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use mathml_renderer::{
arena::StringBuilder,
attribute::HtmlTextStyle,
length::{Length, LengthUnit},
symbol,
};
use crate::{
error::{LatexErrKind, LatexError},
parser::{ParseResult, Parser},
specifications::LatexUnit,
token::{EndToken, Mode, TextToken, Token},
};
impl<'arena> Parser<'_, '_, 'arena> {
pub(super) fn extract_text(
&mut self,
initial_style: Option<HtmlTextStyle>,
text_mode: bool,
) -> ParseResult<Vec<(Option<HtmlTextStyle>, &'arena str)>> {
let mut style_stack = vec![(0usize, initial_style)];
let mut str_builder: Option<StringBuilder> = None;
let mut snippets: Vec<(Option<HtmlTextStyle>, &'arena str)> = Vec::new();
let mut accent_to_insert: Option<char> = None;
let mut brace_nesting = 0usize;
while let Some((previous_nesting, current_style)) = style_stack.last().copied() {
let tokloc = if text_mode {
self.tokens.next_any_token()
} else {
self.tokens.next()
};
let (token, span) = tokloc?.into_parts();
let c: Result<char, LatexErrKind> = if let Token::TextMode(text_token) = token {
if text_mode {
match text_token {
TextToken::Accent(accent) => {
if str_builder.is_some() {
accent_to_insert = Some(accent);
continue;
} else {
Err(LatexErrKind::ExpectedArgumentGotEOI)
}
}
TextToken::Letter(ch) => Ok(ch),
}
} else {
Err(LatexErrKind::NotValidInMathMode)
}
} else if matches!(
token,
Token::Letter(_, Mode::MathOrText)
| Token::SquareBracketOpen
| Token::SquareBracketClose
| Token::Digit(_)
| Token::Prime
| Token::Whitespace
| Token::NonBreakingSpace
| Token::OpGreaterThan
| Token::OpLessThan
| Token::OpAmpersand
| Token::InternalStringLiteral(_)
| Token::GroupBegin
| Token::GroupEnd
| Token::MathOrTextMode(_, _)
| Token::Text(_)
| Token::Eoi
| Token::Right
| Token::End(_)
) {
// These tokens are valid in both math and text mode.
match token {
Token::Letter(c, Mode::MathOrText) => Ok(c),
Token::SquareBracketOpen => Ok(symbol::LEFT_SQUARE_BRACKET.as_op().into()),
Token::SquareBracketClose => Ok(symbol::RIGHT_SQUARE_BRACKET.as_op().into()),
Token::Digit(digit) => Ok(digit),
Token::Prime => Ok('’'),
Token::Whitespace | Token::NonBreakingSpace => Ok('\u{A0}'),
tok @ (Token::OpGreaterThan
| Token::OpLessThan
| Token::OpAmpersand
| Token::InternalStringLiteral(_)) => {
let output = match tok {
Token::OpGreaterThan => ">",
Token::OpLessThan => "<",
Token::OpAmpersand => "&",
Token::InternalStringLiteral(content) => content,
_ => unreachable!(),
};
if let Some(str_builder) = &mut str_builder {
str_builder.push_str(output);
continue;
} else {
snippets.push((current_style, output));
style_stack.pop();
brace_nesting = previous_nesting;
if !style_stack.is_empty() {
// If there are still styles to process, we must have been within a group.
str_builder = Some(self.buffer.get_builder());
}
continue;
}
}
Token::GroupBegin => {
if str_builder.is_none() {
str_builder = Some(self.buffer.get_builder());
} else {
brace_nesting += 1;
}
continue;
}
Token::GroupEnd => {
if let Some(builder) = str_builder.take() {
if let Some(new_nesting) = brace_nesting.checked_sub(1) {
brace_nesting = new_nesting;
// TODO: Avoid this back-and-forth with the `str_builder`.
str_builder = Some(builder);
continue;
} else {
if !builder.is_empty() {
let text = builder.finish(self.arena);
snippets.push((current_style, text));
}
style_stack.pop();
brace_nesting = previous_nesting;
if !style_stack.is_empty() {
str_builder = Some(self.buffer.get_builder());
}
continue;
}
} else {
Err(LatexErrKind::ExpectedArgumentGotClose)
}
}
Token::MathOrTextMode(_, ch) => Ok(ch),
Token::Text(style) => {
if let Some(builder) = str_builder.take()
&& !builder.is_empty()
{
let text = builder.finish(self.arena);
snippets.push((current_style, text));
}
style_stack.push((brace_nesting, style));
brace_nesting = 0;
continue;
}
Token::Eoi => {
if str_builder.is_some() {
Err(LatexErrKind::UnclosedGroup(EndToken::GroupClose))
} else {
Err(LatexErrKind::ExpectedArgumentGotEOI)
}
}
Token::Right | Token::End(_) => Err(LatexErrKind::ExpectedArgumentGotClose),
_ => unreachable!(),
}
} else if !text_mode {
// These tokens are only valid in math mode.
match token {
Token::Letter(c, _) | Token::UprightLetter(c) => Ok(c),
Token::Open(op) | Token::Close(op) | Token::Ord(op) => Ok(op.as_op().into()),
Token::BinaryOp(op) => Ok(op.as_op().into()),
Token::Relation(op) => Ok(op.as_op().into()),
Token::ForceRelation(op) => Ok(op.as_char()),
Token::Punctuation(op) => Ok(op.as_op().into()),
Token::PseudoOperator(output) | Token::PseudoOperatorLimits(output) => {
if let Some(str_builder) = &mut str_builder {
str_builder.push_str(output);
continue;
}
snippets.push((current_style, output));
style_stack.pop();
brace_nesting = previous_nesting;
if !style_stack.is_empty() {
// If there are still styles to process, we must have been within a group.
str_builder = Some(self.buffer.get_builder());
}
continue;
}
Token::Space(length) => {
if length == Length::new(1.0, LengthUnit::Em) {
Ok('\u{2003}')
} else if length == LatexUnit::Mu.length_with_unit(5.0) {
Ok('\u{2004}')
} else if length == LatexUnit::Mu.length_with_unit(4.0) {
Ok('\u{205F}')
} else if length == LatexUnit::Mu.length_with_unit(3.0) {
Ok('\u{2009}')
} else {
// Ignore other spaces in text mode.
if str_builder.is_none() {
// This space was the only thing after the style change.
// So we need to pop the style stack and restore the previous nesting.
style_stack.pop();
brace_nesting = previous_nesting;
if !style_stack.is_empty() {
// If there are still styles to process, we must have been within a group.
str_builder = Some(self.buffer.get_builder());
}
}
continue;
}
}
_ => Err(LatexErrKind::CouldNotExtractText),
}
} else {
Err(LatexErrKind::NotValidInTextMode)
};
let c = c.map_err(|err| Box::new(LatexError(span.into(), err)))?;
if let Some(builder) = &mut str_builder {
builder.push_char(c);
if let Some(accent) = accent_to_insert.take() {
builder.push_char(accent);
}
} else {
let mut b = [0u8; 4];
let text = self.arena.alloc_str(c.encode_utf8(&mut b));
snippets.push((current_style, text));
style_stack.pop();
brace_nesting = previous_nesting;
if !style_stack.is_empty() {
// If there are still styles to process, we must have been within a group.
str_builder = Some(self.buffer.get_builder());
}
}
}
Ok(snippets)
}
}