2026-01-13  Norwid Behrnd <nbehrnd@yahoo.com>

	* examples/lsd.chem: Improve visual representation.  Reorganize
	representation of the structure.
	- For aesthetic appeal, the structure was a rotated little bit.
	  Its orientation is the one of ergoline, the parent hydride
	  {in chemists' terms, the senior or reference structure motive}
	  lsd and other ergot alkaloids derive from as displayed in
	  appendix 3 of [1a], and publications (e.g., [2-4]).  The
	  edit retains the pragmatic definition of the pyrrole moiety
	  based on keyword flatring.
	- The backbone labels the rings A, B, C, and D.  This is both
	  for backward compatibility in nomenclature (rule P-101.2.4
	  in [1b]) still used in peer reviewed publications today {e.g.,
	  [2-4]} as well as showcase of chem's flexibilty of definitions
	  coined by the user.
	- Some cleaning according e.g., to rules GR-4.1.1, 4.1.2,
	  6.5.[5]

	[1a] Nomenclature of Organic Chemistry: IUPAC Recommendations
	     and Preferred Names 2013; Favre, H. A., Powell, W. H.,
	     International Union of Pure and Applied Chemistry, Eds.;
	     Royal Society of Chemistry: Cambridge, 2014. Authorized
	     online excerpt:
	     https://iupac.qmul.ac.uk/BlueBook/Papp3.html
	[1b] Same as [1a], authorized online excerpt:
	     https://iupac.qmul.ac.uk/BlueBook/P10.html#1010204
	[2]  Barker, S. A. Simple Analogs of the LSD D-Ring: A
	     Consideration of Structure–Activity Relationships and Their
	     Potential as Therapeutics. ACS Chem. Neurosci. 2025, 16
	     (22), 4309–4314.
	     https://doi.org/10.1021/acschemneuro.5c00695.
	[3]  Pazur, E. J.; Kalatanova, A.; Tasker, N. R.; Vainionpää,
	     K.; Leinonen, H.; Wipf, P. Synthesis and Biological
	     Analysis of Iso-Dimethyltryptamines in a Model of
	     Light-Induced Retinal Degeneration. ACS Med. Chem. Lett.
	     2024, 15 (7), 1049–1056.
	     https://doi.org/10.1021/acsmedchemlett.4c00130.
	[4]  Rathnayake, U.; Garner, P. Asymmetric Synthesis of Lysergic
	     Acid via an Intramolecular (3+2) Dipolar Cycloaddition/
	     Ring-Expansion Sequence. Org. Lett. 2021, 23 (17),
	     6756–6759.
	     https://doi.org/10.1021/acs.orglett.1c02337.
	[5]  Brecher, J. Graphical Representation Standards for Chemical
	     Structure Diagrams (IUPAC Recommendations 2008). Pure Appl.
	     Chem. 2008, 80 (2), 277–410.
	     https://doi.org/10.1351/pac200880020277.

2026-01-01  Norwid Behrnd <nbehrnd@yahoo.com>

	* examples/penicillin.chem: Reorganize file.
	- Improve use of the ring templates.
	- Prevent partial overwrite of N in lactam moiety and alkyl
	  amide.
	- Explicitly designate stereochemistry.  If available, future
	  versions of chem should replace `backbond` by a wegde shaped
	  variant of this bond.

	...for better visual representation similar to the one currently
	used on Wikipedia.[1]

	Fixes <https://savannah.gnu.org/bugs/?67877>.

	[1] https://en.wikipedia.org/wiki/Benzylpenicillin

2026-01-01  Norwid Behrnd <nbehrnd@yahoo.com>

	* examples/ethamivan.chem: Improve visual representation.
	Reorganize representation of the structure.
	- Contract the hydroxyl group, both simplifying the definition
	  of the substituent and correcting the unusual dihedral angle
	  of 180 degrees about C-O-H previously used.
	- Adjust orientations of the drawing overall and substituents
	  (e.g., rules GR-3.1.2, GR-3.1.3; 3.2.1 in [1]), especially
	  alkyl chains around N (GR-4.1.1, ibid.).

	...as one would "clean" the structure drawing in a GUI-based
	editor, and indeed with a result very similar to the current
	depiction on Wikipedia.[2]

	Fixes <https://savannah.gnu.org/bugs/?67876>.

	[1] Brecher, J. Graphical Representation Standards for Chemical
	Structure Diagrams (IUPAC Recommendations 2008). Pure Appl.
	Chem.  2008, 80 (2), 277-410.
	https://doi.org/10.1351/pac200880020277.
	[2] https://en.wikipedia.org/wiki/Etamivan

2025-12-31  Norwid Behrnd <nbehrnd@yahoo.com>

	* examples/cholesterol.chem: Add stereochemistry.
	- The previous depiction was incomplete and did not explicitly
	  described the stereogenic centres as such.  This information
	  was added with `front bond` and `back bond` as available with
	  groff 1.23.0.  If possible, future versions should use a wedge
	  shaped version of `back bond`.
	- Particular about steroids: among chemists, it is more common
	  to name the four rings by A, B, C, and D.  To use these labels
	  instead of R1, R2, etc. equally displays chem's flexibility
	  here.
	- The orientation of cycles allowed simplifying the definition
	  of their mutual attachment.

	Fixes <https://savannah.gnu.org/bugs/?67873>.

2025-12-31  Norwid Behrnd <nbehrnd@yahoo.com>

	* examples/cholesterin.chem: Rename this...
	* examples/cholesterol.chem: ...to this.
	* chem.am (EXTRA_DIST): Reflect rename.

2026-01-05  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.pl (version): Restore here-document marker that I
	thoughtlessly discarded in commit 5d777599d5, 29 December.

2026-01-05  G. Branden Robinson <g.branden.robinson@gmail.com>

	* tests/smoke-test.sh: Add (directory and) test script.
	* chem.am: Add script to new `chem_TESTS` macro and append that
	macro to `TESTS` macro, so that "make check" runs the test.
	Append `chem_TESTS` to `EXTRA_DIST`, so that the test script
	ships in distribution archives.

2025-12-31  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.am (EXTRA_DIST): Ship "COPYRIGHT" file in distribution
	archive.

2025-12-29  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.pl: Drop `copyright` scalar; see below.  Bump revision or
	"micro" portion of version number.
	(version): Stop reporting copyright and license notice
	after version disclosure.  No other program groff installs, not
	even others authored by Bernd Warken, handles `--version` in
	this way, except for the namesake program groff(1) itself.

2025-12-29  G. Branden Robinson <g.branden.robinson@gmail.com>

	* examples/122: Rename this directory...
	* examples/cstr-122: ...to this.
	* chem.am (chemexample122dir, EXTRA_DIST, install_chem_extra)
	(uninstall_chem_hook, dist_chem): Update macro and rule
	definitions accordingly.

2025-12-20  G. Branden Robinson <g.branden.robinson@gmail.com>

	Our README files no longer contain '@g@' sequences, so they no
	longer require build-time processing.

	* README.txt:
	* examples/README.txt:
	* examples/122/README.txt: Rename these...
	* README:
	* examples/README:
	* examples/122/README: ...to these.
	* chem.am (EXTRA_DIST): Ship the suffixless files instead of
	their now-nonexistent suffixed counterparts.
	(contrib/chem/README)
	(contrib/chem/examples/README)
	(contrib/chem/examples/122/README): Drop target rules for
	creating these files now that they already exist in the source
	tree.
	(CHEM_GENEXAMPLES, nodist_chemexample_DATA)
	nodist_chemexample122_DATA): Drop now-unneeded macro
	definitions.
	(CHEM_EXAMPLES): Add "README" file.
	(install_chem_extra): Update "lazy" `for` loop to install
	"122/README" file as well, not just the files ending in `.chem`.
	(MOSTLYCLEANFILES): Drop now-unneeded macro appendment.

2025-12-18  G. Branden Robinson <g.branden.robinson@gmail.com>

	* GPLv2: New file.
	* chem.am (EXTRA_DIST): Ship it.

	The GNU GPLv2 covers Bernd Warken's work on chem through 27
	August 2015.  Copyrightable changes to chem since September 2017
	are licensed under the GNU GPLv3, not GPLv2.

2025-12-09  Norwid Behrnd <nbehrnd@yahoo.com>

	* examples/atp.chem: The previous depiction of the ATP molecule
	omitted a nitrogen atom in the pyrimidine moiety.

	Fixes <https://savannah.gnu.org/bugs/?67792>.

2024-12-21  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.am (all): Drop seemingly spurious use of target.

2024-12-12  G. Branden Robinson <g.branden.robinson@gmail.com>

	Move "chem.pic" from its own subdirectory (which has no other
	contents provided by groff) to the "tmac" directory.  The
	"eqnrc" file and groff's hyphenation pattern and exception files
	establish a precedent for using "tmac" for things that aren't
	"troff macro" files.  This makes it easier to run automated
	tests on GNU chem from the build tree.

	* chem.am (chempicdir, dist_chempic_DATA): Drop macros.
	(CHEMTMACFILES, chemtmacdir, dist_chemtmac_DATA): Add macros.
	(uninstall_chem_extra): Rename this...
	(uninstall_chem_hook): ...to this, for consistency with other
	groff Automake files.
	* chem.pl: If running as "built" version of script, locate
	"chem.pic" file relative to the build's "tmac" directory.

2024-12-11  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.pl: Revise approach to determining program name.  This
	reverts the change on 9 December; the Perl interpreter does not
	populate `argv[0]` the same way that the shell typically does
	with execve(2).  Drop global scalar `chem` in favor of a new
	global scalar `prog`, populated by `File::Spec->splitpath()`.
	(usage, version): Migrate from `chem` to `prog`.
	(usage): Report only the "basename" of the script.  Revise and
	shorten command description.

2024-12-09  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.pl (usage): Revise usage message.  Organize like other
	groff commands' usage messages.  Use $0 in the synopses for
	consistency with groff's C++ programs.  This also informs the
	user with multiple versions available which they are running.

2024-12-09  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.am (chem): Use sed to replace magic token `@PERL@` with
	contents of `PERL` macro, determined by groff configure script.
	* chem.pl: Rewrite shebang line to use the magic token.

2023-07-17  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.pl: Stop endorsing shebang line space myth.  See
	<https://savannah.gnu.org/bugs/?64058>.

2022-08-18  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.pl: Refactor.
	  - Rename scalars.
	    Copyright -> copyright
	    Program_Version -> chem_version
	    Groff_Version -> groff_version
	    Chem_Name -> chem
	    before_make -> is_in_source_tree
	  - Rename hash.
	    at_at -> makevar
	  - Drop unused hash member `$makevar{'BINDIR'}`.
	  - Drop scalar `Groff_Version_Preset`, which apparently hadn't
	    been updated since groff 1.20.  Instead, follow grog(1) and
	    set the `groff_version` scalar to "DEVELOPMENT" if this is
	    the version from the groff source tree.  Overwrite its value
	    with that determined by make(1) if available.
	  - Tighten usage and version messages; make the latter more
	    conformant with the format recommended in the GNU Coding
	    Standards.  Explicitly identify license as GNU GPLv2.
	  (usage): Refer to "pic" with its command prefix if it is known
	  to have one.  (If running "unbuilt", we have no way to know.)

2022-08-18  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.pl: Stop copying "pic.tmac" (fallback troff macro
	definitions) into the output.  It might not be necessary and it
	is inappropriate to do so if a macro package offers its own
	definitions or the user has made other arrangements on the
	command line.  (The same thing can be achieved with the "-mpic"
	argument to the formatter or a front end.)  Bump version number.

2022-06-15  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.1.man: Fix markup nits.  Use idiomatic input style,
	placing newlines after sentences and commas.  Also put an empty
	request between sentences.

	Fixes <https://savannah.gnu.org/bugs/?51328>.

2022-04-12  Ingo Schwarze <schwarze@openbsd.org>

	Delete the harmful, ill-designed, buggy, and essentially
	unmaintained and untested --with-doc option of the configure
	script.  See the NEWS file for more details on the rationale.

	* chem.am: Delete three BUILD_EXAMPLES conditionals.

2020-04-22  G. Branden Robinson <g.branden.robinson@gmail.com>

	* chem.1.man:
	* examples/122/README.txt:
	* examples/README.txt: Delete references to groffer.

2018-02-28  Werner LEMBERG  <wl@gnu.org>

	* chem.am (chem, README): Use $(AM_V_GEN) to silence file generation.

2015-08-22  Bernd Warken  <bernd.warken@web.de>

	* chem.1.man: Rename `chem.man'.

	* chem.am: Include renaming.

2015-08-05  Bernd Warken  <bernd.warken@web.de>

	* chem.am: Add `Last update'.  Setup Emacs makefile-automake-mode.

2015-04-03  Werner LEMBERG  <wl@gnu.org>

	* chem.man: Make it work in compatibility mode.
	(EL): Fix typo.

2014-09-25  Bernd Warken  <bernd.warken@web.de>

	* chem.pl: New chem version 1.0.5.

	* Makefile.sub: Add .PHONY.  Restructure install and uninstall.

2014-09-03  Bernd Warken  <bernd.warken@web.de>

	* chem.pl: New chem version 1.0.4.  Change version().

	* all `chem' source files: Add and improve the copying
	information.  Remove last update. Add Emacs setting if necessary.

2014-07-05  Bernd Warken  <bernd.warken@web.de>
	________________________________________________________________
	* chem.pl: New chem version 1.0.3

	* chem.man: Make file doclifter compatible.

2014-07-04  Bernd Warken  <bernd.warken@web.de>
	________________________________________________________________
	* release of chem 1.0.2

	* chem.man: Remove definition of `.FONT'.

2014-07-04  Bernd Warken  <bernd.warken@web.de>

	* chem.man: Transform into classical man-page style.

2014-07-04  Bernd Warken  <bernd.warken@web.de>

	* chem.man: Remove definition of .Env-var.

2014-07-03  Bernd Warken  <bernd.warken@web.de>
	________________________________________________________________
	* release of chem 1.0.1

	* chem.man: Add `.mso' for `groffer.man'.

2014-06-17  Bernd Warken  <bernd.warken@web.de>
	________________________________________________________________
	* release of chem 1.0.0

	* Makefile.sub: Add Emacs final part.

	* ChangeLog: Correct the space characters in this file as Emacs
	style.

2014-03-29  Steffen Nurpmeso  <sdaoden@yandex.com>

	* Makefile.sub (uninstall_examples): Remove superfluous `rmdir'.

2014-03-29  Steffen Nurpmeso  <sdaoden@yandex.com>

	* Makefile.sub (install_examples): Use `find', not shell globs.

	Instead of using rm(1) two times with shell globs the expansion of
	which will include subdirectories (thus resulting in error
	messages), use find(1) and its `-exec' operand.

2014-03-29  Steffen Nurpmeso  <sdaoden@yandex.com>

	* Makefile.sub: Handle examples separately, controlled by
	$(make{_,_install_,_uninstall_}examples).

2013-01-29  Bernd Warken  <bernd.warken@web.de>

	* all: Change license into GPL2.

2013-01-29  Werner LEMBERG  <wl@gnu.org>

	* Makefile.sub (MOSTLYCLEANADD): Fix typo.

2010-12-13  Werner LEMBERG  <wl@gnu.org>

	Really fix handling of examples/122.

	* examples/122/README: Renamed to...
	* examples/122/README.txt: This.

	* Makefile.sub (all, MOSTLYCLEANADD): Add `examples/122/README'.
	(examples/122/README): New target.
	(install_data): Fix typo.

2010-06-02  Larry Jones  <lawrence.jones@siemens.com>

	* Makefile.sub (install): Fix handling of examples/122.
	It tried to process the CVS subdirectory as a file.

2009-01-03  Werner LEMBERG  <wl@gnu.org>

	* chem.pl: Prepare for groff version 1.20.

2008-01-04  Werner LEMBERG  <wl@gnu.org>

	* chem.man: Insert `\:' in URLs where appropriate.

2007-02-06  Eric S. Raymond  <esr@snark.thyrsus.com>

	* chem.man: Change .UR/.UE and .MT/.ME so the start macro no
	longer takes a second argument that is pasted to the end of the
	generated text.  Instead, the end macro takes an argument that
	does the same thing.

2007-02-02  Werner LEMBERG  <wl@gnu.org>

	* chem.man: Further refinements and normalizations.

2007-02-02  Eric S. Raymond  <esr@snark.thyrsus.com>

	* chem.man: Converted to use .SY/.OP/.YS and for cross-viewer
	portability.  Conversion checked using the protocol described in
	tmac/TESTING-HINTS.

2006-11-10  Bernd Warken  <groff-bernd.warken-72@web.de>
	________________________________________________________________
	* release of chem 0.3.1

	* chem.man: Add information about example files.

2006-11-10  Werner LEMBERG  <wl@gnu.org>

	* chem.man1: Rename back to...
	* chem.man: This.
	Use @G@, @MACRODIR@, and @DATASUBDIR@.

	* Makefile.sub (CLEANADD, all): Don't handle chem.man.
	(chem.man): Remove rule.
	(chem): s/tmacdir/MACRODIR/, s/picdir/PICDIR/.

	* chem.pl: s/tmacdir/MACRODIR/, s/picdir/PICDIR/.

2006-11-10  Bernd Warken  <groff-bernd.warken-72@web.de>
	________________________________________________________________
	* release of chem 0.3.0

	* chem.man1: Rename `chem.man' to translate some `@...@'
	constructs.  Some minor corrections.  Remove some unused macros.

	* examples/README.txt, examples/122/README: Add information on
	`roff2*' programs.

	* chem.pic: Rename `macros.pic'.

	* Makefile.sub, chem.pl: Replace `macros.pic' by `chem.pic'.

2006-11-09  Werner LEMBERG  <wl@gnu.org>

	* chem.man: Revised.

2006-11-08  Bernd Warken  <groff-bernd.warken-72@web.de>
	________________________________________________________________
	* release of chem 0.2.0

	* pic.tmac: Remove this file.  Use instead the installed pic.tmac
	in $(tmacdir).

	* Makefile.sub, chem.pl:
	- Install macros.pic to $(tmacdir)/pic/chem.pic.
	- Remove parts with `libdir'.

2006-11-07  Werner LEMBERG  <wl@gnu.org>

	* Makefile.sub: Add and fix $(srcdir) where necessary to make it
	compile with srcdir != builddir.  Other minor fixes improvements.

2006-11-07  Bernd Warken  <groff-bernd.warken-72@web.de>
	________________________________________________________________
	* release of chem 0.1.2

	### `chem' works now with all example files (examples/*.chem and
	examples/122/*.chem).

	* examples/122/README: Add some information on the example files.

	* examples/122/chAi_poly_vinyl_chloride.chem: Use .ps with
	argument `-2' and recall `.ps +2' at the end of the file.  This
	stops the size shift in the following files.

	* examples/122/ch6b_dna.chem: Make the file runnable, it works
	now.

	* examples/reserpine.chem: Change access to `begin chem'.

	* chem.man:
	- Fix the BUGS section.
	- Correct the name of the macro file to `macros.pic'.
	- Extent section DESCRIPTION and LANGUAGE.
	- Moieties and Strings: Rewritten section about moieties and
	double quoted strings.

	* chem.pl:
	- parameter check: Add filespecs only when non-empty file.
	- Set $Last_Type to $OTHER for the `pic' command.
	- joinring(), label(), labsave(), reduce(): Remove these functions.
	- `[', `]', `{', `}', `define': Make these and the defined
	functions commands for `chem' without using the `pic' word.
	- @Words: Fix it such that all double quoted strings are
	completely in an element.
	- `Last: ': Remove this prefix from all commands that are related
	to `pic'.

	### global variables

	* chem.pl:
	- $Line: Add this variable to store the unchanged input line.
	- %Params: Add the variables from setparams() to this hash.
	- %Types: Add BOND, MOL, RING, OTHER from init() to this hash.
	- %Put: Move %put to this.
	- %Dbl: Move %dbl to this.
	- %Labtype: Move %labtype to this.
	- %Aromatic: Move $aromatic to this.
	- %Dc: Move %dc to this.
	- %Nput: Move $nput to this.
	- %Define: New hash for storing the names of the `define'
	constructs during `chem'.  Use the elements in `%Define' as `chem'
	commands.

2006-10-27  Bernd Warken  <groff-bernd.warken-72@web.de>
	________________________________________________________________
	* release of chem 0.1.1

	* chem.pl:
	- Add handling of `[' and `]' (extension of chem awk).
	- Restrict line break after labels.

	* ChangeLog: Correct the former entry.

2006-10-26  Bernd Warken  <groff-bernd.warken-72@web.de>
	________________________________________________________________
	* release of chem 0.1.0

	### Extensions to the chem awk version.

	* chem.pl:
	- parameters: -h, --help, -v, --version, -- are added as options.
	The minus character - is added as filespec for standard input, it
	may be used several times.
	- remove the functions `inline', `shiftfields', and `set'.
	- Fix the handling of the initialization commands .PS, .cstart,
	`begin chem', and `end'.
	- Add error massages.
	- error(): Add file name.
	- Add concatenation of lines with final backslash `\'.
	- Add pic.tmac to guarantee that each pic display is centered.
	- Warnings and strict are active.

	### Source files of the chem Perl version

	* chem.pl: Source file for the Perl version of chem.

	* macros.pic: Pic macro file that is loaded by each run of chem.

	* pic.tmac: Macro file for .PS and .PE; taken over from the groff
	source file <groff-top-source>/tmac/pic.tmac.

	* Makefile.sub: Make file for the groff system.

	* ChangeLog: This file.

	* chem.man: Manual page for the Perl version of chem.

	* README.txt: File for information on this chem version.

	* examples/*.chem: Self-constructed example files for chem.

	* examples/README.txt: Information on the example files.

	* examples/122/*.chem: Example files from the classical chem book
	122.ps at <http://cm.bell-labs.com/cm/cs/cstr/122.ps.gz>.

	* examples/122/README: Information on the example files in this
	directory.

2006-10-16  Bernd Warken  <groff-bernd.warken-72@web.de>

	* awk version of chem
	chem is a roff preprocessor that generates chemical structure
	diagrams suitable for the pic preprocessor.  The original version
	of chem is an awk script written by Brian Kernighan.  This project
	is a rewrite of chem in Perl.

________________________________________________________________________

Copyright 2006-2015 Free Software Foundation, Inc.
Copyright 2022-2024 G. Branden Robinson

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.

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