/// <summary>
/// Build a version of the chemical formula which includes subscripting and converted chemical names
/// </summary>
/// <param name="Formula">The raw ASCII formula to parse</param>
/// <returns>a unicode string representing the prettified formula</returns>
private string _parseChemicalFormula(string Formula)
{
string FormattedFormula = "";
Regex FormulaExpression = new Regex("(\\d*)([a-zA-Z\\d\\[\\]\\(\\)\\-^#=]+)([ .]*)(.*)");
//borrow a dictionary of elements from structure search
PeriodicTable PT = new PeriodicTable();
while (false == string.IsNullOrEmpty(Formula))
{
GroupCollection FormulaGroups = FormulaExpression.Match(Formula).Groups;
//append prefix numbers without changing them
FormattedFormula = FormattedFormula + FormulaGroups[1];
//iterate through the characters of the current compound from left to right
char[] ChemicalCompound = FormulaGroups[2].ToString().ToCharArray();
for (int i = 0; i < ChemicalCompound.Length; i++)
{
char Letter = ChemicalCompound[i];
//convert numbers to subscript versions of themselves
if ('0' <= Letter && Letter <= '9')
{
ChemicalCompound[i] = (char)(Letter + 0x2050);
}
//determine the proper case for non-element letters
else if (false == PT.ElementExists(Letter.ToString()) && 'A' <= Letter && Letter <= 'Z')
{
char LastLetter = i > 0 ? ChemicalCompound[i - 1] : '\0';
char NextLetter = i < ChemicalCompound.Length - 1 ? ChemicalCompound[i + 1] : '\0';
//if the last letter plus this one lowercased make an element and the next is not already lowered
if (NextLetter != Char.ToLower(NextLetter) && PT.ElementExists("" + LastLetter + Char.ToLower(Letter)))
{
ChemicalCompound[i] = Char.ToLower(Letter);
}
//if this letter plus the next one lowercased make an element
else if (PT.ElementExists("" + Letter + Char.ToLower(NextLetter)))
{
ChemicalCompound[i + 1] = Char.ToLower(NextLetter);
i = i + 1;
}
} //else if( false == PT.ElementExists( Letter.ToString() ) && 'A' <= Letter && Letter <= 'Z' )
} //for( int i = 0; i < ChemicalCompound.Length; i++ )
//append the prettified compound
FormattedFormula = FormattedFormula + new string( ChemicalCompound );
//append trailing characters, with periods converted to big middle dots
FormattedFormula = FormattedFormula + FormulaGroups[3].ToString().Trim().Replace('.', (char)0x25cf);
//move on to the next compoud in the formula
Formula = FormulaGroups[4].ToString();
}//while( false == string.IsNullOrEmpty( Formula ) )
return(FormattedFormula);
} //_parseChemicalFormula
