elemcvt.sh - units - Git - code.swisschili.sh

 #! /bin/sh
 # ******************************************************************************
 #  elemcvt: convert NIST "Linear ASCII" table of elements to units(1) format
 #  Usage: elemcvt [options] [<file>]
 #  Author: Jeff Conrad
 #  Date:  2024-01-06
 # ******************************************************************************

 # Adjust PATH to suit.
 # For Windows w/MKS Toolkit, this assumes /bin is a symbolic link to
 # $ROOTDIR/mksnt.

 PATH=/bin

 progname=${0##*[/\\]}
 progname=${progname%.sh}
 export TITLEBAR=$progname

 umsg="Usage: $progname [options] [file]
 Options:
   -d  Show elements for which no standard atomic mass is given and exit
   -v  Verbose"

 show_no_std_atomic_mass=	# show elements for which no std atomic mass is given
 verbose=
 errors=
 DUALCASE=1	# used in MKS Toolkit to make options case sensitive

 while getopts :dv arg
 do
     case $arg in
     d)
 	show_no_std_atomic_mass=YES ;;
     v)
 	verbose=YES ;;
     :)
 	# OPTARG contains the option missing the argument
 	print -ru2 -- "$progname: option $OPTARG requires an argument"
 	errors=YES
 	;;
     [?])
 	# OPTARG contains the invalid option
 	print -ru2 -- "$progname: unknown option $OPTARG"
 	errors=YES
 	;;
     esac
 done
 shift $((OPTIND - 1))
 unset DUALCASE

 if [ -n "$errors" ]
 then
     print -ru2 -- "$umsg"
     exit 1
 fi

 awk '

 function show_element_info(atomic_number, atomic_symbol, std_atomic_mass_str)
 {
     printf("# %s: %s (%d)", names[atomic_number], atomic_symbol, atomic_number)
     if (std_atomic_mass_str)
 	printf("  std atomic weight: %s", std_atomic_mass_str)
     print ""
 }

 # <name>_<atomic num>  <mass> # <mole fraction>
 function show_isotope(name, num)
 {
     printf("%-*s%*s%*.*f", max_isotope_len, sprintf("%s_%d", name, num),
 	    sepwid, " ", isoprecis + 4, isoprecis, mass[num])
     if (composition[num])
 	printf("   # %.*f", compprecis, composition[num])
     print ""
 }

 function show_element_name(name)
 {
     printf("%-*s%*s", max_name_len, name, sepwid, " ")
 }

 # <mole fraction> <name>_<mass num>
 function mole_fraction(atomic_number, names, mass_num,  mass_wid)
 {
     if (composition[mass_num] == 1) {
 	mass_wid = length(int(mass_number[n_isotopes]))
 	# align with 1st digit of atomic mass
 	printf("%*s%s_%d", sepwid + 2 - mass_wid, " ", names[atomic_number], mass_num)
     }
     else
 	printf("%.*f %s_%d", compprecis, composition[mass_num],
 		names[atomic_number], mass_num)
 }

 # add line continuation and '+' sign
 function add_continuation()
 {
     printf(" \\\n")
     printf("%-*s+ ", max_name_len + sepwid - 2, " ")
 }

 # <name>_<mass num> # most stable
 function use_most_stable(atomic_number, mass,  mass_wid)
 {
     mass_wid = length(int(mass_number[n_isotopes]))
     printf("%*s%-*s   # most stable", sepwid + 2 - mass_wid, " ",
 	    isoprecis + 1 + mass_wid, sprintf("%s_%d", names[atomic_number], mass))
 }

 # <name>_<mass num> # standard atomic mass
 function use_std_mass(atomic_number, mass,  mass_wid)
 {
     mass_wid = length(int(mass_number[n_isotopes]))
     printf("%*s%-*s   # standard atomic mass", sepwid + 2 - mass_wid, " ",
 	    isoprecis + 1 + mass_wid, sprintf("%s_%d", names[atomic_number], mass))
 }

 # show isotopes and the sum of mole fraction-mass products
 function show_element_data(atomic_number, names)
 {
     # isotopes and relative abundances
     for (ndx = 1; ndx <= n_isotopes; ndx++) {
 	mass_num = mass_number[ndx]
 	show_isotope(names[atomic_number], mass_num)
     }

     # show a value for atomic mass if one of these is available;
     # otherwise, show only isotope masses.
     if (total_composition > 0 || most_stable_mass || std_atomic_mass)
 	show_element = 1
     else
 	show_element = 0

     # atomic mass: sum of mole fraction-mass products
     # element name
     if (show_element)
 	show_element_name(names[atomic_number])

     mass_num = mass_number[1]
     firstval = 0

     # first isotope
     if (composition[mass_num] > 0) {
 	mole_fraction(atomic_number, names, mass_num)
 	firstval = 1
     }
     if (n_isotopes > 1) {
 	for (ndx = 2; ndx < n_isotopes; ndx++) {
 	    mass_num = mass_number[ndx]
 	    if (composition[mass_num] > 0) {
 		if (firstval == 1)
 		    add_continuation()
 		mole_fraction(atomic_number, names, mass_num)
 		firstval = 1
 	    }
 	}
 	# last isotope
 	mass_num = mass_number[n_isotopes]
 	if (composition[mass_num] > 0) {
 	    if (firstval == 1)
 		add_continuation()
 	    mole_fraction(atomic_number, names, mass_num)
 	    print ""
 	}
     }
     else
 	print ""

     # options if mole fraction is not given for any isotope
     if (total_composition == 0) {
 	if (most_stable_mass)
 	    use_most_stable(atomic_number, most_stable_mass)
 	else if (std_atomic_mass)
 	    use_std_mass(atomic_number, std_atomic_mass)
     }

     if (! composition[mass_number[n_isotopes]])
 	print ""
 }

 function output(atomic_number)
 {
     sepwid = 5		# width of column separation
     compprecis = 8	# for mole fraction
     isoprecis = 10	# for isotope mass

     # NIST show H, D, and T
     if (atomic_number == 1)
 	atomic_symbol = "H"

     show_element_info(atomic_number, atomic_symbol, std_atomic_mass_str)

     if (am_names[atomic_number])
 	print "# IUPAC spelling"

     show_element_data(atomic_number, names)

     # show American spelling if different from IUPAC
     if (am_names[atomic_number]) {
 	print "# American spelling"
 	show_element_data(atomic_number, am_names)
     }
     if (show_element)
 	print ""	# blank line between elements

     most_stable_mass = 0
     total_composition = 0
 }

 function gnu_notes()
 {
     print "\
 # This file is the elements database for use with GNU units, a units\n\
 # conversion program by Adrian Mariano adrianm@gnu.org\n\
 #\n\
 # January 2024 Version 1.0\n\
 #\n\
 # Copyright (C) 2024\n\
 # Free Software Foundation, Inc\n\
 #\n\
 # This program is free software; you can redistribute it and/or modify\n\
 # it under the terms of the GNU General Public License as published by\n\
 # the Free Software Foundation; either version 3 of the License, or\n\
 # (at your option) any later version.\n\
 #\n\
 # This data is distributed in the hope that it will be useful,\n\
 # but WITHOUT ANY WARRANTY; without even the implied warranty of\n\
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n\
 # GNU General Public License for more details.\n\
 #\n\
 # You should have received a copy of the GNU General Public License\n\
 # along with this program; if not, write to the Free Software\n\
 # Foundation, Inc., 51 Franklin Street, Fifth Floor,\n\
 # Boston, MA  02110-1301  USA\n"
 }

 function nist_notes()
 {
     print "# From https://www.nist.gov/pml/atomic-weights-and-isotopic-compositions-relative-atomic-masses\n"

     # notes from https://www.nist.gov/pml/atomic-weights-and-isotopic-compositions-column-descriptions
     print "\
 #   For several elements, the standard atomic weight A_r is given as an\n\
 #   atomic-weight interval with the symbol [a,b] to denote the set of\n\
 #   atomic-weight values in normal materials; thus, [a <= A_r(E) <= b].\n\
 #   The symbols a and b denote the lower and upper bounds of the\n\
 #   interval [a,b], respectively.  The values in parentheses, following\n\
 #   the last significant digit to which they are attributed, are\n\
 #   uncertainties.\n\
 #\n\
 #   Brackets [ ] enclosing a single value indicate the mass number of\n\
 #   the most stable isotope.  For radioactive elements with atomic\n\
 #   numbers 95 or greater, the mass number of the most stable isotope is\n\
 #   not specified, as the list of studied isotopes is still\n\
 #   incomplete.\n"
 }

 function units_notes()
 {
     print "\
 # When composition mole fractions of isotopes are given, the atomic mass\n\
 # of an element is given as the sum of the product(s) of mole\n\
 # fraction(s) and the atomic masses of the relevant isotopes.  When composition\n\
 # mole fractions are not given, the atomic mass is given as\n\
 #\n\
 #   * the mass of the most stable isotope, if available, or\n\
 #   * the standard atomic mass of the element, if available.\n\
 #\n\
 # If neither the most stable isotope nore a standard atomic mass is\n\
 # available, no atomic mass for the element is given; the user must\n\
 # select the isotope most suitable for their purposes.\n\
 #\n\
 # If the standard atomic mass is a range, the value given is the\n\
 # midpoint of that range, which may differ from the value determined\n\
 # from the sum of the products of composition mole fraction and isotope\n\
 # atomic mass.\n"
 }

 BEGIN {
     FS = " *= *"
     show_no_std_atomic_mass = "'"$show_no_std_atomic_mass"'"
     verbose = "'"$verbose"'"
     console = "/dev/console"

     # IUPAC spellings
     names[1] = "hydrogen"
     names[2] = "helium"
     names[3] = "lithium"
     names[4] = "beryllium"
     names[5] = "boron"
     names[6] = "carbon"
     names[7] = "nitrogen"
     names[8] = "oxygen"
     names[9] = "fluorine"
     names[10] = "neon"
     names[11] = "sodium"
     names[12] = "magnesium"
     names[13] = "aluminium"
     names[14] = "silicon"
     names[15] = "phosphorus"
     names[16] = "sulfur"
     names[17] = "chlorine"
     names[18] = "argon"
     names[19] = "potassium"
     names[20] = "calcium"
     names[21] = "scandium"
     names[22] = "titanium"
     names[23] = "vanadium"
     names[24] = "chromium"
     names[25] = "manganese"
     names[26] = "iron"
     names[27] = "cobalt"
     names[28] = "nickel"
     names[29] = "copper"
     names[30] = "zinc"
     names[31] = "gallium"
     names[32] = "germanium"
     names[33] = "arsenic"
     names[34] = "selenium"
     names[35] = "bromine"
     names[36] = "krypton"
     names[37] = "rubidium"
     names[38] = "strontium"
     names[39] = "yttrium"
     names[40] = "zirconium"
     names[41] = "niobium"
     names[42] = "molybdenum"
     names[43] = "technetium"
     names[44] = "ruthenium"
     names[45] = "rhodium"
     names[46] = "palladium"
     names[47] = "silver"
     names[48] = "cadmium"
     names[49] = "indium"
     names[50] = "tin"
     names[51] = "antimony"
     names[52] = "tellurium"
     names[53] = "iodine"
     names[54] = "xenon"
     names[55] = "caesium"
     names[56] = "barium"
     names[57] = "lanthanum"
     names[58] = "cerium"
     names[59] = "praseodymium"
     names[60] = "neodymium"
     names[61] = "promethium"
     names[62] = "samarium"
     names[63] = "europium"
     names[64] = "gadolinium"
     names[65] = "terbium"
     names[66] = "dysprosium"
     names[67] = "holmium"
     names[68] = "erbium"
     names[69] = "thulium"
     names[70] = "ytterbium"
     names[71] = "lutetium"
     names[72] = "hafnium"
     names[73] = "tantalum"
     names[74] = "tungsten"
     names[75] = "rhenium"
     names[76] = "osmium"
     names[77] = "iridium"
     names[78] = "platinum"
     names[79] = "gold"
     names[80] = "mercury"
     names[81] = "thallium"
     names[82] = "lead"
     names[83] = "bismuth"
     names[84] = "polonium"
     names[85] = "astatine"
     names[86] = "radon"
     names[87] = "francium"
     names[88] = "radium"
     names[89] = "actinium"
     names[90] = "thorium"
     names[91] = "protactinium"
     names[92] = "uranium"
     names[93] = "neptunium"
     names[94] = "plutonium"
     names[95] = "americium"
     names[96] = "curium"
     names[97] = "berkelium"
     names[98] = "californium"
     names[99] = "einsteinium"
     names[100] = "fermium"
     names[101] = "mendelevium"
     names[102] = "nobelium"
     names[103] = "lawrencium"
     names[104] = "rutherfordium"
     names[105] = "dubnium"
     names[106] = "seaborgium"
     names[107] = "bohrium"
     names[108] = "hassium"
     names[109] = "meitnerium"
     names[110] = "darmstadtium"
     names[111] = "roentgenium"
     names[112] = "copernicium"
     names[113] = "nihonium"
     names[114] = "flerovium"
     names[115] = "moscovium"
     names[116] = "livermorium"
     names[117] = "tennessine"
     names[118] = "oganesson"

     # American spellings
     am_names[13] = "aluminum"
     am_names[55] = "cesium"

     max_name_len = 0		# length of longest element name
     for (i = 1; i <= 118; i++) {
 	len = length(names[i])
 	if (len > max_name_len) {
 	    max_name_len = len;
 	    longestname = names[i]
 	}
     }
     max_isotope_len = max_name_len + 4	# allow for "_xxx" suffix

     if (! show_no_std_atomic_mass) {
 	gnu_notes()
 	nist_notes()
 	units_notes()
     }

     if (verbose)
 	printf("Longest element name: %s (%d)\n\n", longestname, max_name_len)

     n_isotopes = 0
     mass_number[1] = 0
 }

 # begin file processing

 # skip JavaScript and HTML before data
 NR == 1, $0 ~ /<pre/ { next }
 # skip HTML after data
 $0 ~ /<\/pre>/ { exit }

 # remove trailing space and unpaddable spaces
 {
   gsub(/&nbsp;/, "")
   gsub(/ +$/, "")
 }

 $1 ~ /Atomic Number/ {
     last_atomic_number = atomic_number
     atomic_number = $2 + 0
     if (atomic_number != last_atomic_number && atomic_number > 1) {
 	if (show_no_std_atomic_mass) {
 	    if (! std_atomic_mass_str)
 		print names[last_atomic_number]
 	}
 	else
 	    output(last_atomic_number)
     }
 }

 $1 ~ /Atomic Symbol/ {
     atomic_symbol = $2
 }

 $1 ~ /Mass Number/ {
     if (atomic_number != last_atomic_number) {
 	for (i = 1; i <= n_isotopes; i++)
 	    delete mass_number[i]
 	n_isotopes = 0
     }
     mass_number[++n_isotopes] = $2
 }

 $1 ~ /Relative Atomic Mass/ {
     atomic_mass = $2
     sub(/\([[:digit:]#]+\)/, "", atomic_mass)
     mass[mass_number[n_isotopes]] = atomic_mass
 }

 $1 ~ /Isotopic Composition/ {
     isotopic_composition = $2
     sub(/\([[:digit:]#]+\)/, "", isotopic_composition)
     composition[mass_number[n_isotopes]] = isotopic_composition
     total_composition += isotopic_composition
 }

 $1 ~ /Standard Atomic Weight/ {
     std_atomic_mass = std_atomic_mass_str = $2
     gsub(/\([^)]+\)/, "", std_atomic_mass)
     gsub(/[][]/, "", std_atomic_mass)
     if (std_atomic_mass ~ /,/) {
 	split(std_atomic_mass, range, /,/)
 	std_atomic_mass = (range[1] + range[2]) / 2
     }
     if (std_atomic_mass_str ~ /\[[[:digit:].]+\]/)
 	most_stable_mass = std_atomic_mass
     last_atomic_number = atomic_number
 }

 END {
     if (show_no_std_atomic_mass) {
 	if (! std_atomic_mass_str)
 	    print names[last_atomic_number]
     }
     else
 	output(last_atomic_number)
 } ' $*
	#! /bin/sh
	# ******************************************************************************
	# elemcvt: convert NIST "Linear ASCII" table of elements to units(1) format
	# Usage: elemcvt [options] [<file>]
	# Author: Jeff Conrad
	# Date: 2024-01-06
	# ******************************************************************************

	# Adjust PATH to suit.
	# For Windows w/MKS Toolkit, this assumes /bin is a symbolic link to
	# $ROOTDIR/mksnt.

	PATH=/bin

	progname=${0##*[/\\]}
	progname=${progname%.sh}
	export TITLEBAR=$progname

	umsg="Usage: $progname [options] [file]
	Options:
	-d Show elements for which no standard atomic mass is given and exit
	-v Verbose"

	show_no_std_atomic_mass= # show elements for which no std atomic mass is given
	verbose=
	errors=
	DUALCASE=1 # used in MKS Toolkit to make options case sensitive

	while getopts :dv arg
	do
	case $arg in
	d)
	show_no_std_atomic_mass=YES ;;
	v)
	verbose=YES ;;
	:)
	# OPTARG contains the option missing the argument
	print -ru2 -- "$progname: option $OPTARG requires an argument"
	errors=YES
	;;
	[?])
	# OPTARG contains the invalid option
	print -ru2 -- "$progname: unknown option $OPTARG"
	errors=YES
	;;
	esac
	done
	shift $((OPTIND - 1))
	unset DUALCASE

	if [ -n "$errors" ]
	then
	print -ru2 -- "$umsg"
	exit 1
	fi

	awk '

	function show_element_info(atomic_number, atomic_symbol, std_atomic_mass_str)
	{
	printf("# %s: %s (%d)", names[atomic_number], atomic_symbol, atomic_number)
	if (std_atomic_mass_str)
	printf(" std atomic weight: %s", std_atomic_mass_str)
	print ""
	}

	# <name>_<atomic num> <mass> # <mole fraction>
	function show_isotope(name, num)
	{
	printf("%-s%s%.f", max_isotope_len, sprintf("%s_%d", name, num),
	sepwid, " ", isoprecis + 4, isoprecis, mass[num])
	if (composition[num])
	printf(" # %.*f", compprecis, composition[num])
	print ""
	}

	function show_element_name(name)
	{
	printf("%-s%s", max_name_len, name, sepwid, " ")
	}

	# <mole fraction> <name>_<mass num>
	function mole_fraction(atomic_number, names, mass_num, mass_wid)
	{
	if (composition[mass_num] == 1) {
	mass_wid = length(int(mass_number[n_isotopes]))
	# align with 1st digit of atomic mass
	printf("%*s%s_%d", sepwid + 2 - mass_wid, " ", names[atomic_number], mass_num)
	}
	else
	printf("%.*f %s_%d", compprecis, composition[mass_num],
	names[atomic_number], mass_num)
	}

	# add line continuation and '+' sign
	function add_continuation()
	{
	printf(" \\\n")
	printf("%-*s+ ", max_name_len + sepwid - 2, " ")
	}

	# <name>_<mass num> # most stable
	function use_most_stable(atomic_number, mass, mass_wid)
	{
	mass_wid = length(int(mass_number[n_isotopes]))
	printf("%s%-s # most stable", sepwid + 2 - mass_wid, " ",
	isoprecis + 1 + mass_wid, sprintf("%s_%d", names[atomic_number], mass))
	}

	# <name>_<mass num> # standard atomic mass
	function use_std_mass(atomic_number, mass, mass_wid)
	{
	mass_wid = length(int(mass_number[n_isotopes]))
	printf("%s%-s # standard atomic mass", sepwid + 2 - mass_wid, " ",
	isoprecis + 1 + mass_wid, sprintf("%s_%d", names[atomic_number], mass))
	}

	# show isotopes and the sum of mole fraction-mass products
	function show_element_data(atomic_number, names)
	{
	# isotopes and relative abundances
	for (ndx = 1; ndx <= n_isotopes; ndx++) {
	mass_num = mass_number[ndx]
	show_isotope(names[atomic_number], mass_num)
	}

	# show a value for atomic mass if one of these is available;
	# otherwise, show only isotope masses.
	if (total_composition > 0 \|\| most_stable_mass \|\| std_atomic_mass)
	show_element = 1
	else
	show_element = 0

	# atomic mass: sum of mole fraction-mass products
	# element name
	if (show_element)
	show_element_name(names[atomic_number])

	mass_num = mass_number[1]
	firstval = 0

	# first isotope
	if (composition[mass_num] > 0) {
	mole_fraction(atomic_number, names, mass_num)
	firstval = 1
	}
	if (n_isotopes > 1) {
	for (ndx = 2; ndx < n_isotopes; ndx++) {
	mass_num = mass_number[ndx]
	if (composition[mass_num] > 0) {
	if (firstval == 1)
	add_continuation()
	mole_fraction(atomic_number, names, mass_num)
	firstval = 1
	}
	}
	# last isotope
	mass_num = mass_number[n_isotopes]
	if (composition[mass_num] > 0) {
	if (firstval == 1)
	add_continuation()
	mole_fraction(atomic_number, names, mass_num)
	print ""
	}
	}
	else
	print ""

	# options if mole fraction is not given for any isotope
	if (total_composition == 0) {
	if (most_stable_mass)
	use_most_stable(atomic_number, most_stable_mass)
	else if (std_atomic_mass)
	use_std_mass(atomic_number, std_atomic_mass)
	}

	if (! composition[mass_number[n_isotopes]])
	print ""
	}

	function output(atomic_number)
	{
	sepwid = 5 # width of column separation
	compprecis = 8 # for mole fraction
	isoprecis = 10 # for isotope mass

	# NIST show H, D, and T
	if (atomic_number == 1)
	atomic_symbol = "H"

	show_element_info(atomic_number, atomic_symbol, std_atomic_mass_str)

	if (am_names[atomic_number])
	print "# IUPAC spelling"

	show_element_data(atomic_number, names)

	# show American spelling if different from IUPAC
	if (am_names[atomic_number]) {
	print "# American spelling"
	show_element_data(atomic_number, am_names)
	}
	if (show_element)
	print "" # blank line between elements

	most_stable_mass = 0
	total_composition = 0
	}

	function gnu_notes()
	{
	print "\
	# This file is the elements database for use with GNU units, a units\n\
	# conversion program by Adrian Mariano adrianm@gnu.org\n\
	#\n\
	# January 2024 Version 1.0\n\
	#\n\
	# Copyright (C) 2024\n\
	# Free Software Foundation, Inc\n\
	#\n\
	# This program is free software; you can redistribute it and/or modify\n\
	# it under the terms of the GNU General Public License as published by\n\
	# the Free Software Foundation; either version 3 of the License, or\n\
	# (at your option) any later version.\n\
	#\n\
	# This data is distributed in the hope that it will be useful,\n\
	# but WITHOUT ANY WARRANTY; without even the implied warranty of\n\
	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\n\
	# GNU General Public License for more details.\n\
	#\n\
	# You should have received a copy of the GNU General Public License\n\
	# along with this program; if not, write to the Free Software\n\
	# Foundation, Inc., 51 Franklin Street, Fifth Floor,\n\
	# Boston, MA 02110-1301 USA\n"
	}

	function nist_notes()
	{
	print "# From https://www.nist.gov/pml/atomic-weights-and-isotopic-compositions-relative-atomic-masses\n"

	# notes from https://www.nist.gov/pml/atomic-weights-and-isotopic-compositions-column-descriptions
	print "\
	# For several elements, the standard atomic weight A_r is given as an\n\
	# atomic-weight interval with the symbol [a,b] to denote the set of\n\
	# atomic-weight values in normal materials; thus, [a <= A_r(E) <= b].\n\
	# The symbols a and b denote the lower and upper bounds of the\n\
	# interval [a,b], respectively. The values in parentheses, following\n\
	# the last significant digit to which they are attributed, are\n\
	# uncertainties.\n\
	#\n\
	# Brackets [ ] enclosing a single value indicate the mass number of\n\
	# the most stable isotope. For radioactive elements with atomic\n\
	# numbers 95 or greater, the mass number of the most stable isotope is\n\
	# not specified, as the list of studied isotopes is still\n\
	# incomplete.\n"
	}

	function units_notes()
	{
	print "\
	# When composition mole fractions of isotopes are given, the atomic mass\n\
	# of an element is given as the sum of the product(s) of mole\n\
	# fraction(s) and the atomic masses of the relevant isotopes. When composition\n\
	# mole fractions are not given, the atomic mass is given as\n\
	#\n\
	# * the mass of the most stable isotope, if available, or\n\
	# * the standard atomic mass of the element, if available.\n\
	#\n\
	# If neither the most stable isotope nore a standard atomic mass is\n\
	# available, no atomic mass for the element is given; the user must\n\
	# select the isotope most suitable for their purposes.\n\
	#\n\
	# If the standard atomic mass is a range, the value given is the\n\
	# midpoint of that range, which may differ from the value determined\n\
	# from the sum of the products of composition mole fraction and isotope\n\
	# atomic mass.\n"
	}

	BEGIN {
	FS = " = "
	show_no_std_atomic_mass = "'"$show_no_std_atomic_mass"'"
	verbose = "'"$verbose"'"
	console = "/dev/console"

	# IUPAC spellings
	names[1] = "hydrogen"
	names[2] = "helium"
	names[3] = "lithium"
	names[4] = "beryllium"
	names[5] = "boron"
	names[6] = "carbon"
	names[7] = "nitrogen"
	names[8] = "oxygen"
	names[9] = "fluorine"
	names[10] = "neon"
	names[11] = "sodium"
	names[12] = "magnesium"
	names[13] = "aluminium"
	names[14] = "silicon"
	names[15] = "phosphorus"
	names[16] = "sulfur"
	names[17] = "chlorine"
	names[18] = "argon"
	names[19] = "potassium"
	names[20] = "calcium"
	names[21] = "scandium"
	names[22] = "titanium"
	names[23] = "vanadium"
	names[24] = "chromium"
	names[25] = "manganese"
	names[26] = "iron"
	names[27] = "cobalt"
	names[28] = "nickel"
	names[29] = "copper"
	names[30] = "zinc"
	names[31] = "gallium"
	names[32] = "germanium"
	names[33] = "arsenic"
	names[34] = "selenium"
	names[35] = "bromine"
	names[36] = "krypton"
	names[37] = "rubidium"
	names[38] = "strontium"
	names[39] = "yttrium"
	names[40] = "zirconium"
	names[41] = "niobium"
	names[42] = "molybdenum"
	names[43] = "technetium"
	names[44] = "ruthenium"
	names[45] = "rhodium"
	names[46] = "palladium"
	names[47] = "silver"
	names[48] = "cadmium"
	names[49] = "indium"
	names[50] = "tin"
	names[51] = "antimony"
	names[52] = "tellurium"
	names[53] = "iodine"
	names[54] = "xenon"
	names[55] = "caesium"
	names[56] = "barium"
	names[57] = "lanthanum"
	names[58] = "cerium"
	names[59] = "praseodymium"
	names[60] = "neodymium"
	names[61] = "promethium"
	names[62] = "samarium"
	names[63] = "europium"
	names[64] = "gadolinium"
	names[65] = "terbium"
	names[66] = "dysprosium"
	names[67] = "holmium"
	names[68] = "erbium"
	names[69] = "thulium"
	names[70] = "ytterbium"
	names[71] = "lutetium"
	names[72] = "hafnium"
	names[73] = "tantalum"
	names[74] = "tungsten"
	names[75] = "rhenium"
	names[76] = "osmium"
	names[77] = "iridium"
	names[78] = "platinum"
	names[79] = "gold"
	names[80] = "mercury"
	names[81] = "thallium"
	names[82] = "lead"
	names[83] = "bismuth"
	names[84] = "polonium"
	names[85] = "astatine"
	names[86] = "radon"
	names[87] = "francium"
	names[88] = "radium"
	names[89] = "actinium"
	names[90] = "thorium"
	names[91] = "protactinium"
	names[92] = "uranium"
	names[93] = "neptunium"
	names[94] = "plutonium"
	names[95] = "americium"
	names[96] = "curium"
	names[97] = "berkelium"
	names[98] = "californium"
	names[99] = "einsteinium"
	names[100] = "fermium"
	names[101] = "mendelevium"
	names[102] = "nobelium"
	names[103] = "lawrencium"
	names[104] = "rutherfordium"
	names[105] = "dubnium"
	names[106] = "seaborgium"
	names[107] = "bohrium"
	names[108] = "hassium"
	names[109] = "meitnerium"
	names[110] = "darmstadtium"
	names[111] = "roentgenium"
	names[112] = "copernicium"
	names[113] = "nihonium"
	names[114] = "flerovium"
	names[115] = "moscovium"
	names[116] = "livermorium"
	names[117] = "tennessine"
	names[118] = "oganesson"

	# American spellings
	am_names[13] = "aluminum"
	am_names[55] = "cesium"

	max_name_len = 0 # length of longest element name
	for (i = 1; i <= 118; i++) {
	len = length(names[i])
	if (len > max_name_len) {
	max_name_len = len;
	longestname = names[i]
	}
	}
	max_isotope_len = max_name_len + 4 # allow for "_xxx" suffix

	if (! show_no_std_atomic_mass) {
	gnu_notes()
	nist_notes()
	units_notes()
	}

	if (verbose)
	printf("Longest element name: %s (%d)\n\n", longestname, max_name_len)

	n_isotopes = 0
	mass_number[1] = 0
	}

	# begin file processing

	# skip JavaScript and HTML before data
	NR == 1, $0 ~ /<pre/ { next }
	# skip HTML after data
	$0 ~ /<\/pre>/ { exit }

	# remove trailing space and unpaddable spaces
	{
	gsub(/ /, "")
	gsub(/ +$/, "")
	}

	$1 ~ /Atomic Number/ {
	last_atomic_number = atomic_number
	atomic_number = $2 + 0
	if (atomic_number != last_atomic_number && atomic_number > 1) {
	if (show_no_std_atomic_mass) {
	if (! std_atomic_mass_str)
	print names[last_atomic_number]
	}
	else
	output(last_atomic_number)
	}
	}

	$1 ~ /Atomic Symbol/ {
	atomic_symbol = $2
	}

	$1 ~ /Mass Number/ {
	if (atomic_number != last_atomic_number) {
	for (i = 1; i <= n_isotopes; i++)
	delete mass_number[i]
	n_isotopes = 0
	}
	mass_number[++n_isotopes] = $2
	}

	$1 ~ /Relative Atomic Mass/ {
	atomic_mass = $2
	sub(/\([[:digit:]#]+\)/, "", atomic_mass)
	mass[mass_number[n_isotopes]] = atomic_mass
	}

	$1 ~ /Isotopic Composition/ {
	isotopic_composition = $2
	sub(/\([[:digit:]#]+\)/, "", isotopic_composition)
	composition[mass_number[n_isotopes]] = isotopic_composition
	total_composition += isotopic_composition
	}

	$1 ~ /Standard Atomic Weight/ {
	std_atomic_mass = std_atomic_mass_str = $2
	gsub(/\([^)]+\)/, "", std_atomic_mass)
	gsub(/[][]/, "", std_atomic_mass)
	if (std_atomic_mass ~ /,/) {
	split(std_atomic_mass, range, /,/)
	std_atomic_mass = (range[1] + range[2]) / 2
	}
	if (std_atomic_mass_str ~ /\[[[:digit:].]+\]/)
	most_stable_mass = std_atomic_mass
	last_atomic_number = atomic_number
	}

	END {
	if (show_no_std_atomic_mass) {
	if (! std_atomic_mass_str)
	print names[last_atomic_number]
	}
	else
	output(last_atomic_number)
	} ' $*