private TexFormula Parse(
SourceSpan value,
ref int position,
bool allowClosingDelimiter,
string textStyle,
ICommandEnvironment environment)
{
var formula = new TexFormula {
Source = value, TextStyle = textStyle
};
var closedDelimiter = false;
var skipWhiteSpace = ShouldSkipWhiteSpace(textStyle);
var initialPosition = position;
while (position < value.Length && !(allowClosingDelimiter && closedDelimiter))
{
char ch = value[position];
var source = value.Segment(position, 1);
if (IsWhiteSpace(ch))
{
if (!skipWhiteSpace)
{
formula.Add(new SpaceAtom(source), source);
}
position++;
}
else if (ch == escapeChar)
{
ProcessEscapeSequence(
formula,
value,
ref position,
allowClosingDelimiter,
ref closedDelimiter,
environment);
}
else if (ch == leftGroupChar)
{
var groupValue = ReadElement(value, ref position);
var parsedGroup = Parse(groupValue, textStyle, environment.CreateChildEnvironment());
var innerGroupAtom = parsedGroup.RootAtom ?? new RowAtom(groupValue);
var groupAtom = new TypedAtom(
innerGroupAtom.Source,
innerGroupAtom,
TexAtomType.Ordinary,
TexAtomType.Ordinary);
var scriptsAtom = this.AttachScripts(formula, value, ref position, groupAtom, true, environment);
formula.Add(scriptsAtom, value.Segment(initialPosition, position - initialPosition));
}
else if (ch == rightGroupChar)
{
throw new TexParseException("Found a closing '" + rightGroupChar
+ "' without an opening '" + leftGroupChar + "'!");
}
else if (ch == superScriptChar || ch == subScriptChar || ch == primeChar)
{
if (position == 0)
{
throw new TexParseException("Every script needs a base: \""
+ superScriptChar + "\", \"" + subScriptChar + "\" and \""
+ primeChar + "\" can't be the first character!");
}
else
{
throw new TexParseException("Double scripts found! Try using more braces.");
}
}
else
{
var character = ConvertCharacter(formula, ref position, source, environment);
if (character != null)
{
var scriptsAtom = AttachScripts(
formula,
value,
ref position,
character,
skipWhiteSpace,
environment);
formula.Add(scriptsAtom, value.Segment(initialPosition, position));
}
}
}
return(formula);
}
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 TexFormula ReadScript(
TexFormula formula,
SourceSpan value,
ref int position,
ICommandEnvironment environment) =>
Parse(ReadElement(value, ref position), formula.TextStyle, environment.CreateChildEnvironment());
/// <remarks>May return <c>null</c> for commands that produce no atoms.</remarks>
private Atom ProcessCommand(
TexFormula formula,
SourceSpan value,
ref int position,
string command,
bool allowClosingDelimiter,
ref bool closedDelimiter,
ICommandEnvironment environment)
{
int start = position - command.Length;
SourceSpan source;
switch (command)
{
case "frac":
{
var numeratorFormula = Parse(
ReadElement(value, ref position),
formula.TextStyle,
environment.CreateChildEnvironment());
var denominatorFormula = Parse(
ReadElement(value, ref position),
formula.TextStyle,
environment.CreateChildEnvironment());
source = value.Segment(start, position - start);
return(new FractionAtom(source, numeratorFormula.RootAtom, denominatorFormula.RootAtom, true));
}
case "left":
{
SkipWhiteSpace(value, ref position);
if (position == value.Length)
{
throw new TexParseException("`left` command should be passed a delimiter");
}
var delimiter = value[position];
++position;
var left = position;
var internals = ParseUntilDelimiter(value, ref position, formula.TextStyle, environment);
var opening = GetDelimiterSymbol(
GetDelimeterMapping(delimiter),
value.Segment(start, left - start));
if (opening == null)
{
throw new TexParseException($"Cannot find delimiter named {delimiter}");
}
var closing = internals.ClosingDelimiter;
source = value.Segment(start, position - start);
return(new FencedAtom(source, internals.Body, opening, closing));
}
case "overline":
{
var overlineFormula = Parse(
ReadElement(value, ref position),
formula.TextStyle,
environment.CreateChildEnvironment());
source = value.Segment(start, position - start);
return(new OverlinedAtom(source, overlineFormula.RootAtom));
}
case "right":
{
if (!allowClosingDelimiter)
{
throw new TexParseException("`right` command is not allowed without `left`");
}
SkipWhiteSpace(value, ref position);
if (position == value.Length)
{
throw new TexParseException("`right` command should be passed a delimiter");
}
var delimiter = value[position];
++position;
var closing = GetDelimiterSymbol(
GetDelimeterMapping(delimiter),
value.Segment(start, position - start));
if (closing == null)
{
throw new TexParseException($"Cannot find delimiter named {delimiter}");
}
closedDelimiter = true;
return(closing);
}
case "sqrt":
{
// Command is radical.
SkipWhiteSpace(value, ref position);
TexFormula degreeFormula = null;
if (value.Length > position && value[position] == leftBracketChar)
{
// Degree of radical is specified.
degreeFormula = Parse(
ReadElementGroup(value, ref position, leftBracketChar, rightBracketChar),
formula.TextStyle,
environment.CreateChildEnvironment());
}
var sqrtFormula = this.Parse(
ReadElement(value, ref position),
formula.TextStyle,
environment.CreateChildEnvironment());
source = value.Segment(start, position - start);
return(new Radical(source, sqrtFormula.RootAtom, degreeFormula?.RootAtom));
}
case "color":
{
var colorName = ReadElement(value, ref position);
if (!predefinedColors.TryGetValue(colorName.ToString(), out var color))
{
throw new TexParseException($"Color {colorName} not found");
}
var bodyValue = ReadElement(value, ref position);
var bodyFormula = Parse(bodyValue, formula.TextStyle, environment.CreateChildEnvironment());
source = value.Segment(start, position - start);
return(new StyledAtom(source, bodyFormula.RootAtom, null, new SolidColorBrush(color)));
}
case "colorbox":
{
var colorName = ReadElement(value, ref position);
var remainingString = ReadElement(value, ref position);
var remaining = Parse(remainingString, formula.TextStyle, environment.CreateChildEnvironment());
if (predefinedColors.TryGetValue(colorName.ToString(), out var color))
{
source = value.Segment(start, position - start);
return(new StyledAtom(source, remaining.RootAtom, new SolidColorBrush(color), null));
}
throw new TexParseException($"Color {colorName} not found");
}
}
if (environment.AvailableCommands.TryGetValue(command, out var parser) ||
_commandRegistry.TryGetValue(command, out parser))
{
var context = new CommandContext(this, formula, environment, value, start, position);
var parseResult = parser.ProcessCommand(context);
if (parseResult.NextPosition < position)
{
throw new TexParseException(
$"Incorrect parser behavior for command {command}: NextPosition = {parseResult.NextPosition}, position = {position}. Parser did not made any progress.");
}
position = parseResult.NextPosition;
return(parseResult.Atom);
}
throw new TexParseException("Invalid command.");
}
public MatrixInternalEnvironment(
ICommandEnvironment parentEnvironment,
List <List <Atom> > rows) : base(parentEnvironment.CreateChildEnvironment(), GetCommands(rows))
{
_rows = rows;
}