local getArgs = require('Module:Arguments').getArgs local p = {} -- module's table  local am = {} -- Elements with wiki links am.H="[[Hydrogen|H]]";am.He="[[Helium|He]]"; am.Li="[[Lithium|Li]]";am.Be="[[Beryllium|Be]]";am.B="[[Boron|B]]";am.C="[[Carbon|C]]";am.N="[[Nitrogen|N]]";am.O="[[Oxygen|O]]";am.F="[[Fluorine|F]]";am.Ne="[[Neon|Ne]]"; am.Na="[[Sodium|Na]]";am.Mg="[[Magnesium|Mg]]";am.Al="[[Aluminium |Al]]";am.Si="[[Silicon|Si]]";am.P="[[Phosphorus|P]]";am.S="[[Sulfur|S]]";am.Cl="[[Chlorine|Cl]]";am.Ar="[[Argon|Ar]]"; am.K="[[Potassium|K]]";am.Ca="[[Calcium|Ca]]";am.Sc="[[Scandium|Sc]]";am.Ti="[[Titanium|Ti]]";am.V="[[Vanadium|V]]";am.Cr="[[Chromium|Cr]]";am.Mn="[[Manganese|Mn]]";am.Fe="[[Iron|Fe]]";am.Co="[[Cobalt|Co]]";am.Ni="[[Nickel|Ni]]";am.Cu="[[Copper|Cu]]";am.Zn="[[Zinc|Zn]]";am.Ga="[[Gallium|Ga]]";am.Ge="[[Germanium|Ge]]";am.As="[[Arsenic|As]]";am.Se="[[Selenium|Se]]";am.Br="[[Bromine|Br]]";am.Kr="[[Krypton|Kr]]";am.Rb="[[Rubidium|Rb]]"; am.Sr="[[Strontium|Sr]]";am.Y="[[Yttrium|Y]]";am.Zr="[[Zirconium|Zr]]";am.Nb="[[Niobium|Nb]]";am.Mo="[[Molybdenum|Mo]]";am.Tc="[[Technetium|Tc]]";am.Ru="[[Ruthenium|Ru]]";am.Rh="[[Rhodium|Rh]]";am.Pd="[[Palladium|Pd]]";am.Ag="[[Silver|Ag]]";am.Cd="[[Cadmium|Cd]]";am.In="[[Indium|In]]";am.Sn="[[Tin|Sn]]";am.Sb="[[Antimony|Sb]]";am.Te="[[Tellurium|Te]]";am.I="[[Iodine|I]]";am.Xe="[[Xenon|Xe]]"; am.Cs="[[Caesium|Cs]]";am.Ba="[[Barium|Ba]]";am.La="[[Lanthanum|La]]";am.Ce="[[Cerium|Ce]]";am.Pr="[[Praseodymium|Pr]]";am.Nd="[[Neodymium|Nd]]";am.Pm="[[Promethium|Pm]]";am.Sm="[[Samarium|Sm]]";am.Eu="[[Europium|Eu]]";am.Gd="[[Gadolinium|Gd]]";am.Tb="[[Terbium|Tb]]";am.Dy="[[Dysprosium|Dy]]";am.Ho="[[Holmium|Ho]]";am.Er="[[Erbium|Er]]";am.Tm="[[Thulium|Tm]]";am.Yb="[[Ytterbium|Yb]]";am.Lu="[[Lutetium|Lu]]";am.Hf="[[Hafnium|Hf]]";am.Ta="[[Tantalum|Ta]]";am.W="[[Tungsten|W]]";am.Re="[[Rhenium|Re]]";am.Os="[[Osmium|Os]]";am.Ir="[[Iridium|Ir]]";am.Pt="[[Platinum|Pt]]";am.Au="[[Gold|Au]]";am.Hg="[[Mercury (element)|Hg]]";am.Tl="[[Thallium|Tl]]";am.Pb="[[Lead|Pb]]";am.Bi="[[Bismuth|Bi]]";am.Po="[[Polonium|Po]]";am.At="[[Astatine|At]]";am.Rn="[[Radon|Rn]]"; am.Fr="[[Francium|Fr]]";am.Ra="[[Radium|Ra]]";am.Ac="[[Actinium|Ac]]";am.Th="[[Thorium|Th]]";am.Pa="[[Protactinium|Pa]]";am.U="[[Uranium|U]]";am.Np="[[Neptunium|Np]]";am.Pu="[[Plutonium|Pu]]";am.Am="[[Americium|Am]]";am.Cm="[[Curium|Cm]]";am.Bk="[[Berkelium|Bk]]";am.Cf="[[Californium|Cf]]";am.Es="[[Einsteinium|Es]]";am.Fm="[[Fermium|Fm]]";am.Md="[[Mendelevium|Md]]";am.No="[[Nobelium|No]]";am.Lr="[[Lawrencium|Lr]]";am.Rf="[[Rutherfordium|Rf]]";am.Db="[[Dubnium|Db]]";am.Sg="[[Seaborgium|Sg]]";am.Bh="[[Bohrium|Bh]]";am.Hs="[[Hassium|Hs]]";am.Mt="[[Meitnerium|Mt]]";am.Ds="[[Darmstadtium|Ds]]";am.Rg="[[Roentgenium|Rg]]";am.Cp="[[Copernicium|Cp]]";am.Nh="[[Nihonium|Nh]]";am.Fl="[[Flerovium|Fl]]";am.Mc="[[Moscovium|Mc]]";am.Lv="[[Livermorium|Lv]]";am.Ts="[[Tennessine|Ts]]";am.Og="[[Oganesson|Og]]";  local T_ELEM = 0 -- token types local T_NUM = 1 -- number local T_OPEN = 2 -- open '(' local T_CLOSE = 3 -- close ')' local T_PM_CHARGE = 4 -- + or – local T_WATER = 6 -- .xH2O x number local T_CRYSTAL = 9 -- .x local T_CHARGE = 8 -- charge (x+), (x-) local T_SUF_CHARGE = 10 -- suffix and charge e.g. 2+ from H2+ local T_SUF_CHARGE2 = 12 -- suffix and (charge) e.g. 2(2+) from He2(2+) local T_SPECIAL = 14 -- starting with \ e.g. \d for double bond (=) local T_SPECIAL2 = 16 -- starting with \y{x} e.g. \i{12} for isotope with mass number 12 local T_ARROW_R = 17 -- match: -> local T_ARROW_EQ = 18 -- match: <-> local T_UNDERSCORE = 19 -- _{ ... } local T_CARET = 20 -- ^{ ... } local T_NOCHANGE = 30 -- Anything else like ☃  function su(up, down) -- like template:su  if (down == "") then  return "<span style=\"display:inline-block; margin-bottom:-0.3em; vertical-align:0.8em; line-height:1.2em; font-size:70%; text-align:left;\">" .. up .. "<br /></span>";  else  return "<span style=\"display:inline-block; margin-bottom:-0.3em; vertical-align:-0.4em; line-height:1.2em; font-size:70%; text-align:left;\">" .. up .. "<br />" .. down .. "</span>";  end end  function DotIt()  return '&nbsp;<span style="font-weight:bold;">&middot;</span>&#32;' end   function item(f) -- (iterator) returns one token (type, value) at a time from the formula 'f'  local i = 1  local first = "true";   return function ()  local t, x = nil, nil   if (first == "true" and f:match('^[0-9]', i)) then  x = f:match('^[%d.]+', i); t = T_NOCHANGE; i = i + x:len(); -- matching coefficient (need a space first)   elseif i <= f:len() then  x = f:match('^%s+[%d.]+', i); t = T_NOCHANGE; -- matching coefficient (need a space first)  if not x then x = f:match('^%s[+]', i); t = T_NOCHANGE; end -- matching + (H2O + H2O)  if not x then x = f:match('^%&%#[%w%d]+%;', i); t = T_NOCHANGE; end -- &#...;  if not x then x = f:match('^%<%-%>', i); t = T_ARROW_EQ; end -- matching <->  if not x then x = f:match('^%-%>', i); t = T_ARROW_R; end -- matching ->  if not x then x = f:match('^%u%l*', i); t = T_ELEM; end -- matching symbols like Aaaaa  if not x then x = f:match('^%d+[+-]', i); t = T_SUF_CHARGE; end -- matching x+, x-  if not x then x = f:match('^%d+%(%d*[+-]%)', i); t = T_SUF_CHARGE2; end -- matching x(y+/-), x(+/-)  if not x then x = f:match('^%(%d*[+-]%)', i); t = T_CHARGE; end -- matching (x+) (xx+), (x-) (xx-)  if not x then x = f:match('^[%d.]+', i); t = T_NUM; end -- matching number  if not x then x = f:match('^[(|{|%[]', i); t = T_OPEN; end -- matching ({[  if not x then x = f:match('^[)|}|%]]', i); t = T_CLOSE; end -- matching )}]  if not x then x = f:match('^[+-]', i); t = T_PM_CHARGE; end -- matching + or -  if not x then x = f:match('^%*[%d.]*H2O', i); t = T_WATER; end -- Crystal water  if not x then x = f:match('^%*[%d.]*', i); t = T_CRYSTAL; end -- Crystal  if not x then x = f:match('^[\\].{%d+}', i); t = T_SPECIAL2; end -- \y{x}  if not x then x = f:match('^[\\].', i); t = T_SPECIAL; end -- \x  if not x then x = f:match('^_{[^}]*}', i); t = T_UNDERSCORE; end -- _{...}  if not x then x = f:match('^\^{[^}]*}', i); t = T_CARET; end -- ^{...}  if not x then x = f:match('^.', i); t = T_NOCHANGE; end --the rest - one by one  if x then i = i + x:len(); else i = i + 999; error("Invalid character in formula!!!!!!! : "..f) end  end  first = "false"  return t, x  end  end  function p._chem(args)  local f = args[1] or ''   f = string.gsub(f, "–", "-") -- replace – with -  f = string.gsub(f, "−", "-") -- replace – with -   local sumO = 0  local formula = ''  local t, x   local link = args['link'] or ""  local auto = args['auto'] or ""   if not (link == '') then formula = formula .. "[[" .. link .. "|"; end -- wikilink start [[link|   for t, x in item(f) do  if t == T_ELEM then if (auto == '') then formula = formula .. x elseif am[x] then formula = formula .. am[x]; am[x] = x else formula = formula .. x end  elseif t == T_COEFFICIENT then formula = formula .. x  elseif t == T_NUM then formula = formula .. su("", x);  elseif t == T_OPEN then formula = formula .. x; sumO = sumO + 1; -- ( {  elseif t == T_CLOSE then formula = formula .. x; sumO = sumO -1; -- ) }  elseif t == T_PM_CHARGE then formula = formula .. su(string.gsub(x, "-", "−"), "");  elseif t == T_SUF_CHARGE then  formula = formula .. su(string.gsub(string.match(x, "[+-]"), "-", "−"), string.match(x, "%d+"), "");  elseif t == T_SUF_CHARGE2 then  formula = formula .. su(string.sub(string.gsub(string.match(x, "%(%d*[+-]"), "-", "−"), 2, -1), string.match(x, "%d+"))   elseif t == T_CHARGE then formula = formula .. "<sup>"; if string.match(x, "%d+") then formula = formula .. string.match(x, "%d+"); end formula = formula .. string.gsub(string.match(x, "[%+-]"), "-", "−") .. "</sup>"; -- can not concatenat a nil value from string.match(x, "%d+");   elseif t == T_CRYSTAL then formula = formula .. DotIt() .. string.gsub( x, "*", ' ', 1 );   elseif t == T_SPECIAL then  parameter = string.sub(x, 2, 2) -- x fra \x   if parameter == "s" then formula = formula .. "–" -- single bond  elseif parameter == "d" then formula = formula .. "=" -- double bond  elseif parameter == "t" then formula = formula .. "≡" -- tripple bond  elseif parameter == "q" then formula = formula .. "≣" -- Quadruple bond  elseif parameter == "h" then formula = formula .. "η" -- η, hapticity  elseif parameter == "-" then formula = formula .. "-" -- -  elseif parameter == "\\" then formula = formula .. "\\" -- \  elseif parameter == "\'" then formula = formula .. "&#39;" -- html-code for '  end  elseif t == T_SPECIAL2 then -- \y{x}  parameter = string.sub(x, 2, 2) -- y fra \y{x}   if parameter == "h" then --[[Hapticity]]  if (auto == '') then formula = formula .. "η<sup>" .. string.match(x, '%d+') .. "</sup>−"  else  formula = formula .. "[[Hapticity|η<sup>" .. string.match(x, '%d+') .. "</sup>]]−"  end -- elseif parameter == "i" then formula = formula .. su(string.match(x, '%d+'), "") -- [[isotope]]  elseif parameter == "m" then formula = formula .. "μ<sup>" .. string.match(x, '%d+') .. "</sup>−" -- mu ([[bridging ligand]])  end  elseif t == T_WATER then  if string.match(x, "^%*[%d.]") then  formula = formula .. DotIt() .. string.match(x, "%f[%.%d]%d*%.?%d*%f[^%.%d%]]") .. "H<sub>2</sub>O";  else  formula = formula .. DotIt() .. "H<sub>2</sub>O";  end  -- not (auto == nil or auto == '') then formula = formula .. DotIt ..  -- "[[Water of crystallization|H<sub>2</sub>O]]"; -- else -- formula = formula ..  -- DotIt .. "H<sub>2</sub>O"; ---- xxx brug af sub til tal -- end   elseif t == T_UNDERSCORE then formula = formula .. su("", string.sub(x,3,-2)) -- x contains _{string}  elseif t == T_CARET then formula = formula .. su(string.sub(x,3,-2), "") -- x contains ^{string}   elseif t == T_ARROW_R then formula = formula .. " → "  elseif t == T_ARROW_EQ then formula = formula .. " ⇌ "   elseif t == T_NOCHANGE then formula = formula .. x; -- The rest - everything which isn't captured by the regular expresions. E.g. wikilinks and pipes   else error('unreachable - ???') end -- in fact, unreachable  end  -- Removed: Gives false positive for wikilinks, like {{chem2|[[Nitrogen|N]]}}. -- if sumO > 0 then formula = formula .. "<span style=\"display:none;font-size:100%\" class=\"error citation-comment\"> Too many (</span>;" -- elseif sumO < 0 then formula = formula .. "'<span style=\"display:none;font-size:100%\" class=\"error citation-comment\"> Too many )</span>;" -- end   if not (link == nil or link == '') then formula = formula .. "]]"; end -- wikilink closing ]]   return formula end  function p.chem(frame)  local args = getArgs(frame)  return p._chem(args) end  return p