private void ProcessEscapeSequence(TexFormula formula,
SourceSpan value,
ref int position,
bool allowClosingDelimiter,
ref bool closedDelimiter,
ICommandEnvironment environment)
{
var initialSrcPosition = position;
position++;
var start = position;
while (position < value.Length)
{
var ch = value[position];
var isEnd = position == value.Length - 1;
if (!char.IsLetter(ch) || isEnd)
{
// Escape sequence has ended
// Or it's a symbol. Assuming in this case it will only be a single char.
if ((isEnd && char.IsLetter(ch)) || position - start == 0)
{
position++;
}
break;
}
position++;
}
var commandSpan = value.Segment(start, position - start);
var command = commandSpan.ToString();
var formulaSource = new SourceSpan(value.Source, initialSrcPosition, commandSpan.End);
SymbolAtom symbolAtom = null;
if (SymbolAtom.TryGetAtom(commandSpan, out symbolAtom))
{
// Symbol was found.
if (symbolAtom.Type == TexAtomType.Accent)
{
var helper = new TexFormulaHelper(formula, formulaSource);
TexFormula accentFormula = ReadScript(formula, value, ref position, environment);
helper.AddAccent(accentFormula, symbolAtom.Name);
}
else if (symbolAtom.Type == TexAtomType.BigOperator)
{
var opAtom = new BigOperatorAtom(formulaSource, symbolAtom, null, null);
formula.Add(AttachScripts(formula, value, ref position, opAtom, true, environment), formulaSource);
}
else
{
formula.Add(
AttachScripts(formula, value, ref position, symbolAtom, true, environment), formulaSource);
}
}
else if (predefinedFormulas.TryGetValue(command, out var factory))
{
// Predefined formula was found.
var predefinedFormula = factory(formulaSource);
var atom = AttachScripts(formula, value, ref position, predefinedFormula.RootAtom, true, environment);
formula.Add(atom, formulaSource);
}
else if (command.Equals("nbsp"))
{
// Space was found.
var atom = AttachScripts(formula, value, ref position, new SpaceAtom(formulaSource), true, environment);
formula.Add(atom, formulaSource);
}
else if (textStyles.Contains(command))
{
// Text style was found.
SkipWhiteSpace(value, ref position);
var styledFormula = command == TexUtilities.TextStyleName
? ConvertRawText(ReadElement(value, ref position), command)
: Parse(ReadElement(value, ref position), command, environment.CreateChildEnvironment());
if (styledFormula.RootAtom == null)
{
throw new TexParseException("Styled text can't be empty!");
}
var atom = AttachScripts(formula, value, ref position, styledFormula.RootAtom, true, environment);
var source = new SourceSpan(formulaSource.Source, formulaSource.Start, position);
formula.Add(atom, source);
}
else if (embeddedCommands.Contains(command) ||
environment.AvailableCommands.ContainsKey(command) ||
_commandRegistry.ContainsKey(command))
{
// Command was found.
var commandAtom = ProcessCommand(
formula,
value,
ref position,
command,
allowClosingDelimiter,
ref closedDelimiter,
environment);
if (commandAtom != null)
{
commandAtom = allowClosingDelimiter
? commandAtom
: AttachScripts(
formula,
value,
ref position,
commandAtom,
true,
environment);
var source = new SourceSpan(formulaSource.Source, formulaSource.Start, commandAtom.Source.End);
formula.Add(commandAtom, source);
}
}
else
{
// Escape sequence is invalid.
throw new TexParseException("Unknown symbol or command or predefined TeXFormula: '" + command + "'");
}
}
private Atom AttachScripts(TexFormula formula, string value, ref int position, Atom atom)
{
if (position == value.Length)
{
return(atom);
}
if (value[position] == superScriptChar || value[position] == subScriptChar)
{
if (position == value.Length - 1)
{
position++;
return(atom);
}
}
else
{
return(atom);
}
TexFormula superscriptFormula = null;
TexFormula subscriptFormula = null;
//0: Undetermined; 1: Not Yet; 2: Yes, we are; 3: Yes, and make it smaller
int markAsBig = 0;
//0: In Beginning;1: We are in _;2: we are in ^
int lastIsSuper = 0;
while (position < value.Length)
{
var ch = value[position];
if (ch == superScriptChar || ch == subScriptChar)
{
if (++position < value.Length && (value[position] == ch))
{
markAsBig = 2;
if (++position < value.Length && (value[position] == ch))
{
markAsBig = 3;
position++;
}
}
bool v = ch == superScriptChar;
if ((v ? superscriptFormula : subscriptFormula) == null)
{
lastIsSuper = v ? 2 : 1;
}
continue;
}
else if (ch == rightGroupChar || (value[position - 1] != '^' && value[position - 1] != '_'))
{
break;
}
if (lastIsSuper == 2)
{
if (superscriptFormula == null)
{
superscriptFormula = ReadScript(formula, value, ref position);
}
else
{
position--;
superscriptFormula.RootAtom = AttachScripts(formula, value, ref position, superscriptFormula.RootAtom);
}
}
else if (lastIsSuper == 1)
{
if (subscriptFormula == null)
{
subscriptFormula = ReadScript(formula, value, ref position);
}
else
{
position--;
subscriptFormula.RootAtom = AttachScripts(formula, value, ref position, subscriptFormula.RootAtom);
}
}
else
{
break;
}
}
if (superscriptFormula == null && subscriptFormula == null)
{
return(atom);
}
// Check whether to return Big Operator or Scripts.
if (atom != null && (atom.GetRightType() == CharType.BigOperator || markAsBig >= 2))
{
return(BigOperatorAtom.Get(atom, subscriptFormula == null ? null : subscriptFormula.GetRoot,
superscriptFormula == null ? null : superscriptFormula.GetRoot, markAsBig == 3));
}
else
{
return(ScriptsAtom.Get(atom, subscriptFormula == null ? null : subscriptFormula.GetRoot,
superscriptFormula == null ? null : superscriptFormula.GetRoot));
}
}
