public static Result <TextAtom> TextAtomFromLaTeX(string latexSource)
{
if (string.IsNullOrEmpty(latexSource))
{
return(new TextAtom.List(Array.Empty <TextAtom>()));
}
int endAt = 0;
bool?displayMath = null;
var mathLaTeX = new StringBuilder();
bool backslashEscape = false;
bool afterCommand = false; // ignore spaces after command
bool afterNewline = false;
int dollarCount = 0;
var globalAtoms = new TextAtomListBuilder();
List <BreakAtInfo> breakList = new List <BreakAtInfo>(); // Roslyn bug that assumes breakList is nullable resulting in warnings so var is not used
var breaker = new CustomBreaker(v => breakList.Add(new BreakAtInfo(v.LatestBreakAt, v.LatestWordKind)))
{
BreakNumberAfterText = true,
ThrowIfCharOutOfRange = false
};
breaker.BreakWords(latexSource);
Result CheckDollarCount(int startAt, ref int endAt, TextAtomListBuilder atoms)
{
switch (dollarCount)
{
case 0:
break;
case 1:
dollarCount = 0;
switch (displayMath)
{
case true:
return("Cannot close display math mode with $");
case false:
if (atoms.Math(mathLaTeX.ToString(), false, startAt, ref endAt).Error is string error)
{
return(error);
}
mathLaTeX.Clear();
displayMath = null;
break;
case null:
displayMath = false;
break;
}
break;
case 2:
dollarCount = 0;
switch (displayMath)
{
case true:
if (atoms.Math(mathLaTeX.ToString(), true, startAt - 1, ref endAt).Error is string error)
{
return(error);
}
mathLaTeX.Clear();
displayMath = null;
break;
case false:
return("Cannot close inline math mode with $$");
case null:
displayMath = true;
break;
}
break;
default:
return("Invalid number of $: " + dollarCount);
}
return(Ok());
}
Result <int> BuildBreakList(ReadOnlySpan <char> latex, TextAtomListBuilder atoms,
int i, bool oneCharOnly, char stopChar)
{
void ParagraphBreak()
{
atoms.Break();
atoms.Space(Space.ParagraphIndent);
}
for (; i < breakList.Count; i++)
{
void ObtainSection(ReadOnlySpan <char> latexInput, int index,
out int start, out int end, out ReadOnlySpan <char> section, out WordKind kind)
{
(start, end) = (index == 0 ? 0 : breakList[index - 1].breakAt, breakList[index].breakAt);
section = latexInput.Slice(start, end - start);
kind = breakList[index].wordKind;
}
ObtainSection(latex, i, out var startAt, out endAt, out var textSection, out var wordKind);
bool PreviousSection(ReadOnlySpan <char> latexInput, ref ReadOnlySpan <char> section)
{
bool success = i-- > 0;
if (success)
{
ObtainSection(latexInput, i, out startAt, out endAt, out section, out wordKind);
}
return(success);
}
bool NextSection(ReadOnlySpan <char> latexInput, ref ReadOnlySpan <char> section)
{
bool success = ++i < breakList.Count;
if (success)
{
ObtainSection(latexInput, i, out startAt, out endAt, out section, out wordKind);
}
return(success);
}
Result <TextAtom> ReadArgumentAtom(ReadOnlySpan <char> latexInput)
{
backslashEscape = false;
var argAtoms = new TextAtomListBuilder();
return(BuildBreakList(latexInput, argAtoms, ++i, true, '\0')
.Bind(index => { i = index; return argAtoms.Build(); }));
}
SpanResult <char> ReadArgumentString(ReadOnlySpan <char> latexInput, ref ReadOnlySpan <char> section)
{
afterCommand = false;
if (!NextSection(latexInput, ref section))
{
return(Err("Missing argument"));
}
if (section.IsNot('{'))
{
return(Err("Missing {"));
}
int endingIndex = -1;
//startAt + 1 to not start at the { we started at
bool isEscape = false;
for (int j = startAt + 1, bracketDepth = 0; j < latexInput.Length; j++)
{
if (latexInput[j] == '\\')
{
isEscape = true;
}
else if (latexInput[j] == '{' && !isEscape)
{
bracketDepth++;
}
else if (latexInput[j] == '}' && !isEscape)
{
if (bracketDepth > 0)
{
bracketDepth--;
}
else
{
endingIndex = j; break;
}
}
else
{
isEscape = false;
}
}
if (endingIndex == -1)
{
return(Err("Missing }"));
}
var resultText = latexInput.Slice(endAt, endingIndex - endAt);
while (startAt < endingIndex)
{
_ = NextSection(latexInput, ref section); //this never fails because the above check
}
return(Ok(resultText));
}
Result <Color> ReadColor(ReadOnlySpan <char> latexInput, ref ReadOnlySpan <char> section) =>
ReadArgumentString(latexInput, ref section).Bind(color =>
Color.Create(color, !NoEnhancedColors) is Color value ?
Ok(value) :
Err("Invalid color: " + color.ToString())
);
///<summary>Get punctutation after current section</summary>
ReadOnlySpan <char> NextSectionWhilePunc(ReadOnlySpan <char> latexInput, ref ReadOnlySpan <char> section)
{
int start = endAt;
ReadOnlySpan <char> specialChars = stackalloc[] { '#', '$', '%', '&', '\\', '^', '_', '{', '}', '~' };
while (NextSection(latexInput, ref section))
{
if (wordKind != WordKind.Punc || specialChars.IndexOf(section[0]) != -1)
{
// We have overlooked by one when non-punctuation or special character is encountered
PreviousSection(latexInput, ref section);
break;
}
}
return(latexInput.Slice(start, endAt - start));
}
//Nothing should be before dollar sign checking -- dollar sign checking uses continue;
atoms.TextLength = startAt;
if (textSection.Is('$'))
{
if (backslashEscape)
{
if (displayMath != null)
{
mathLaTeX.Append(@"\$");
}
else
{
atoms.Text("$", NextSectionWhilePunc(latex, ref textSection));
}
}
else
{
dollarCount++;
continue;
}
backslashEscape = false;
}
else
{
{ if (CheckDollarCount(startAt, ref endAt, atoms).Error is string error)
{
return(error);
}
}
switch (backslashEscape, displayMath)
{
public static Result <TextAtom> TextAtomFromLaTeX(string latexSource)
{
if (string.IsNullOrEmpty(latexSource))
{
return(new TextAtom.List(Array.Empty <TextAtom>(), 0));
}
bool? displayMath = null;
StringBuilder mathLaTeX = null;
bool backslashEscape = false;
bool afterCommand = false; //ignore spaces after command
bool afterNewline = false;
int dollarCount = 0;
var globalAtoms = new TextAtomListBuilder();
var breakList = new List <BreakAtInfo>();
breaker.SetNewBreakHandler(v =>
breakList.Add(new BreakAtInfo(v.LatestBreakAt, v.LatestWordKind)));
breaker.BreakWords(latexSource);
Result CheckDollarCount(TextAtomListBuilder atoms)
{
switch (dollarCount)
{
case 0:
break;
case 1:
dollarCount = 0;
switch (displayMath)
{
case true:
return("Cannot close display math mode with $");
case false:
if (atoms.Math(mathLaTeX.ToString(), false).Error is string mathError)
{
return("[Math mode error] " + mathError);
}
mathLaTeX = null;
displayMath = null;
break;
case null:
mathLaTeX = new StringBuilder();
displayMath = false;
break;
}
break;
case 2:
dollarCount = 0;
switch (displayMath)
{
case true:
if (atoms.Math(mathLaTeX.ToString(), true).Error is string mathError)
{
return("[Math mode error] " + mathError);
}
mathLaTeX = null;
displayMath = null;
break;
case false:
return("Cannot close inline math mode with $$");
case null:
mathLaTeX = new StringBuilder();
displayMath = true;
break;
}
break;
default:
return("Invalid number of $: " + dollarCount);
}
return(Ok());
}
Result <int> BuildBreakList(ReadOnlySpan <char> latex, TextAtomListBuilder atoms,
int i, bool oneCharOnly, char stopChar)
{
void ParagraphBreak()
{
atoms.Break(3);
#warning Should the newline and space occupy the same range?
atoms.TextLength -= 3;
atoms.Space(Space.ParagraphIndent, 3);
}
for (; i < breakList.Count; i++)
{
void ObtainSection(ReadOnlySpan <char> latexInput, int index,
out int start, out int end, out ReadOnlySpan <char> section, out WordKind kind)
{
(start, end) = (index == 0 ? 0 : breakList[index - 1].breakAt, breakList[index].breakAt);
section = latexInput.Slice(start, end - start);
kind = breakList[index].wordKind;
}
ObtainSection(latex, i, out var startAt, out var endAt, out var textSection, out var wordKind);
bool PreviousSection(ReadOnlySpan <char> latexInput, ref ReadOnlySpan <char> section)
{
bool success = i-- > 0;
if (success)
{
ObtainSection(latexInput, i, out startAt, out endAt, out section, out wordKind);
}
return(success);
}
bool NextSection(ReadOnlySpan <char> latexInput, ref ReadOnlySpan <char> section)
{
bool success = ++i < breakList.Count;
if (success)
{
ObtainSection(latexInput, i, out startAt, out endAt, out section, out wordKind);
}
return(success);
}
Result <TextAtom.List> ReadArgumentAtom(ReadOnlySpan <char> latexInput)
{
backslashEscape = false;
var argAtoms = new TextAtomListBuilder();
return(BuildBreakList(latexInput, argAtoms, ++i, true, '\0')
.Bind(index => { i = index; return argAtoms.Build(); }));
}
SpanResult <char> ReadArgumentString(ReadOnlySpan <char> latexInput, ref ReadOnlySpan <char> section)
{
afterCommand = false;
if (!NextSection(latexInput, ref section))
{
return(Err("Missing argument"));
}
if (section.IsNot('{'))
{
return(Err("Missing {"));
}
int endingIndex = -1;
//startAt + 1 to not start at the { we started at
bool isEscape = false;
for (int j = startAt + 1, bracketDepth = 0; j < latexInput.Length; j++)
{
if (latexInput[j] == '\\')
{
isEscape = true;
}
else if (latexInput[j] == '{' && !isEscape)
{
bracketDepth++;
}
else if (latexInput[j] == '}' && !isEscape)
{
if (bracketDepth > 0)
{
bracketDepth--;
}
else
{
endingIndex = j; break;
}
}
else
{
isEscape = false;
}
}
if (endingIndex == -1)
{
return(Err("Missing }"));
}
var resultText = latexInput.Slice(endAt, endingIndex - endAt);
while (startAt < endingIndex)
{
_ = NextSection(latexInput, ref section); //this never fails because the above check
}
return(Ok(resultText));
}
ReadOnlySpan <char> NextSectionUntilPunc(ReadOnlySpan <char> latexInput, ref ReadOnlySpan <char> section)
{
int start = endAt;
ReadOnlySpan <char> specialChars = stackalloc[] { '#', '$', '%', '&', '\\', '^', '_', '{', '}', '~' };
while (NextSection(latexInput, ref section))
{
if (wordKind != WordKind.Punc || specialChars.IndexOf(section[0]) != -1)
{
//We have overlooked by one
PreviousSection(latexInput, ref section);
break;
}
}
return(latexInput.Slice(start, endAt - start));
}
//Nothing should be before dollar sign checking -- dollar sign checking uses continue;
atoms.TextLength = startAt;
if (textSection.Is('$'))
{
if (backslashEscape)
{
if (displayMath != null)
{
mathLaTeX.Append(@"\$");
}
else
{
atoms.Text("$", NextSectionUntilPunc(latex, ref textSection));
}
}
else
{
dollarCount++;
continue;
}
backslashEscape = false;
}
else
{
{ if (CheckDollarCount(atoms).Error is string error)
{
return(error);
}
}
if (!backslashEscape)
{
//Unescaped text section, inside display/inline math mode
if (displayMath != null)
{
switch (textSection)
{
case var _ when textSection.Is('$'):
throw new InvalidCodePathException("The $ case should have been accounted for.");
case var _ when textSection.Is('\\'):
backslashEscape = true;
continue;
default:
mathLaTeX.Append(textSection);
break;
}
}
//Unescaped text section, not inside display/inline math mode
else
{
switch (textSection)
{
case var _ when stopChar > 0 && textSection[0] == stopChar:
return(Ok(i));
case var _ when textSection.Is('$'):
throw new InvalidCodePathException("The $ case should have been accounted for.");
case var _ when textSection.Is('\\'):
backslashEscape = true;
continue;
case var _ when textSection.Is('#'):
return("Unexpected command argument reference character # outside of new command definition (currently unsupported)");
case var _ when textSection.Is('^'):
case var _ when textSection.Is('_'):
return($"Unexpected script indicator {textSection[0]} outside of math mode");
case var _ when textSection.Is('&'):
return($"Unexpected alignment tab character & outside of table environments");
case var _ when textSection.Is('~'):
atoms.ControlSpace();
break;
case var _ when textSection.Is('%'):
var comment = new StringBuilder();
while (NextSection(latex, ref textSection) && wordKind != WordKind.NewLine)
{
comment.Append(textSection);
}
atoms.Comment(comment.ToString());
break;
case var _ when textSection.Is('{'):
if (BuildBreakList(latex, atoms, ++i, false, '}').Bind(index => i = index).Error is string error)
{
return(error);
}
break;
case var _ when textSection.Is('}'):
return("Unexpected }, unbalanced braces");
case var _ when wordKind == WordKind.NewLine:
// Consume newlines after commands
// Double newline == paragraph break
if (afterNewline)
{
ParagraphBreak();
afterNewline = false;
break;
}
else
{
atoms.ControlSpace();
afterNewline = true;
continue;
}
case var _ when wordKind == WordKind.Whitespace:
//Collpase spaces
if (afterCommand)
{
continue;
}
else
{
atoms.ControlSpace();
}
break;
default: //Just ordinary text
if (oneCharOnly)
{
if (startAt + 1 < endAt) //Only re-read if current break span is more than 1 long
{
i--;
breakList[i] = new BreakAtInfo(breakList[i].breakAt + 1, breakList[i].wordKind);
}
//Need to allocate in the end :(
//Don't look ahead for punc; we are looking for one char only
atoms.Text(textSection[0].ToString(), default);
}
else
{
atoms.Text(textSection.ToString(), NextSectionUntilPunc(latex, ref textSection));
}
break;
}
}
afterCommand = false;
}
//Escaped text section but in inline/display math mode
else if (displayMath != null)
{
switch (textSection)
{
case var _ when textSection.Is('$'):
throw new InvalidCodePathException("The $ case should have been accounted for.");
case var _ when textSection.Is('('):
return(displayMath switch
{
true => "Cannot open inline math mode in display math mode",
false => "Cannot open inline math mode in inline math mode",
null => throw new InvalidCodePathException("displayMath is null. This switch should not be hit."),
});