import Foundation
let pattern = ##"""
(?(DEFINE)
(?# Periodic elements )
(?<Hydrogen>H)
(?<Helium>He)
(?<Lithium>Li)
(?<Beryllium>Be)
(?<Boron>B)
(?<Carbon>C)
(?<Nitrogen>N)
(?<Oxygen>O)
(?<Fluorine>F)
(?<Neon>Ne)
(?<Sodium>Na)
(?<Magnesium>Mg)
(?<Aluminum>Al)
(?<Silicon>Si)
(?<Phosphorus>P)
(?<Sulfur>S)
(?<Chlorine>Cl)
(?<Argon>Ar)
(?<Potassium>K)
(?<Calcium>Ca)
(?<Scandium>Sc)
(?<Titanium>Ti)
(?<Vanadium>V)
(?<Chromium>Cr)
(?<Manganese>Mn)
(?<Iron>Fe)
(?<Cobalt>Co)
(?<Nickel>Ni)
(?<Copper>Cu)
(?<Zinc>Zn)
(?<Gallium>Ga)
(?<Germanium>Ge)
(?<Arsenic>As)
(?<Selenium>Se)
(?<Bromine>Br)
(?<Krypton>Kr)
(?<Rubidium>Rb)
(?<Strontium>Sr)
(?<Yttrium>Y)
(?<Zirconium>Zr)
(?<Niobium>Nb)
(?<Molybdenum>Mo)
(?<Technetium>Tc)
(?<Ruthenium>Ru)
(?<Rhodium>Rh)
(?<Palladium>Pd)
(?<Silver>Ag)
(?<Cadmium>Cd)
(?<Indium>In)
(?<Tin>Sn)
(?<Antimony>Sb)
(?<Tellurium>Te)
(?<Iodine>I)
(?<Xenon>Xe)
(?<Cesium>Cs)
(?<Barium>Ba)
(?<Lanthanum>La)
(?<Cerium>Ce)
(?<Praseodymium>Pr)
(?<Neodymium>Nd)
(?<Promethium>Pm)
(?<Samarium>Sm)
(?<Europium>Eu)
(?<Gadolinium>Gd)
(?<Terbium>Tb)
(?<Dysprosium>Dy)
(?<Holmium>Ho)
(?<Erbium>Er)
(?<Thulium>Tm)
(?<Ytterbium>Yb)
(?<Lutetium>Lu)
(?<Hafnium>Hf)
(?<Tantalum>Ta)
(?<Tungsten>W)
(?<Rhenium>Re)
(?<Osmium>Os)
(?<Iridium>Ir)
(?<Platinum>Pt)
(?<Gold>Au)
(?<Mercury>Hg)
(?<Thallium>Tl)
(?<Lead>Pb)
(?<Bismuth>Bi)
(?<Polonium>Po)
(?<Astatine>At)
(?<Radon>Rn)
(?<Francium>Fr)
(?<Radium>Ra)
(?<Actinium>Ac)
(?<Thorium>Th)
(?<Protactinium>Pa)
(?<Uranium>U)
(?<Neptunium>Np)
(?<Plutonium>Pu)
(?<Americium>Am)
(?<Curium>Cm)
(?<Berkelium>Bk)
(?<Californium>Cf)
(?<Einsteinium>Es)
(?<Fermium>Fm)
(?<Mendelevium>Md)
(?<Nobelium>No)
(?<Lawrencium>Lr)
(?<Rutherfordium>Rf)
(?<Dubnium>Db)
(?<Seaborgium>Sg)
(?<Bohrium>Bh)
(?<Hassium>Hs)
(?<Meitnerium>Mt)
(?<Darmstadtium>Ds)
(?<Roentgenium>Rg)
(?<Copernicium>Cn)
(?<Nihonium>Nh)
(?<Flerovium>Fl)
(?<Moscovium>Mc)
(?<Livermorium>Lv)
(?<Tennessine>Ts)
(?<Oganesson>Og)
(?# Regex )
(?<Element>(?&Actinium)|(?&Silver)|(?&Aluminum)|(?&Americium)|(?&Argon)|(?&Arsenic)|(?&Astatine)|(?&Gold)|(?&Barium)|(?&Beryllium)|(?&Bohrium)|(?&Bismuth)|(?&Berkelium)|(?&Bromine)|(?&Boron)|(?&Calcium)|(?&Cadmium)|(?&Cerium)|(?&Californium)|(?&Chlorine)|(?&Curium)|(?&Copernicium)|(?&Cobalt)|(?&Chromium)|(?&Cesium)|(?&Copper)|(?&Carbon)|(?&Dubnium)|(?&Darmstadtium)|(?&Dysprosium)|(?&Erbium)|(?&Einsteinium)|(?&Europium)|(?&Iron)|(?&Flerovium)|(?&Fermium)|(?&Francium)|(?&Fluorine)|(?&Gallium)|(?&Gadolinium)|(?&Germanium)|(?&Helium)|(?&Hafnium)|(?&Mercury)|(?&Holmium)|(?&Hassium)|(?&Hydrogen)|(?&Indium)|(?&Iridium)|(?&Iodine)|(?&Krypton)|(?&Potassium)|(?&Lanthanum)|(?&Lithium)|(?&Lawrencium)|(?&Lutetium)|(?&Livermorium)|(?&Moscovium)|(?&Mendelevium)|(?&Magnesium)|(?&Manganese)|(?&Molybdenum)|(?&Meitnerium)|(?&Sodium)|(?&Niobium)|(?&Neodymium)|(?&Neon)|(?&Nihonium)|(?&Nickel)|(?&Nobelium)|(?&Neptunium)|(?&Nitrogen)|(?&Oganesson)|(?&Osmium)|(?&Oxygen)|(?&Protactinium)|(?&Lead)|(?&Palladium)|(?&Promethium)|(?&Polonium)|(?&Praseodymium)|(?&Platinum)|(?&Plutonium)|(?&Phosphorus)|(?&Radium)|(?&Rubidium)|(?&Rhenium)|(?&Rutherfordium)|(?&Roentgenium)|(?&Rhodium)|(?&Radon)|(?&Ruthenium)|(?&Antimony)|(?&Scandium)|(?&Selenium)|(?&Seaborgium)|(?&Silicon)|(?&Samarium)|(?&Tin)|(?&Strontium)|(?&Sulfur)|(?&Tantalum)|(?&Terbium)|(?&Technetium)|(?&Tellurium)|(?&Thorium)|(?&Titanium)|(?&Thallium)|(?&Thulium)|(?&Tennessine)|(?&Uranium)|(?&Vanadium)|(?&Tungsten)|(?&Xenon)|(?&Ytterbium)|(?&Yttrium)|(?&Zirconium)|(?&Zinc))
(?<Num>(?:[1-9]\d*)?)
(?<ElementGroup>(?:(?&Element)(?&Num))+)
(?<ElementParenthesesGroup>\((?&ElementGroup)+\)(?&Num))
(?<ElementSquareBracketGroup>\[(?:(?:(?&ElementParenthesesGroup)(?:(?&ElementGroup)|(?&ElementParenthesesGroup))+)|(?:(?:(?&ElementGroup)|(?&ElementParenthesesGroup))+(?&ElementParenthesesGroup)))\](?&Num))
)
^((?<Brackets>(?&ElementSquareBracketGroup))|(?<Parentheses>(?&ElementParenthesesGroup))|(?<Group>(?&ElementGroup)))+$
"""##
let regex = try! NSRegularExpression(pattern: pattern, options: [.anchorsMatchLines, .allowCommentsAndWhitespace])
let testString = #"""
-- These entries are valid --
C
CH
CH3
O2
C2CH2H2
(CH)
(CH3)
(CH3NO4)
(CH3NO4)2
[CH3(NO4)]
[(NO4)CH]2
[(NO4)(CH3)]
(CH3)2CFCOO(CH2)2Si[NO3(CH3)2]2
-- These entries are invalid --
N0
N01
A
c
(CH[NO4])
[(NO4)]
[NO4]
[NO4(CH])
(CH3)2CFCOO(CH2)2Si[NO3(CH3)2]2Cl[N2]
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let matches = regex.matches(in: testString, range: stringRange)
var result: [[String]] = []
for match in matches {
var groups: [String] = []
for rangeIndex in 1 ..< match.numberOfRanges {
let nsRange = match.range(at: rangeIndex)
guard !NSEqualRanges(nsRange, NSMakeRange(NSNotFound, 0)) else { continue }
let string = (testString as NSString).substring(with: nsRange)
groups.append(string)
}
if !groups.isEmpty {
result.append(groups)
}
}
print(result)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Swift 5.2, please visit: https://developer.apple.com/documentation/foundation/nsregularexpression