H
-option will make these diagnostics human-readable.
+.RS
+Prints diagnostics messages in a human-readable manner as described in the
+DIAGNOSTICS section below.
+.RE
+
+.B -n
+.RS
+Retries failed reads once more before exiting.
+.RE
+
+.B -q
+.RS
+Suppresses error messages which print when a read or write is partial or
+empty. Each invocation decrements the debug level of the program.
+.RE
+
+.SH STANDARD INPUT
+
+The standard input shall be used as an input if no inputs are specified one or
+more of the input files is “-”.
 
 .SH DIAGNOSTICS
 
-The
-.B -d
-option prints all information, user-specified or otherwise, before program
-execution.
-.PP
-When dj exits, by default statistics are printed for input and output to
-standard error in the following format:
-.PP
+On a partial or empty read, a diagnostic message is printed (unless the
+.B -q
+option is specified) and the program exits (unless the
+.B -n
+option is specified.
+
+By default statistics are printed for input and output to the standard error in
+the following format:
+
+.RS
 .R {records read} {ASCII unit separator} {partial records read}
 .R {ASCII record separator} {records written} {ASCII unit separator}
 .R {partial records written} {ASCII group separator} {bytes read}
 .R {ASCII record separator} {bytes written} {ASCII file separator}
-.PP
-If the
+.RE
+
+This format for diagnostic output is designed to be machine-parseable for
+convenience. For a more human-readable format, the
 .B -H
-option is specified dj instead uses this following format:
-.PP
+option may be specified. In this event, the following format is used instead:
+
+.RS
 .R {records read} '+' {partial records read} '>' {records written}
 .R '+' {partial records written} ';' {bytes read} '>' {bytes written}
 .R {ASCII line feed}
-.PP
-The
-.B -q
-option suppresses error messages which print when a read or write is partial or
-empty and when used twice suppresses diagnostic output entirely.
-.PP
-In non-recoverable errors that don't pertain to dj's read-write cycle, a
-diagnostic message is printed and dj exits with the appropriate sysexits(3)
-status.
+.RE
+
+If the
+.B -d
+option is specified, debug output will be printed at the beginning of execution.
+This debug information contains information regarding how the program was
+invoked. The following example is the result of running the program with
+.B -d
+as the only argument:
+
+.RS
+.R argv0=dj
+.R in=<stdin>      ibs=1024        skip=0  align=ff       count=0
+.R out=<stdout>    obs=1024        seek=0  debug= 3       noerror=0
+.RE
+
+In non-recoverable errors that don’t pertain to the read-write cycle, a
+diagnostic message is printed and the program exits with the appropriate
+sysexits.h(3) status.
 
 .SH BUGS
 
@@ -136,25 +189,29 @@ expected (the product of the count multiplied by the input block size). If the
 or
 .B -A
 options are used this could make data written nonsensical.
-.PP
+
 Many lowercase options have capitalized variants and vice-versa which can be
 confusing. Capitalized options tend to affect output or are more intense
 versions of lowercase options.
 
+.SH CAVEATS
+
+Existing files are not truncated on ouput and are instead overwritten.
+
 .SH RATIONALE
 
-Dj was modeled after the dd utility specified in POSIX but adds additional
-features: typical option formatting, allowing seeks to be specified in bytes
+This program was based on the dd(1p) utility as specified in POSIX. While
+character conversion may have been the original intent of dd(1p), it is
+irrelevant to its modern use. Because of this, it eschews character conversion
+and adds typical option formatting, allowing seeks to be specified in bytes
 rather than in blocks, allowing arbitrary bytes as padding, and printing in a
-format that's easy to parse for machines. It also neglects character
-conversion, which may be dd's original intent but is irrelevant to its modern
-use.
+format that’s easy to parse for machines.
 
 .SH COPYRIGHT
 
-Copyright (C) 2023 DTB. License AGPLv3+: GNU AGPL version 3 or later
+Copyright © 2023 DTB. License AGPLv3+: GNU AGPL version 3 or later
 <https://gnu.org/licenses/agpl.html>.
 
 .SH SEE ALSO
 
-dd(1)
+dd(1p)

docs/false.1

@@ -1,5 +1,5 @@
 .\" Copyright (c) 2022, 2024 DTB <trinity@trinity.moe>
-.\" Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+.\" Copyright (c) 2023–2024 Emma Tebibyte <emma@tebibyte.media>
 .\"
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
@@ -12,14 +12,13 @@ false \(en do nothing, unsuccessfully
 
 .SH DESCRIPTION
 
-False does nothing regardless of operands or standard input.
-False will always return an exit code of 1.
+Do nothing regardless of operands or standard input.
+An exit code of 1 will always be returned.
 
 .SH RATIONALE
 
-False exists for the construction of control flow and loops based on a failure.
-
-False functions as described in POSIX.1-2017.
+In POSIX.1-2017, false(1p) exists for the construction of control flow and loops
+based on a failure. This implementation functions as described in that standard.
 
 .SH AUTHOR
 

docs/fop.1

@@ -0,0 +1,60 @@
+.\" Copyright (c) 2024 DTB <trinity@trinity.moe>
+.\" Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
+.\"
+.\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
+.\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
+
+.TH fop 1
+
+.SH NAME
+
+fop \(en field operator
+
+.SH SYNOPSIS
+
+fop
+.RB ( -d )
+.RB [ delimiter ]
+.RB index 
+.RB program...
+
+.SH DESCRIPTION
+
+Performs operations on specified fields in input data.
+
+.SH OPTIONS
+
+.B -d
+.RS
+Sets a delimiter by which the input data will be split into fields. The default
+is an ASCII record separator (␞).
+.RE
+
+.SH STANDARD INPUT
+
+Data will be read from the standard input.
+
+.SH CAVEATS
+
+Field indices are zero-indexed, which may be unexpected behavior for some users.
+
+.SH RATIONALE
+
+With the assumption that tools will output data separated with ASCII field
+separators, there is 
+
+The idea for this utility originated in the fact that GNU ls(1) utility contains
+a
+.B -h
+option which enables human-readable units in file size outputs. This
+functionality was broken out into hru(1), but there was no easy way to modify
+the field in the ouput of ls(1p) without a new tool.
+
+.SH COPYRIGHT
+
+Copyright © 2024 Emma Tebibyte. License AGPLv3+: GNU AGPL version 3 or later
+<https://gnu.org/licenses/agpl.html>.
+
+.SH SEE ALSO
+
+sed(1p)

docs/hru.1

@@ -3,7 +3,7 @@
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
 
-.TH rpn 1
+.TH hru 1
 
 .SH NAME
 
@@ -15,18 +15,20 @@ hru
 
 .SH DESCRIPTION
 
-Hru reads byte counts in the form of whole numbers from the standard input and
-writes to the standard output the same number converted one of the units of data
-defined by the International System of Units.
+Convert counts to higher units.
+
+The program will read byte counts in the form of whole numbers from the standard
+input and write to the standard output the same number converted to a higher 
+unit of data as defined by the International System of Units.
 
 The program will convert the byte count to the highest unit possible where the
 value is greater than one.
 
 .SH DIAGNOSTICS
 
-If encountering non-integer characters in the standard input, hru will exit with
-the appropriate error code as defined by sysexits.h(3) and print an error
-message.
+If encountering non-integer characters in the standard input, the program will
+exit with the appropriate error code as defined by sysexits.h(3) and print an
+error message.
 
 .SH RATIONALE
 
@@ -39,9 +41,9 @@ program.
 
 .SH STANDARDS
 
-Hru follows the standard unit prefixes as specified by the Bureau International
-des Poids et Mesures (BIPM) in the ninth edition of The International System of
-Units (SI).
+The standard unit prefixes as specified by the Bureau International des Poids
+et Mesures (BIPM) in the ninth edition of The International System of Units
+(SI) are utilized for the ouput of conversions.
 
 .SH AUTHOR
 

docs/intcmp.1

@@ -1,5 +1,5 @@
 .\" Copyright (c) 2023–2024 DTB <trinity@trinity.moe>
-.\" Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+.\" Copyright (c) 2023–2024 Emma Tebibyte <emma@tebibyte.media>
 .\"
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
@@ -13,45 +13,59 @@ intcmp \(en compare integers
 .SH SYNOPSIS
 
 intcmp
-.RB ( -eghl )
+.RB ( -egl )
 .RB [ integer ]
 .RB [ integer... ]
 
 .SH DESCRIPTION
 
-Intcmp compares integers.
+Compare integers to each other.
 
 .SH USAGE
 
-The -e option permits given integers to be equal to each other. If combined
-with -g or -l, only adjacent integers in the argument sequence can be equal.
-.PP
-The -g option permits a given integer to be greater than the following integer.
-.PP
-The -l option permits a given integer to be less than the following integer.
-.PP
+.B -e
+.RS
+Permits given integers to be equal to each other.
+.RE
+
+.B -g
+.RS
+Permits a given integer to be greater than the following integer.
+.RE
+
+.B -l
+.RS
+Permits a given integer to be less than the following integer.
+.RE
+
+.SH EXAMPLES
+
 It may help to think of the -e, -g, and -l options as equivalent to the
 infix algebraic “=”, “>”, and “<” operators respectively, with each option
-putting its symbol between every given integer. For example,
+putting its symbol between every given integer. The following example is
+equivalent to evaluating “1 < 2 < 3”:
+
+.RS
 .R intcmp -l 1 2 3
-is equivalent to evaluating "1 < 2 < 3".
+.RE
 
 .SH DIAGNOSTICS
 
-Intcmp exits 0 for a valid expression and 1 for an invalid expression.
-.PP
-Intcmp prints a debug message and exits with the appropriate sysexits(3) error
-code in the event of an error.
+The program will exit with a status code of 0 for a valid expression and with a
+code of 1 for an invalid expression.
+
+In the event of an error, a debug message will be printed and the program will
+exit with the appropriate sysexits.h(3) error code.
 
 .SH BUGS
 
 There are multiple ways to express compound comparisons; “less than or equal
 to” can be -le or -el, for example.
-.PP
+
 The inequality comparison is -gl or -lg for “less than or greater than”; this
 is elegant but unintuitive.
-.PP
--egl, "equal to or less than or greater than", exits 0 no matter what for valid
+
+-egl, “equal to or less than or greater than”, exits 0 no matter what for valid
 program usage and may be abused to function as an integer validator.
 Use str(1) instead.
 
@@ -61,7 +75,7 @@ The traditional tool for integer comparisons in POSIX and other Unix shells has
 been test(1). This tool also handles string comparisons and file scrutiny.
 These parts of its functionality have been broken out into multiple utilities.
 
-Strcmp’s functionality may be performed on a POSIX-compliant system with
+This program’s functionality may be performed on a POSIX-compliant system with
 test(1p).
 
 .SH AUTHOR

docs/mm.1

@@ -20,51 +20,63 @@ mm
 
 .SH DESCRIPTION
 
-Mm catenates input files and writes them to the start of each output file.
+Catenate input files and write them to the start of each output file or stream.
 
 .SH OPTIONS
 
-Mm, upon receiving the
 .B -a
-option, will open subsequent outputs for appending rather than updating.
-.PP
-The
-.B -i
-option opens a path as an input. Without any inputs specified mm will use
-standard input. Standard input itself can be specified by giving the path '-'.
-.PP
-The
-.B -o
-option opens a path as an output. Without any outputs specified mm will use
-standard output. Standard output itself can be specified by giving the
-path '-'. Standard error itself can be specified with the
+.RS
+Opens subsequent outputs for appending rather than updating.
+.RE
+
 .B -e
-option.
-.PP
-The
+.RS
+Use the standard error as an output.
+.RE
+
+.B -i
+.RS
+Opens a path as an input. Without any inputs specified mm will use the
+standard input. The standard input shall be used as an input if one or more of
+the input files is “-”.
+.RE
+
+.B -o
+.RS
+Opens a path as an output. Without any outputs specified mm will use the
+standard output. The standard output shall be used as an output if one or more
+of the output files is “-”.
+
+.RE
+
 .B -u
-option ensures neither input or output will be buffered.
-.PP
-The
+.RS
+Ensures neither input or output will be buffered.
+.RE
+
 .B -n
-option tells mm to ignore SIGINT signals.
+.RS
+Causes SIGINT signals to be ignored.
+.RE
 
 .SH DIAGNOSTICS
 
 If an output can no longer be written mm prints a diagnostic message, ceases
 writing to that particular output, and if there are more outputs specified,
 continues, eventually exiting unsuccessfully.
-.PP
-On error mm prints a diagnostic message and exits with the appropriate
-sysexits.h(3) status.
 
-.SH BUGS
+When an error is encountered, diagnostic message is printed and the program
+exits with the appropriate sysexits.h(3) status.
 
-Mm does not truncate existing files, which may lead to unexpected results.
+.SH CAVEATS
+
+Existing files are not truncated on ouput and are instead overwritten.
 
 .SH RATIONALE
 
-Mm was modeled after the cat and tee utilities specified in POSIX.
+The cat(1p) and tee(1p) programs specified in POSIX together provide similar
+functionality. The separation of the two sets of functionality into separate
+APIs seemed unncessary.
 
 .SH COPYRIGHT
 

docs/npc.1

@@ -1,5 +1,5 @@
 .\" Copyright (c) 2023–2024 DTB <trinity@trinity.moe>
-.\" Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+.\" Copyright (c) 2023–2024 Emma Tebibyte <emma@tebibyte.media>
 .\"
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
@@ -13,43 +13,50 @@ npc \(en show non-printing characters
 .SH SYNOPSIS
 
 npc
-.RB ( -eht )
+.RB ( -et )
 
 .SH DESCRIPTION
 
-Npc reads from standard input and writes to standard output, replacing non-
-printing characters with printable equivalents. Control characters print as a
-carat ('^') followed by the character '@' through '_' corresponding to the
-character replaced (e.g. control-X becomes "^X"). The delete character (0x7F)
-becomes "^?". Characters with the high bit set (>127) are printed as "M-"
+Print normally non-printing characters.
+
+The program reads from standard input and writes to standard output, replacing
+non-printing characters with printable equivalents. Control characters print as
+a carat ('^') followed by the character '@' through '_' corresponding to the
+character replaced (e.g. control-X becomes '^X'). The delete character (0x7F)
+becomes '^?'. Characters with the high bit set (>127) are printed as 'M-'
 followed by the graphical representation for the same character without the
 high bit set.
-.PP
-The
+
+.SH USAGE
+
 .B -e
-option prints a currency sign ('$') before each line ending.
-.PP
-The
+.RS
+Prints a currency sign ('$') before each line ending.
+.RE
+
 .B -t
-option prints tab characters as "^I" rather than a literal horizontal tab.
+.RS
+Prints tab characters as '^I' rather than a literal horizontal tab.
+.RE
 
 .SH DIAGNOSTICS
 
-Npc prints a debug message and exits with the appropriate sysexits(3) error
-code in the event of an error, otherwise it exits successfully.
+In the event of an error, a debug message will be printed and the program will
+exit with the appropriate sysexits.h(3) error code.
 
 .SH BUGS
 
-Npc operates in single-byte chunks regardless of intended encoding.
+The program operates in single-byte chunks regardless of intended encoding.
 
 .SH RATIONALE
 
 POSIX currently lacks a way to display non-printing characters in the terminal
-using a standard tool. A popular extension to cat(1p), the -v option, is the
-bandage solution GNU and other software suites use.
+using a standard tool. A popular extension to cat(1p), the
+.B -v
+option, is the bandage solution GNU and other software suites use.
 
-This functionality should be a separate tool because its usefulness extends
-beyond that of cat(1p).
+This functionality is a separate tool because its usefulness extends beyond that
+of cat(1p).
 
 .SH AUTHOR
 

docs/rpn.1

@@ -17,10 +17,13 @@ rpn
 
 .SH DESCRIPTION
 
-Rpn evaluates reverse polish notation expressions either read from the standard
-input or parsed from provided arguments. See the STANDARD INPUT section.
+Evaluate reverse polish notation.
 
-Upon evaluation, rpn will print the resulting number on the stack to the
+The program evaluates reverse polish notation expressions either read from the
+standard input or parsed from provided arguments. See the STANDARD INPUT
+section.
+
+Upon evaluation, the program will print the resulting number on the stack to the
 standard output. Any further specified numbers will be placed at the end of the
 stack.
 
@@ -28,14 +31,16 @@ For information on for reverse polish notation syntax, see rpn(7).
 
 .SH STANDARD INPUT
 
-If arguments are passed to rpn, it interprets them as an expression to be
-evaluated. Otherwise, it reads whitespace-delimited numbers and operations from
-the standard input.
+If arguments are passed , they are interpreted as an expression to be evaluated.
+Otherwise, it reads whitespace-delimited numbers and operations from the
+standard input.
 
 .SH DIAGNOSTICS
 
-If encountering a syntax error, rpn will exit with the appropriate error code
-as defined by sysexits.h(3) and print an error message.
+In the event of a syntax error, the program will print an
+
+In the event of an error, a debug message will be printed and the program will
+exit with the appropriate sysexits.h(3) error code.
 
 .SH CAVEATS
 
@@ -44,7 +49,7 @@ with the IEEE Standard for Floating Point Arithmetic (IEEE 754), floating-point
 arithmetic has rounding errors. This is somewhat curbed by using the
 machine epsilon as provided by the Rust standard library to which to round
 numbers. Because of this, variation is expected in the number of decimal places 
-rpn can handle based on the platform and hardware of any given machine.
+the program can handle based on the platform and hardware of any given machine.
 
 .SH RATIONALE
 

docs/scrut.1

@@ -1,4 +1,5 @@
 .\" Copyright (c) 2024 DTB <trinity@trinity.moe>
+.\" Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
 .\"
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
@@ -17,62 +18,92 @@ scrut
 
 .SH DESCRIPTION
 
-Scrut determines if given files comply with the opted requirements.
+Determine if files comply with requirements.
 
 .SH OPTIONS
 
-.B -b
-requires the given files to exist and be block special files.
-.PP
-.B -c
-requires the given files to exist and be character special files.
-.PP
-.B -d
-requires the given files to exist and be directories.
-.PP
-.B -e
-requires the given files to exist, and is redundant to any other option.
-.PP
-.B -e
-requires the given files to exist and be regular files.
-.PP
-.B -g
-requires the given files to exist and have their set group ID flags set.
-.PP
-.B -k
-requires the given files to exist and have their sticky bit set.
-.PP
-.B -p
-requires the given files to exist and be named pipes.
-.PP
-.B -r
-requires the given files to exist and be readable.
-.PP
-.B -u
-requires the given files to exist and have their set user ID flags set.
-.PP
-.B -w
-requires the given files to exist and be writable.
-.PP
-.B -x
-requires the given files to exist and be executable.
-.PP
 .B -L
-requires the given files to exist and be symbolic links.
-.PP
+.RS
+Requires the given files to exist and be symbolic links.
+.RE
+
 .B -S
-requires the given files to exist and be sockets.
+.RS
+Requires the given files to exist and be sockets.
+.RE
+
+.B -b
+.RS
+Requires the given files to exist and be block special files.
+.RE
+
+.B -c
+.RS
+Requires the given files to exist and be character special files.
+.RE
+
+.B -d
+.RS
+Requires the given files to exist and be directories.
+.RE
+
+.B -e
+.RS
+Requires the given files to exist, and is redundant to any other option.
+.RE
+
+.B -e
+.RS
+Requires the given files to exist and be regular files.
+.RE
+
+.B -g
+.RS
+Requires the given files to exist and have their set group ID flags set.
+.RE
+
+.B -k
+.RS
+Requires the given files to exist and have their sticky bit set.
+.RE
+
+.B -p
+.RS
+Requires the given files to exist and be named pipes.
+.RE
+
+.B -r
+.RS
+Requires the given files to exist and be readable.
+.RE
+
+.B -u
+.RS
+Requires the given files to exist and have their set user ID flags set.
+.RE
+
+.B -w
+.RS
+Requires the given files to exist and be writable.
+.RE
+
+.B -x
+.RS
+Requires the given files to exist and be executable.
+.RE
 
 .SH EXIT STATUS
 
-Scrut prints a debug message and exits unsuccessfully with the appropriate
-sysexits.h(3) error code if invoked incorrectly. Scrut exits successfully if
-the given files comply with their requirements and unsuccessfully otherwise.
+If the given files comply with the specified requirements, the program will exit
+successfully. If not, it exits unsuccessfully.
+
+When invoked incorrectly, a debug message will be printed and the program will
+exit with the appropriate sysexits.h(3) error code.
 
 .SH STANDARDS
 
-Scrut is nearly compatible with POSIX's test utility though it is narrower in
-scope. Notably, the
+The test(1p) utility contains functionality that was broken out into separate
+programs. Thus, the scope of this program is narrower than it. Notably, the
 .B -h
 option is now invalid and therefore shows usage information instead of being an
 alias to the modern

docs/str.1

@@ -1,5 +1,5 @@
 .\" Copyright (c) 2023–2024 DTB <trinity@trinity.moe>
-.\" Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+.\" Copyright (c) 2023–2024 Emma Tebibyte <emma@tebibyte.media>
 .\"
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
@@ -18,30 +18,27 @@ str
 
 .SH DESCRIPTION
 
-Str tests each character in an arbitrary quantity of string arguments against
-the function of the same name within ctype(3).
+Test string arguments.
+
+The tests in this program are equivalent to the functions with the same names in
+ctype.h(0p) and are the methods by which string arguments are tested.
 
 .SH DIAGNOSTICS
 
-Str exits successfully if all tests pass and unsuccessfully if a test failed.
-.PP
-Str will exit unsuccessfully if a string is empty, as none of its contents
-passed the test.
-.PP
-Str will print a message to standard error and exit unsuccessfully if used
-improperly.
+If all tests pass, the program will exit with an exit code of 0. If any of the
+tests fail, the program will exit unsuccessfully with an error code of 1.
 
-.SH DEPRECATED FEATURES
+An empty string will cause an unsuccessful exit as none of its contents pass any
+tests.
 
-Str used to have an "isvalue" type as an extension to ctype(3). This was
-removed in favor of using strcmp(1) to compare strings against the empty string
-('').
+When invoked incorrectly, a debug message will be printed and the program will
+exit with the appropriate sysexits.h(3) error code.
 
 .SH BUGS
 
-There's no way of knowing which argument failed the test without re-testing
+There’s no way of knowing which argument failed the test without re-testing
 arguments individually.
-.PP
+
 If a character in a string isn't valid ASCII str will exit unsuccessfully.
 
 .SH AUTHOR

docs/strcmp.1

@@ -1,5 +1,5 @@
 .\" Copyright (c) 2023–2024 DTB <trinity@trinity.moe>
-.\" Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+.\" Copyright (c) 2023–2024 Emma Tebibyte <emma@tebibyte.media>
 .\"
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
@@ -18,26 +18,27 @@ strcmp
 
 .SH DESCRIPTION
 
-Strcmp checks whether the given strings are the same.
-Strcmp exits successfully if the strings are identical. Otherwise, strcmp exits
-with the value 1 if an earlier string has a greater byte value than a later
-string (e.g.
+Check whether string arguments are the same.
+
+.SH DIAGNOSTICS
+
+The program will exit successfully if the strings are identical. Otherwise, it
+exits with the value 1 if an earlier string has a greater byte value than a
+later string (e.g.
 .R strcmp b a
 )
 and 255 if an earlier string has a lesser byte value (e.g.
 .R strcmp a b
 ).
 
-.SH DIAGNOSTICS
-
-Strcmp will print an error message and exit unsuccessfully with a status
-described in sysexits(3) if used incorrectly (given less than two operands).
+When invoked incorrectly, a debug message will be printed and the program will
+exit with the appropriate sysexits.h(3) error code.
 
 .SH UNICODE
 
-Strcmp will exit unsuccessfully if the given strings are not identical;
-Unicode strings may need to be normalized if the intent is to check visual
-similarity and not byte similarity.
+The program will exit unsuccessfully if the given strings are not identical;
+therefore, Unicode strings may need to be normalized if the intent is to check
+visual similarity and not byte similarity.
 
 .SH RATIONALE
 
@@ -45,7 +46,7 @@ The traditional tool for string comparisons in POSIX and other Unix shells has
 been test(1). This tool also handles integer comparisons and file scrutiny.
 These parts of its functionality have been broken out into multiple utilities.
 
-Strcmp’s functionality may be performed on a POSIX-compliant system with
+This program’s functionality may be performed on a POSIX-compliant system with
 test(1p).
 
 .SH AUTHOR

docs/swab.1

@@ -1,4 +1,5 @@
 .\" Copyright (c) 2024 DTB <trinity@trinity.moe>
+.\" Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
 .\"
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
@@ -20,46 +21,51 @@ swab
 
 .SH USAGE
 
-Swab swaps the latter and former halves of a block of bytes.
+Swap the latter and former halves of a block of bytes.
+
+.SH OPTIONS
+
+.B -f
+.RS
+Ignore system call interruptions.
+.RE
+
+.B -w
+.RS
+Configures the word size; that is, the size in bytes of the block size
+on which to operate. By default the word size is 2. The word size must be
+cleanly divisible by 2, otherwise the block of bytes being processed can't be
+halved.
+.RE
 
 .SH EXAMPLES
 
 The following sh(1p) line:
 
+.RS
 .R printf 'hello world!\n' | swab
+.RE
 
 Produces the following output:
 
+.RS
 .R ehll oowlr!d
-
-.SH OPTIONS
-
-The
-.B -f
-option ignores system call interruptions.
-.PP
-The
-.B -w
-option configures the word size; that is, the size in bytes of the block size
-on which to operate. By default the word size is 2. The word size must be
-cleanly divisible by 2, otherwise the block of bytes being processed can't be
-halved.
+.RE
 
 .SH DIAGNOSTICS
 
-If an error is encountered in input, output, or invocation, a diagnostic
-message will be written to standard error and swab will exit with the
-appropriate status from sysexits.h(3).
+In the event of an error, a debug message will be printed and the program will
+exit with the appropriate sysexits.h(3) error code.
 
 .SH RATIONALE
 
-Swab was modeled after the
+This program was modeled and named after the
 .R conv=swab
-functionality specified in the POSIX dd utility but additionally allows the
-word size to be configured.
-.PP
-Swab is useful for fixing the endianness of binary files produced on other
-machines.
+functionality specified in the dd(1p) utility. It additionally allows the word
+size to be configured.
+
+This functionality is useful for fixing the endianness of binary files produced
+on other machines.
 
 .SH COPYRIGHT
 

docs/true.1

@@ -1,5 +1,5 @@
 .\" Copyright (c) 2022, 2024 DTB <trinity@trinity.moe>
-.\" Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+.\" Copyright (c) 2023–2024 Emma Tebibyte <emma@tebibyte.media>
 .\"
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
@@ -12,14 +12,13 @@ true \(en do nothing, successfully
 
 .SH DESCRIPTION
 
-True does nothing regardless of operands or standard input.
-True will always return an exit code of 0.
+Do nothing regardless of operands or standard input.
+An exit code of 0 will always be returned.
 
 .SH RATIONALE
 
-True exists for the construction of control flow and loops based on a success.
-
-True functions as described in POSIX.1-2017.
+In POSIX.1-2017, true(1p) exists for the construction of control flow and loops
+based on a success. This implementation functions as described in that standard.
 
 .SH AUTHOR
 

src/fop.rs

@@ -22,52 +22,40 @@ use std::{
 	process::{ Command, exit, Stdio },
 };
 
-extern crate getopt;
-extern crate strerror;
 extern crate sysexits;
+extern crate getopt;
 
-use getopt::GetOpt;
-use strerror::StrError;
+use getopt::{ Opt, Parser };
 use sysexits::{ EX_DATAERR, EX_IOERR, EX_UNAVAILABLE, EX_USAGE };
 
 fn main() {
 	let argv = args().collect::<Vec<String>>();
 	let mut d = '␞';
-	let usage = format!(
-		"Usage: {} [-d delimiter] index command [args...]",
-		argv[0],
-	);
-	let mut index_arg = 0;
+	let mut arg_parser = Parser::new(&argv, "d:");
 
-	while let Some(opt) = argv.getopt("d:") {
+	while let Some(opt) = arg_parser.next() {
 		match opt {
-			Ok(o) => {
-				/* unwrap because Err(OptError::MissingArg) will be returned if
-				 * o.arg is None */
-				let arg = o.arg.unwrap();
+			Ok(Opt('d', Some(arg))) => {
 				let arg_char = arg.chars().collect::<Vec<char>>();
 				if arg_char.len() > 1 {
 					eprintln!("{}: {}: Not a character.", argv[0], arg);
 					exit(EX_USAGE);
 				} else { d = arg_char[0]; }
-				index_arg = o.ind as usize;
 			},
-			Err(_) => {
-				eprintln!("{}", usage);
-				exit(EX_USAGE);
-			}
+			_ => {},
 		};
 	}
 
-	let command_arg = index_arg as usize + 1;
+	let index_arg = arg_parser.index();
+	let command_arg = arg_parser.index() + 1;
 
 	argv.get(command_arg).unwrap_or_else(|| {
-		eprintln!("{}", usage);
+		eprintln!("Usage: {} [-d delimiter] index command [args...]", argv[0]);
 		exit(EX_USAGE);
 	});
 
 	let index = argv[index_arg].parse::<usize>().unwrap_or_else(|e| {
-		eprintln!("{}: {}: {}", argv[0], argv[1], e);
+		eprintln!("{}: {}: {}.", argv[0], argv[1], e);
 		exit(EX_DATAERR);
 	});
 
@@ -87,13 +75,13 @@ fn main() {
 		.stdout(Stdio::piped())
 		.spawn()
 		.unwrap_or_else( |e| {
-			eprintln!("{}: {}: {}", argv[0], argv[command_arg], e.strerror());
+			eprintln!("{}: {}: {}.", argv[0], argv[command_arg], e);
 			exit(EX_UNAVAILABLE);
 		});
 
 	let field = fields.get(index).unwrap_or_else(|| {
 		eprintln!(
-			"{}: {}: No such index in input",
+			"{}: {}: No such index in input.",
 			argv[0],
 			index.to_string(),
 		);
@@ -106,7 +94,7 @@ fn main() {
 	}
 
 	let output = spawned.wait_with_output().unwrap_or_else(|e| {
-		eprintln!("{}: {}: {}", argv[0], argv[command_arg], e.strerror());
+		eprintln!("{}: {}: {}.", argv[0], argv[command_arg], e);
 		exit(EX_IOERR);
 	});
 
@@ -115,7 +103,7 @@ fn main() {
 	if replace.pop() != Some(b'\n') { replace = output.stdout; }
 
 	let new_field = String::from_utf8(replace).unwrap_or_else(|e| {
-		eprintln!("{}: {}: {}", argv[0], argv[command_arg], e);
+		eprintln!("{}: {}: {}.", argv[0], argv[command_arg], e);
 		exit(EX_IOERR);
 	});
 
@@ -123,8 +111,8 @@ fn main() {
 
 	stdout().write_all(
 		fields.join(&d.to_string()).as_bytes()
-	).unwrap_or_else(|e| {
-		eprintln!("{}: {}", argv[0], e.strerror());
+	).unwrap_or_else(|e|{
+		eprintln!("{}: {}.", argv[0], e);
 		exit(EX_IOERR);
 	});
 }

src/getopt-rs/error.rs

@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ *
+ * This file incorporates work covered by the following copyright and permission
+ * notice:
+ *     The Clear BSD License
+ *
+ *     Copyright © 2017-2023 David Wildasin
+ *     All rights reserved.
+ *
+ *     Redistribution and use in source and binary forms, with or without
+ *     modification, are permitted (subject to the limitations in the disclaimer
+ *     below) provided that the following conditions are met:
+ *
+ *          * Redistributions of source code must retain the above copyright
+ *          notice, this list of conditions, and the following disclaimer.
+ *
+ *          * Redistributions in binary form must reproduce the above copyright
+ *          notice, this list of conditions, and the following disclaimer in the
+ *          documentation and/or other materials provided with the distribution.
+ *
+ *          * Neither the name of the copyright holder nor the names of its
+ *          contributors may be used to endorse or promote products derived from
+ *          this software without specific prior written permission.
+ *
+ *     NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
+ *     BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
+ *     BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ *     FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *     HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ *     TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ *     PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *     LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *     NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ *     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+use std::{ error, fmt };
+
+use crate::ErrorKind::{ self, * };
+
+/// A basic error type for [`Parser`](struct.Parser.html)
+#[derive(Debug, Eq, PartialEq)]
+pub struct Error {
+    culprit: char,
+    kind: ErrorKind,
+}
+
+impl Error {
+    /// Creates a new error using a known kind and the character that caused the
+	/// issue.
+    pub fn new(kind: ErrorKind, culprit: char) -> Self {
+        Self { culprit, kind }
+    }
+
+    /// Returns the [`ErrorKind`](enum.ErrorKind.html) for this error.
+    pub fn kind(self) -> ErrorKind {
+        self.kind
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self.kind {
+            MissingArgument => write!(
+				f, 
+				"option requires an argument -- {:?}",
+				self.culprit,
+			),
+            UnknownOption => write!(f, "unknown option -- {:?}", self.culprit),
+        }
+    }
+}
+
+impl error::Error for Error {
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        None
+    }
+}

src/getopt-rs/errorkind.rs

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ *
+ * This file incorporates work covered by the following copyright and permission
+ * notice:
+ *     The Clear BSD License
+ *
+ *     Copyright © 2017-2023 David Wildasin
+ *     All rights reserved.
+ *
+ *     Redistribution and use in source and binary forms, with or without
+ *     modification, are permitted (subject to the limitations in the disclaimer
+ *     below) provided that the following conditions are met:
+ *
+ *          * Redistributions of source code must retain the above copyright
+ *          notice, this list of conditions, and the following disclaimer.
+ *
+ *          * Redistributions in binary form must reproduce the above copyright
+ *          notice, this list of conditions, and the following disclaimer in the
+ *          documentation and/or other materials provided with the distribution.
+ *
+ *          * Neither the name of the copyright holder nor the names of its
+ *          contributors may be used to endorse or promote products derived from
+ *          this software without specific prior written permission.
+ *
+ *     NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
+ *     BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
+ *     BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ *     FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *     HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ *     TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ *     PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *     LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *     NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ *     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/// What kinds of errors [`Parser`](struct.Parser.html) can return.
+#[derive(Debug, Eq, PartialEq)]
+pub enum ErrorKind {
+    /// An argument was not found for an option that was expecting one.
+    MissingArgument,
+    /// An unknown option character was encountered.
+    UnknownOption,
+}

src/getopt-rs/lib.rs

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ *
+ * This file incorporates work covered by the following copyright and permission
+ * notice:
+ *     The Clear BSD License
+ *
+ *     Copyright © 2017-2023 David Wildasin
+ *     All rights reserved.
+ *
+ *     Redistribution and use in source and binary forms, with or without
+ *     modification, are permitted (subject to the limitations in the disclaimer
+ *     below) provided that the following conditions are met:
+ *
+ *          * Redistributions of source code must retain the above copyright
+ *          notice, this list of conditions, and the following disclaimer.
+ *
+ *          * Redistributions in binary form must reproduce the above copyright
+ *          notice, this list of conditions, and the following disclaimer in the
+ *          documentation and/or other materials provided with the distribution.
+ *
+ *          * Neither the name of the copyright holder nor the names of its
+ *          contributors may be used to endorse or promote products derived from
+ *          this software without specific prior written permission.
+ *
+ *     NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
+ *     BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
+ *     BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ *     FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *     HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ *     TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ *     PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *     LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *     NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ *     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+//! # getopt
+//!
+//! `getopt` provides a minimal, (essentially) POSIX-compliant option parser.
+
+pub use crate::{
+	error::Error,
+	errorkind::ErrorKind,
+	opt::Opt,
+	parser::Parser,
+	result::Result
+};
+
+mod error;
+mod errorkind;
+mod opt;
+mod parser;
+mod result;
+#[cfg(test)]
+mod tests;

src/getopt-rs/opt.rs

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ *
+ * This file incorporates work covered by the following copyright and permission
+ * notice:
+ *     The Clear BSD License
+ *
+ *     Copyright © 2017-2023 David Wildasin
+ *     All rights reserved.
+ *
+ *     Redistribution and use in source and binary forms, with or without
+ *     modification, are permitted (subject to the limitations in the disclaimer
+ *     below) provided that the following conditions are met:
+ *
+ *          * Redistributions of source code must retain the above copyright
+ *          notice, this list of conditions, and the following disclaimer.
+ *
+ *          * Redistributions in binary form must reproduce the above copyright
+ *          notice, this list of conditions, and the following disclaimer in the
+ *          documentation and/or other materials provided with the distribution.
+ *
+ *          * Neither the name of the copyright holder nor the names of its
+ *          contributors may be used to endorse or promote products derived from
+ *          this software without specific prior written permission.
+ *
+ *     NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
+ *     BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
+ *     BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ *     FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *     HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ *     TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ *     PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *     LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *     NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ *     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+use std::fmt;
+
+/// A single option.
+///
+/// For `Opt(x, y)`:
+///   - `x` is the character representing the option.
+///   - `y` is `Some` string, or `None` if no argument was expected.
+///
+/// # Example
+///
+/// ```
+/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
+/// use getopt::Opt;
+///
+/// // args = ["program", "-abc", "foo"];
+/// # let args: Vec<String> = vec!["program", "-abc", "foo"]
+/// #     .into_iter()
+/// #     .map(String::from)
+/// #     .collect();
+/// let optstring = "ab:c";
+/// let mut opts = getopt::Parser::new(&args, optstring);
+///
+/// assert_eq!(Opt('a', None), opts.next().transpose()?.unwrap());
+/// assert_eq!(Opt('b', Some("c".to_string())), opts.next().transpose()?.unwrap());
+/// assert_eq!(None, opts.next().transpose()?);
+/// # Ok(())
+/// # }
+/// ```
+#[derive(Debug, Eq, Ord, PartialEq, PartialOrd)]
+pub struct Opt(pub char, pub Option<String>);
+
+impl fmt::Display for Opt {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Opt({:?}, {:?})", self.0, self.1)
+    }
+}

src/getopt-rs/parser.rs

@@ -0,0 +1,382 @@
+/*
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ *
+ * This file incorporates work covered by the following copyright and permission
+ * notice:
+ *     The Clear BSD License
+ *
+ *     Copyright © 2017-2023 David Wildasin
+ *     All rights reserved.
+ *
+ *     Redistribution and use in source and binary forms, with or without
+ *     modification, are permitted (subject to the limitations in the disclaimer
+ *     below) provided that the following conditions are met:
+ *
+ *          * Redistributions of source code must retain the above copyright
+ *          notice, this list of conditions, and the following disclaimer.
+ *
+ *          * Redistributions in binary form must reproduce the above copyright
+ *          notice, this list of conditions, and the following disclaimer in the
+ *          documentation and/or other materials provided with the distribution.
+ *
+ *          * Neither the name of the copyright holder nor the names of its
+ *          contributors may be used to endorse or promote products derived from
+ *          this software without specific prior written permission.
+ *
+ *     NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
+ *     BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
+ *     BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ *     FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *     HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ *     TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ *     PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *     LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *     NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ *     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+use std::collections::HashMap;
+
+use crate::{ error::Error, errorkind::ErrorKind, opt::Opt, result::Result };
+
+/// The core of the `getopt` crate.
+///
+/// `Parser` is implemented as an iterator over the options present in the given
+/// argument vector.
+///
+/// The method [`next`](#method.next) does the heavy lifting.
+///
+/// # Examples
+///
+/// ## Simplified usage:
+/// ```
+/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
+/// use getopt::Opt;
+///
+/// // args = ["program", "-abc", "foo"];
+/// # let args: Vec<String> = vec!["program", "-abc", "foo"]
+/// #     .into_iter()
+/// #     .map(String::from)
+/// #     .collect();
+/// let mut opts = getopt::Parser::new(&args, "ab:c");
+///
+/// assert_eq!(Some(Opt('a', None)), opts.next().transpose()?);
+/// assert_eq!(1, opts.index());
+/// assert_eq!(Some(Opt('b', Some("c".to_string()))), opts.next().transpose()?);
+/// assert_eq!(2, opts.index());
+/// assert_eq!(None, opts.next());
+/// assert_eq!(2, opts.index());
+/// assert_eq!("foo", args[opts.index()]);
+/// # Ok(())
+/// # }
+/// ```
+///
+/// ## A more idiomatic example:
+/// ```
+/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
+/// use getopt::Opt;
+///
+/// // args = ["program", "-abc", "-d", "foo", "-e", "bar"];
+/// # let mut args: Vec<String> = vec!["program", "-abc", "-d", "foo", "-e", "bar"]
+/// #     .into_iter()
+/// #     .map(String::from)
+/// #     .collect();
+/// let mut opts = getopt::Parser::new(&args, "ab:cd:e");
+///
+/// let mut a_flag = false;
+/// let mut b_flag = String::new();
+/// let mut c_flag = false;
+/// let mut d_flag = String::new();
+/// let mut e_flag = false;
+///
+/// loop {
+///     match opts.next().transpose()? {
+///         None => break,
+///         Some(opt) => match opt {
+///             Opt('a', None) => a_flag = true,
+///             Opt('b', Some(arg)) => b_flag = arg.clone(),
+///             Opt('c', None) => c_flag = true,
+///             Opt('d', Some(arg)) => d_flag = arg.clone(),
+///             Opt('e', None) => e_flag = true,
+///             _ => unreachable!(),
+///         },
+///     }
+/// }
+///
+/// let new_args = args.split_off(opts.index());
+///
+/// assert_eq!(true, a_flag);
+/// assert_eq!("c", b_flag);
+/// assert_eq!(false, c_flag);
+/// assert_eq!("foo", d_flag);
+/// assert_eq!(true, e_flag);
+///
+/// assert_eq!(1, new_args.len());
+/// assert_eq!("bar", new_args.first().unwrap());
+/// # Ok(())
+/// # }
+/// ```
+#[derive(Debug, Eq, PartialEq)]
+pub struct Parser {
+    opts: HashMap<char, bool>,
+    args: Vec<Vec<char>>,
+    index: usize,
+    point: usize,
+}
+
+impl Parser {
+    /// Create a new `Parser`, which will process the arguments in `args`
+	/// according to the options specified in `optstring`.
+    ///
+    /// For compatibility with
+	/// [`std::env::args`](https://doc.rust-lang.org/std/env/fn.args.html),
+    /// valid options are expected to begin at the second element of `args`, and
+	/// `index` is
+    /// initialised to `1`.
+    /// If `args` is structured differently, be sure to call
+	/// [`set_index`](#method.set_index) before the first invocation of
+	/// [`next`](#method.next).
+    ///
+    /// `optstring` is a string of recognised option characters; if a character
+	/// is followed by a colon (`:`), that option takes an argument.
+    ///
+    /// # Note:
+    /// Transforming the OS-specific argument strings into a vector of `String`s
+	/// is the sole responsibility of the calling program, as it involves some
+	/// level of potential information loss (which this crate does not presume
+	/// to handle unilaterally) and error handling (which would complicate the
+	/// interface).
+    pub fn new(args: &[String], optstring: &str) -> Self {
+        let optstring: Vec<char> = optstring.chars().collect();
+        let mut opts = HashMap::new();
+        let mut i = 0;
+        let len = optstring.len();
+
+        while i < len {
+            let j = i + 1;
+
+            if j < len && optstring[j] == ':' {
+                opts.insert(optstring[i], true);
+                i += 1;
+            } else {
+                opts.insert(optstring[i], false);
+            }
+            i += 1;
+        }
+
+        Self {
+            opts,
+            // "explode" the args into a vector of character vectors, to allow
+			// indexing
+            args: args.iter().map(|e| e.chars().collect()).collect(),
+            index: 1,
+            point: 0,
+        }
+    }
+
+    /// Return the current `index` of the parser.
+    ///
+    /// `args[index]` will always point to the the next element of `args`; when
+	/// the parser is
+    /// finished with an element, it will increment `index`.
+    ///
+    /// After the last option has been parsed (and [`next`](#method.next) is
+	/// returning `None`),
+    /// `index` will point to the first non-option argument.
+    pub fn index(&self) -> usize {
+        self.index
+    }
+
+    // `point` must be reset to 0 whenever `index` is changed
+
+    /// Modify the current `index` of the parser.
+    pub fn set_index(&mut self, value: usize) {
+        self.index = value;
+        self.point = 0;
+    }
+
+    /// Increment the current `index` of the parser.
+    ///
+    /// This use case is common enough to warrant its own optimised method.
+    pub fn incr_index(&mut self) {
+        self.index += 1;
+        self.point = 0;
+    }
+}
+
+impl Iterator for Parser {
+    type Item = Result<Opt>;
+
+    /// Returns the next option, if any.
+    ///
+    /// Returns an [`Error`](struct.Error.html) if an unexpected option is
+	/// encountered or if an
+    /// expected argument is not found.
+    ///
+    /// Parsing stops at the first non-hyphenated argument; or at the first
+	/// argument matching "-";
+    /// or after the first argument matching "--".
+    ///
+    /// When no more options are available, `next` returns `None`.
+    ///
+    /// # Examples
+    ///
+    /// ## "-"
+    /// ```
+    /// use getopt::Parser;
+    ///
+    /// // args = ["program", "-", "-a"];
+    /// # let args: Vec<String> = vec!["program", "-", "-a"]
+    /// #     .into_iter()
+    /// #     .map(String::from)
+    /// #     .collect();
+    /// let mut opts = Parser::new(&args, "a");
+    ///
+    /// assert_eq!(None, opts.next());
+    /// assert_eq!("-", args[opts.index()]);
+    /// ```
+    ///
+    /// ## "--"
+    /// ```
+    /// use getopt::Parser;
+    ///
+    /// // args = ["program", "--", "-a"];
+    /// # let args: Vec<String> = vec!["program", "--", "-a"]
+    /// #     .into_iter()
+    /// #     .map(String::from)
+    /// #     .collect();
+    /// let mut opts = Parser::new(&args, "a");
+    ///
+    /// assert_eq!(None, opts.next());
+    /// assert_eq!("-a", args[opts.index()]);
+    /// ```
+    ///
+    /// ## Unexpected option:
+    /// ```
+    /// use getopt::Parser;
+    ///
+    /// // args = ["program", "-b"];
+    /// # let args: Vec<String> = vec!["program", "-b"]
+    /// #     .into_iter()
+    /// #     .map(String::from)
+    /// #     .collect();
+    /// let mut opts = Parser::new(&args, "a");
+    ///
+    /// assert_eq!(
+    ///     "unknown option -- 'b'".to_string(),
+    ///     opts.next().unwrap().unwrap_err().to_string()
+    /// );
+    /// ```
+    ///
+    /// ## Missing argument:
+    /// ```
+    /// use getopt::Parser;
+    ///
+    /// // args = ["program", "-a"];
+    /// # let args: Vec<String> = vec!["program", "-a"]
+    /// #     .into_iter()
+    /// #     .map(String::from)
+    /// #     .collect();
+    /// let mut opts = Parser::new(&args, "a:");
+    ///
+    /// assert_eq!(
+    ///     "option requires an argument -- 'a'".to_string(),
+    ///     opts.next().unwrap().unwrap_err().to_string()
+    /// );
+    /// ```
+    fn next(&mut self) -> Option<Result<Opt>> {
+        if self.point == 0 {
+            /*
+             * Rationale excerpts below taken verbatim from "The Open Group Base
+			 * Specifications Issue 7, 2018 edition", IEEE Std 1003.1-2017
+			 * (Revision of IEEE Std 1003.1-2008).
+             * Copyright © 2001-2018 IEEE and The Open Group.
+             */
+
+            /*
+             * If, when getopt() is called:
+             *      argv[optind]    is a null pointer
+             *      *argv[optind]   is not the character '-'
+             *      argv[optind]    points to the string "-"
+             * getopt() shall return -1 without changing optind.
+             */
+            if self.index >= self.args.len()
+                || self.args[self.index].is_empty()
+                || self.args[self.index][0] != '-'
+                || self.args[self.index].len() == 1
+            {
+                return None;
+            }
+
+            /*
+             * If:
+             *      argv[optind]    points to the string "--"
+             * getopt() shall return -1 after incrementing index.
+             */
+            if self.args[self.index][1] == '-' && self.args[self.index].len() == 2 {
+                self.incr_index();
+                return None;
+            }
+
+            // move past the starting '-'
+            self.point += 1;
+        }
+
+        let opt = self.args[self.index][self.point];
+        self.point += 1;
+
+        match self.opts.get(&opt) {
+            None => {
+                if self.point >= self.args[self.index].len() {
+                    self.incr_index();
+                }
+                Some(Err(Error::new(ErrorKind::UnknownOption, opt)))
+            }
+            Some(false) => {
+                if self.point >= self.args[self.index].len() {
+                    self.incr_index();
+                }
+
+                Some(Ok(Opt(opt, None)))
+            }
+            Some(true) => {
+                let arg: String = if self.point >= self.args[self.index].len() {
+                    self.incr_index();
+                    if self.index >= self.args.len() {
+                        return Some(Err(Error::new(
+									ErrorKind::MissingArgument,
+									opt,
+								)));
+                    }
+                    self.args[self.index].iter().collect()
+                } else {
+                    self.args[self.index]
+                        .clone()
+                        .split_off(self.point)
+                        .iter()
+                        .collect()
+                };
+
+                self.incr_index();
+
+                Some(Ok(Opt(opt, Some(arg))))
+            }
+        }
+    }
+}

src/getopt-rs/result.rs

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ *
+ * This file incorporates work covered by the following copyright and permission
+ * notice:
+ *     The Clear BSD License
+ *
+ *     Copyright © 2017-2023 David Wildasin
+ *     All rights reserved.
+ *
+ *     Redistribution and use in source and binary forms, with or without
+ *     modification, are permitted (subject to the limitations in the disclaimer
+ *     below) provided that the following conditions are met:
+ *
+ *          * Redistributions of source code must retain the above copyright
+ *          notice, this list of conditions, and the following disclaimer.
+ *
+ *          * Redistributions in binary form must reproduce the above copyright
+ *          notice, this list of conditions, and the following disclaimer in the
+ *          documentation and/or other materials provided with the distribution.
+ *
+ *          * Neither the name of the copyright holder nor the names of its
+ *          contributors may be used to endorse or promote products derived from
+ *          this software without specific prior written permission.
+ *
+ *     NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
+ *     BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
+ *     BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ *     FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *     HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ *     TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ *     PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *     LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *     NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ *     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+use std::result;
+
+use crate::error::Error;
+
+/// A specialized `Result` type for use with [`Parser`](struct.Parser.html)
+pub type Result<T> = result::Result<T, Error>;

src/getopt-rs/tests.rs

@@ -0,0 +1,228 @@
+/*
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ *
+ * This file incorporates work covered by the following copyright and permission
+ * notice:
+ *     The Clear BSD License
+ *
+ *     Copyright © 2017-2023 David Wildasin
+ *     All rights reserved.
+ *
+ *     Redistribution and use in source and binary forms, with or without
+ *     modification, are permitted (subject to the limitations in the disclaimer
+ *     below) provided that the following conditions are met:
+ *
+ *          * Redistributions of source code must retain the above copyright
+ *          notice, this list of conditions, and the following disclaimer.
+ *
+ *          * Redistributions in binary form must reproduce the above copyright
+ *          notice, this list of conditions, and the following disclaimer in the
+ *          documentation and/or other materials provided with the distribution.
+ *
+ *          * Neither the name of the copyright holder nor the names of its
+ *          contributors may be used to endorse or promote products derived from
+ *          this software without specific prior written permission.
+ *
+ *     NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
+ *     BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
+ *     BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ *     FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *     HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ *     TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ *     PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *     LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *     NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ *     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+use crate::{Opt, Parser};
+
+macro_rules! basic_test {
+    ($name:ident, $expect:expr, $next:expr, [$($arg:expr),+], $optstr:expr) => (
+        #[test]
+        fn $name() -> Result<(), String> {
+            let expect: Option<Opt> = $expect;
+            let args: Vec<String> = vec![$($arg),+]
+				.into_iter()
+				.map(String::from)
+				.collect();
+            let next: Option<String> = $next;
+            let mut opts = Parser::new(&args, $optstr);
+
+            match opts.next().transpose() {
+                Err(error) => {
+                    return Err(format!("next() returned {:?}", error))
+                },
+                Ok(actual) => if actual != expect {
+                    return Err(
+						format!("expected {:?}; got {:?}", expect, actual)
+					)
+                },
+            };
+
+            match next {
+                None => if opts.index() < args.len() {
+                    return Err(format!(
+							"expected end of args; got {:?}", args[opts.index()]
+					))
+                },
+                Some(n) => if args[opts.index()] != n {
+                    return Err(format!(
+							"next arg: expected {:?}; got {:?}",
+							n,
+							args[opts.index()]
+					))
+                },
+            };
+
+            Ok(())
+        }
+    )
+}
+
+#[rustfmt::skip] basic_test!(
+	blank_arg, None, Some(String::new()), ["x", ""], "a"
+);
+#[rustfmt::skip] basic_test!(
+	double_dash, None, Some("-a".to_string()), ["x", "--", "-a", "foo"], "a"
+);
+#[rustfmt::skip] basic_test!(no_opts_1, None, None, ["x"], "a");
+#[rustfmt::skip] basic_test!(
+	no_opts_2, None, Some("foo".to_string()), ["x", "foo"], "a"
+);
+#[rustfmt::skip] basic_test!(
+	no_opts_3, None, Some("foo".to_string()), ["x", "foo", "-a"], "a"
+);
+#[rustfmt::skip] basic_test!(
+	single_dash, None, Some("-".to_string()), ["x", "-", "-a", "foo"], "a"
+);
+#[rustfmt::skip] basic_test!(
+	single_opt,
+	Some(Opt('a', None)),
+	Some("foo".to_string()),
+	["x", "-a", "foo"],
+	"a"
+);
+#[rustfmt::skip] basic_test!(
+	single_optarg,
+	Some(Opt('a', Some("foo".to_string()))),
+	None,
+	["x", "-a", "foo"],
+	"a:"
+);
+
+macro_rules! error_test {
+    ($name:ident, $expect:expr, [$($arg:expr),+], $optstr:expr) => (
+        #[test]
+        fn $name() -> Result<(), String> {
+            let expect: String = $expect.to_string();
+            let args: Vec<String> = vec![$($arg),+]
+				.into_iter()
+				.map(String::from)
+				.collect();
+            let mut opts = Parser::new(&args, $optstr);
+
+            match opts.next() {
+                None => {
+                    return Err(format!(
+							"unexpected successful response: end of options"
+					))
+                },
+                Some(Err(actual)) => {
+                    let actual = actual.to_string();
+
+                    if actual != expect {
+                        return Err(
+							format!("expected {:?}; got {:?}", expect, actual)
+						);
+                    }
+                },
+                Some(Ok(opt)) => {
+                    return Err(
+						format!("unexpected successful response: {:?}", opt)
+					)
+                },
+            };
+
+            Ok(())
+        }
+    )
+}
+
+#[rustfmt::skip] error_test!(
+	bad_opt,
+	"unknown option -- 'b'",
+	["x", "-b"],
+	"a"
+);
+
+#[rustfmt::skip] error_test!(
+	missing_optarg,
+	"option requires an argument -- 'a'",
+	["x", "-a"],
+	"a:"
+);
+
+#[test]
+fn multiple() -> Result<(), String> {
+    let args: Vec<String> = vec!["x", "-abc", "-d", "foo", "-e", "bar"]
+        .into_iter()
+        .map(String::from)
+        .collect();
+    let optstring = "ab:d:e".to_string();
+    let mut opts = Parser::new(&args, &optstring);
+
+    macro_rules! check_result {
+        ($expect:expr) => {
+            let expect: Option<Opt> = $expect;
+            match opts.next().transpose() {
+                Err(error) => {
+					return Err(format!("next() returned {:?}", error));
+				},
+                Ok(actual) => {
+                    if actual != expect {
+                        return Err(
+							format!("expected {:?}; got {:?}", expect, actual)
+						);
+                    }
+                }
+            };
+        };
+    }
+
+    check_result!(Some(Opt('a', None)));
+    check_result!(Some(Opt('b', Some("c".to_string()))));
+    check_result!(Some(Opt('d', Some("foo".to_string()))));
+    check_result!(Some(Opt('e', None)));
+    check_result!(None);
+
+    Ok(())
+}
+
+#[test]
+fn continue_after_error() {
+    let args: Vec<String> = vec!["x", "-z", "-abc"]
+        .into_iter()
+        .map(String::from)
+        .collect();
+    let optstring = "ab:d:e".to_string();
+    for _opt in Parser::new(&args, &optstring) {
+        // do nothing, should not panic
+    }
+}

src/getopt.rs

@@ -1,118 +0,0 @@
-/*
- * Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
- * SPDX-License-Identifier: LGPL-3.0-or-later
- *
- * This program is free software: you can redistribute it and/or modify it under
- * the terms of the GNU Lesser General Public License as published by the Free
- * Software Foundation, either version 3 of the License, or (at your option) any
- * later version.
- * 
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
- * details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program. If not, see https://www.gnu.org/licenses/.
- */
-
-use std::ffi::{ c_int, c_char, CString, CStr };
-
-pub struct Opt {
-	pub arg: Option<String>,
-	pub ind: i32,
-	pub opt: String,
-}
-
-pub enum OptError {
-	MissingArg(String),
-	UnknownOpt(String),
-}
-
-/* function signature */
-pub trait GetOpt {
-	fn getopt(&self, optstring: &str) -> Option<Result<Opt, OptError>>;
-}
-
-impl GetOpt for Vec<String> {
-    fn getopt(&self, optstring: &str) -> Option<Result<Opt, OptError>> {
-        let c_strings: Vec<_> = self
-			.iter()
-			.cloned()
-			.map(CString::new)
-			.map(Result::unwrap)
-			.collect();
-
-		/* these operations must be separated out into separate operations so
-		 * the CStrings can live long enough */
-        let argv: Vec<_> = c_strings.iter().map(|x| x.as_ptr()).collect();
-        let argv_ptr = argv.as_ptr() as *const *mut c_char;
-        let opts = CString::new(optstring).unwrap().into_raw();
-        let len = self.len() as c_int;
-
-        unsafe { // TODO: enable optind modification
-            match getopt(len, argv_ptr, opts) { 
-				/* From getopt(3p):
-				 *
-				 * The getopt() function shall return the next option character
-				 * specified on the command line.
-				 *
-				 * A <colon> (':') shall be returned if getopt() detects a
-				 * missing argument and the first character of optstring was a
-				 * <colon> (':').
-				 *
-				 * A <question-mark> ('?') shall be returned if getopt()
-				 * encounters an option character not in optstring or detects a
-				 * missing argument and the first character of optstring was not
-				 * a <colon> (':').
-				 *
-				 * Otherwise, getopt() shall return -1 when all command line
-				 * options are parsed. */
-                58 => { /* numerical ASCII value for ':' */
-					Some(Err(OptError::MissingArg(optopt.to_string())))
-				},
-                63 => { /* numerical ASCII value for '?' */
-					Some(Err(OptError::UnknownOpt(optopt.to_string())))
-				},
-				/* From getopt(3p):
-				 *
-				 * If, when getopt() is called:
-				 *
-				 * argv[optind]  is a null pointer
-				 * *argv[optind]  is not the character -
-				 * argv[optind]  points to the string "-"
-				 *
-				 * getopt() shall return -1 without changing optind.  If:
-				 *
-				 * argv[optind]   points to the string "--"
-				 *
-				 * getopt() shall return -1 after incrementing optind. */
-                -1 => return None,
-                opt => {
-					let arg = CStr::from_ptr(optarg)
-						.to_string_lossy()
-						.into_owned();
-
-					Some(Ok(Opt {
-						arg: Some(arg), /* opt argument */
-						ind: optind, /* opt index */
-						opt: opt.to_string(), /* option itself */
-					}))
-				},
-            }
-        }
-    }
-}
-/* binding to getopt(3p) */
-extern "C" {
-	static mut optarg: *mut c_char;
-	static mut _opterr: c_int;
-	static mut optind: c_int;
-	static mut optopt: c_int;
-
-	fn getopt(
-		___argc: c_int,
-		___argv: *const *mut c_char,
-		__shortopts: *const c_char,
-	) -> c_int;
-}

src/hru.rs

@@ -23,10 +23,8 @@ use std::{
 	process::{ ExitCode, exit },
 };
 
-extern crate strerror;
 extern crate sysexits;
 
-use strerror::StrError;
 use sysexits::{ EX_DATAERR, EX_IOERR, EX_SOFTWARE };
 
 const LIST: [(u32, &str); 10] = [
@@ -51,7 +49,7 @@ fn convert(input: u128) -> Result<(f64, (u32, &'static str)), String> {
 		let c = match 10_u128.checked_pow(n) {
 			Some(c) => c,
 			None => {
-				return Err(format!("10^{}: Integer overflow", n.to_string()));
+				return Err(format!("10^{}: Integer overflow.", n.to_string()));
 			},
 		};
 
@@ -81,7 +79,7 @@ fn main() -> ExitCode {
 				f
 			},
 			Err(err) => {
-				eprintln!("{}: {}", argv[0], err);
+				eprintln!("{}: {}.", argv[0], err);
 				return ExitCode::from(EX_DATAERR as u8);
 			},
 		};
@@ -89,7 +87,7 @@ fn main() -> ExitCode {
 		let (number, prefix) = match convert(n) {
 			Ok(x) => x,
 			Err(err) => {
-				eprintln!("{}: {}", argv[0], err);
+				eprintln!("{}: {}.", argv[0], err);
 				return ExitCode::from(EX_SOFTWARE as u8);
 			},
 		};
@@ -100,7 +98,7 @@ fn main() -> ExitCode {
 
 		stdout().write_all(format!("{} {}\n", out, si_prefix).as_bytes())
 			.unwrap_or_else(|e| {
-				eprintln!("{}: {}", argv[0], e.strerror());
+				eprintln!("{}: {}.", argv[0], e);
 				exit(EX_IOERR);
 			});
 	}

src/rpn.rs

@@ -172,7 +172,7 @@ fn eval(
 					};
 				} else {
 					return Err(EvaluationError {
-						message: format!("{}: Unexpected operation", op),
+						message: format!("{}: Unexpected operation.", op),
 						code: EX_DATAERR,
 					})
 				}

src/strerror.rs

@@ -1,31 +0,0 @@
-/*
- * Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
- * SPDX-License-Identifier: FSFAP
- *
- * Copying and distribution of this file, with or without modification, are
- * permitted in any medium without royalty provided the copyright notice and
- * this notice are preserved.  This file is offered as-is, without any warranty.
- */
-
-use std::ffi::{ c_int, c_char, CStr };
-
-pub trait StrError { fn strerror(&self) -> String; }
-
-impl StrError for std::io::Error {
-	/* wrapper function for use in Rust */
-	fn strerror(&self) -> String {
-		/* Get the raw OS error. If it’s None, what the hell is going on‽ */
-		let errno = self.raw_os_error().unwrap_or(0) as c_int;
-
-		/* Get a CStr from the error message so that it’s referenced and then
-		 * convert it to an owned value. If the string is not valid UTF-8,
-		 * return that error instead. */
-		match unsafe { CStr::from_ptr(strerror(errno)) }.to_str() {
-			Ok(s) => s.to_owned(), // yay!! :D
-			Err(e) => e.to_string(), // awww :(
-		}
-	}
-}
-
-/* binding to strerror(3p) */
-extern "C" { fn strerror(errnum: c_int) -> *mut c_char; }

src/test.rs

@@ -1,10 +0,0 @@
-extern crate strerror;
-
-use strerror::raw_message;
-
-fn main() {
-	stdout.write_all(b"meow\n").unwrap_or_else(|e| {
-		eprintln!("{}", raw_message(e));
-		std::process::exit(1);
-	});
-}