summaryrefslogtreecommitdiffstats
path: root/src/parse.rs
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--src/parse.rs996
1 files changed, 996 insertions, 0 deletions
diff --git a/src/parse.rs b/src/parse.rs
new file mode 100644
index 0000000..07239bc
--- /dev/null
+++ b/src/parse.rs
@@ -0,0 +1,996 @@
+use crate::fallback::{
+ self, is_ident_continue, is_ident_start, Group, LexError, Literal, Span, TokenStream,
+ TokenStreamBuilder,
+};
+use crate::{Delimiter, Punct, Spacing, TokenTree};
+use core::char;
+use core::str::{Bytes, CharIndices, Chars};
+
+#[derive(Copy, Clone, Eq, PartialEq)]
+pub(crate) struct Cursor<'a> {
+ pub rest: &'a str,
+ #[cfg(span_locations)]
+ pub off: u32,
+}
+
+impl<'a> Cursor<'a> {
+ pub fn advance(&self, bytes: usize) -> Cursor<'a> {
+ let (_front, rest) = self.rest.split_at(bytes);
+ Cursor {
+ rest,
+ #[cfg(span_locations)]
+ off: self.off + _front.chars().count() as u32,
+ }
+ }
+
+ pub fn starts_with(&self, s: &str) -> bool {
+ self.rest.starts_with(s)
+ }
+
+ pub fn starts_with_char(&self, ch: char) -> bool {
+ self.rest.starts_with(ch)
+ }
+
+ pub fn starts_with_fn<Pattern>(&self, f: Pattern) -> bool
+ where
+ Pattern: FnMut(char) -> bool,
+ {
+ self.rest.starts_with(f)
+ }
+
+ pub fn is_empty(&self) -> bool {
+ self.rest.is_empty()
+ }
+
+ fn len(&self) -> usize {
+ self.rest.len()
+ }
+
+ fn as_bytes(&self) -> &'a [u8] {
+ self.rest.as_bytes()
+ }
+
+ fn bytes(&self) -> Bytes<'a> {
+ self.rest.bytes()
+ }
+
+ fn chars(&self) -> Chars<'a> {
+ self.rest.chars()
+ }
+
+ fn char_indices(&self) -> CharIndices<'a> {
+ self.rest.char_indices()
+ }
+
+ fn parse(&self, tag: &str) -> Result<Cursor<'a>, Reject> {
+ if self.starts_with(tag) {
+ Ok(self.advance(tag.len()))
+ } else {
+ Err(Reject)
+ }
+ }
+}
+
+pub(crate) struct Reject;
+type PResult<'a, O> = Result<(Cursor<'a>, O), Reject>;
+
+fn skip_whitespace(input: Cursor) -> Cursor {
+ let mut s = input;
+
+ while !s.is_empty() {
+ let byte = s.as_bytes()[0];
+ if byte == b'/' {
+ if s.starts_with("//")
+ && (!s.starts_with("///") || s.starts_with("////"))
+ && !s.starts_with("//!")
+ {
+ let (cursor, _) = take_until_newline_or_eof(s);
+ s = cursor;
+ continue;
+ } else if s.starts_with("/**/") {
+ s = s.advance(4);
+ continue;
+ } else if s.starts_with("/*")
+ && (!s.starts_with("/**") || s.starts_with("/***"))
+ && !s.starts_with("/*!")
+ {
+ match block_comment(s) {
+ Ok((rest, _)) => {
+ s = rest;
+ continue;
+ }
+ Err(Reject) => return s,
+ }
+ }
+ }
+ match byte {
+ b' ' | 0x09..=0x0d => {
+ s = s.advance(1);
+ continue;
+ }
+ b if b.is_ascii() => {}
+ _ => {
+ let ch = s.chars().next().unwrap();
+ if is_whitespace(ch) {
+ s = s.advance(ch.len_utf8());
+ continue;
+ }
+ }
+ }
+ return s;
+ }
+ s
+}
+
+fn block_comment(input: Cursor) -> PResult<&str> {
+ if !input.starts_with("/*") {
+ return Err(Reject);
+ }
+
+ let mut depth = 0usize;
+ let bytes = input.as_bytes();
+ let mut i = 0usize;
+ let upper = bytes.len() - 1;
+
+ while i < upper {
+ if bytes[i] == b'/' && bytes[i + 1] == b'*' {
+ depth += 1;
+ i += 1; // eat '*'
+ } else if bytes[i] == b'*' && bytes[i + 1] == b'/' {
+ depth -= 1;
+ if depth == 0 {
+ return Ok((input.advance(i + 2), &input.rest[..i + 2]));
+ }
+ i += 1; // eat '/'
+ }
+ i += 1;
+ }
+
+ Err(Reject)
+}
+
+fn is_whitespace(ch: char) -> bool {
+ // Rust treats left-to-right mark and right-to-left mark as whitespace
+ ch.is_whitespace() || ch == '\u{200e}' || ch == '\u{200f}'
+}
+
+fn word_break(input: Cursor) -> Result<Cursor, Reject> {
+ match input.chars().next() {
+ Some(ch) if is_ident_continue(ch) => Err(Reject),
+ Some(_) | None => Ok(input),
+ }
+}
+
+// Rustc's representation of a macro expansion error in expression position or
+// type position.
+const ERROR: &str = "(/*ERROR*/)";
+
+pub(crate) fn token_stream(mut input: Cursor) -> Result<TokenStream, LexError> {
+ let mut trees = TokenStreamBuilder::new();
+ let mut stack = Vec::new();
+
+ loop {
+ input = skip_whitespace(input);
+
+ if let Ok((rest, ())) = doc_comment(input, &mut trees) {
+ input = rest;
+ continue;
+ }
+
+ #[cfg(span_locations)]
+ let lo = input.off;
+
+ let first = match input.bytes().next() {
+ Some(first) => first,
+ None => match stack.last() {
+ None => return Ok(trees.build()),
+ #[cfg(span_locations)]
+ Some((lo, _frame)) => {
+ return Err(LexError {
+ span: Span { lo: *lo, hi: *lo },
+ })
+ }
+ #[cfg(not(span_locations))]
+ Some(_frame) => return Err(LexError { span: Span {} }),
+ },
+ };
+
+ if let Some(open_delimiter) = match first {
+ b'(' if !input.starts_with(ERROR) => Some(Delimiter::Parenthesis),
+ b'[' => Some(Delimiter::Bracket),
+ b'{' => Some(Delimiter::Brace),
+ _ => None,
+ } {
+ input = input.advance(1);
+ let frame = (open_delimiter, trees);
+ #[cfg(span_locations)]
+ let frame = (lo, frame);
+ stack.push(frame);
+ trees = TokenStreamBuilder::new();
+ } else if let Some(close_delimiter) = match first {
+ b')' => Some(Delimiter::Parenthesis),
+ b']' => Some(Delimiter::Bracket),
+ b'}' => Some(Delimiter::Brace),
+ _ => None,
+ } {
+ let frame = match stack.pop() {
+ Some(frame) => frame,
+ None => return Err(lex_error(input)),
+ };
+ #[cfg(span_locations)]
+ let (lo, frame) = frame;
+ let (open_delimiter, outer) = frame;
+ if open_delimiter != close_delimiter {
+ return Err(lex_error(input));
+ }
+ input = input.advance(1);
+ let mut g = Group::new(open_delimiter, trees.build());
+ g.set_span(Span {
+ #[cfg(span_locations)]
+ lo,
+ #[cfg(span_locations)]
+ hi: input.off,
+ });
+ trees = outer;
+ trees.push_token_from_parser(TokenTree::Group(crate::Group::_new_fallback(g)));
+ } else {
+ let (rest, mut tt) = match leaf_token(input) {
+ Ok((rest, tt)) => (rest, tt),
+ Err(Reject) => return Err(lex_error(input)),
+ };
+ tt.set_span(crate::Span::_new_fallback(Span {
+ #[cfg(span_locations)]
+ lo,
+ #[cfg(span_locations)]
+ hi: rest.off,
+ }));
+ trees.push_token_from_parser(tt);
+ input = rest;
+ }
+ }
+}
+
+fn lex_error(cursor: Cursor) -> LexError {
+ #[cfg(not(span_locations))]
+ let _ = cursor;
+ LexError {
+ span: Span {
+ #[cfg(span_locations)]
+ lo: cursor.off,
+ #[cfg(span_locations)]
+ hi: cursor.off,
+ },
+ }
+}
+
+fn leaf_token(input: Cursor) -> PResult<TokenTree> {
+ if let Ok((input, l)) = literal(input) {
+ // must be parsed before ident
+ Ok((input, TokenTree::Literal(crate::Literal::_new_fallback(l))))
+ } else if let Ok((input, p)) = punct(input) {
+ Ok((input, TokenTree::Punct(p)))
+ } else if let Ok((input, i)) = ident(input) {
+ Ok((input, TokenTree::Ident(i)))
+ } else if input.starts_with(ERROR) {
+ let rest = input.advance(ERROR.len());
+ let repr = crate::Literal::_new_fallback(Literal::_new(ERROR.to_owned()));
+ Ok((rest, TokenTree::Literal(repr)))
+ } else {
+ Err(Reject)
+ }
+}
+
+fn ident(input: Cursor) -> PResult<crate::Ident> {
+ if [
+ "r\"", "r#\"", "r##", "b\"", "b\'", "br\"", "br#", "c\"", "cr\"", "cr#",
+ ]
+ .iter()
+ .any(|prefix| input.starts_with(prefix))
+ {
+ Err(Reject)
+ } else {
+ ident_any(input)
+ }
+}
+
+fn ident_any(input: Cursor) -> PResult<crate::Ident> {
+ let raw = input.starts_with("r#");
+ let rest = input.advance((raw as usize) << 1);
+
+ let (rest, sym) = ident_not_raw(rest)?;
+
+ if !raw {
+ let ident = crate::Ident::_new(crate::imp::Ident::new_unchecked(
+ sym,
+ fallback::Span::call_site(),
+ ));
+ return Ok((rest, ident));
+ }
+
+ match sym {
+ "_" | "super" | "self" | "Self" | "crate" => return Err(Reject),
+ _ => {}
+ }
+
+ let ident = crate::Ident::_new(crate::imp::Ident::new_raw_unchecked(
+ sym,
+ fallback::Span::call_site(),
+ ));
+ Ok((rest, ident))
+}
+
+fn ident_not_raw(input: Cursor) -> PResult<&str> {
+ let mut chars = input.char_indices();
+
+ match chars.next() {
+ Some((_, ch)) if is_ident_start(ch) => {}
+ _ => return Err(Reject),
+ }
+
+ let mut end = input.len();
+ for (i, ch) in chars {
+ if !is_ident_continue(ch) {
+ end = i;
+ break;
+ }
+ }
+
+ Ok((input.advance(end), &input.rest[..end]))
+}
+
+pub(crate) fn literal(input: Cursor) -> PResult<Literal> {
+ let rest = literal_nocapture(input)?;
+ let end = input.len() - rest.len();
+ Ok((rest, Literal::_new(input.rest[..end].to_string())))
+}
+
+fn literal_nocapture(input: Cursor) -> Result<Cursor, Reject> {
+ if let Ok(ok) = string(input) {
+ Ok(ok)
+ } else if let Ok(ok) = byte_string(input) {
+ Ok(ok)
+ } else if let Ok(ok) = c_string(input) {
+ Ok(ok)
+ } else if let Ok(ok) = byte(input) {
+ Ok(ok)
+ } else if let Ok(ok) = character(input) {
+ Ok(ok)
+ } else if let Ok(ok) = float(input) {
+ Ok(ok)
+ } else if let Ok(ok) = int(input) {
+ Ok(ok)
+ } else {
+ Err(Reject)
+ }
+}
+
+fn literal_suffix(input: Cursor) -> Cursor {
+ match ident_not_raw(input) {
+ Ok((input, _)) => input,
+ Err(Reject) => input,
+ }
+}
+
+fn string(input: Cursor) -> Result<Cursor, Reject> {
+ if let Ok(input) = input.parse("\"") {
+ cooked_string(input)
+ } else if let Ok(input) = input.parse("r") {
+ raw_string(input)
+ } else {
+ Err(Reject)
+ }
+}
+
+fn cooked_string(mut input: Cursor) -> Result<Cursor, Reject> {
+ let mut chars = input.char_indices();
+
+ while let Some((i, ch)) = chars.next() {
+ match ch {
+ '"' => {
+ let input = input.advance(i + 1);
+ return Ok(literal_suffix(input));
+ }
+ '\r' => match chars.next() {
+ Some((_, '\n')) => {}
+ _ => break,
+ },
+ '\\' => match chars.next() {
+ Some((_, 'x')) => {
+ backslash_x_char(&mut chars)?;
+ }
+ Some((_, 'n' | 'r' | 't' | '\\' | '\'' | '"' | '0')) => {}
+ Some((_, 'u')) => {
+ backslash_u(&mut chars)?;
+ }
+ Some((newline, ch @ ('\n' | '\r'))) => {
+ input = input.advance(newline + 1);
+ trailing_backslash(&mut input, ch as u8)?;
+ chars = input.char_indices();
+ }
+ _ => break,
+ },
+ _ch => {}
+ }
+ }
+ Err(Reject)
+}
+
+fn raw_string(input: Cursor) -> Result<Cursor, Reject> {
+ let (input, delimiter) = delimiter_of_raw_string(input)?;
+ let mut bytes = input.bytes().enumerate();
+ while let Some((i, byte)) = bytes.next() {
+ match byte {
+ b'"' if input.rest[i + 1..].starts_with(delimiter) => {
+ let rest = input.advance(i + 1 + delimiter.len());
+ return Ok(literal_suffix(rest));
+ }
+ b'\r' => match bytes.next() {
+ Some((_, b'\n')) => {}
+ _ => break,
+ },
+ _ => {}
+ }
+ }
+ Err(Reject)
+}
+
+fn byte_string(input: Cursor) -> Result<Cursor, Reject> {
+ if let Ok(input) = input.parse("b\"") {
+ cooked_byte_string(input)
+ } else if let Ok(input) = input.parse("br") {
+ raw_byte_string(input)
+ } else {
+ Err(Reject)
+ }
+}
+
+fn cooked_byte_string(mut input: Cursor) -> Result<Cursor, Reject> {
+ let mut bytes = input.bytes().enumerate();
+ while let Some((offset, b)) = bytes.next() {
+ match b {
+ b'"' => {
+ let input = input.advance(offset + 1);
+ return Ok(literal_suffix(input));
+ }
+ b'\r' => match bytes.next() {
+ Some((_, b'\n')) => {}
+ _ => break,
+ },
+ b'\\' => match bytes.next() {
+ Some((_, b'x')) => {
+ backslash_x_byte(&mut bytes)?;
+ }
+ Some((_, b'n' | b'r' | b't' | b'\\' | b'0' | b'\'' | b'"')) => {}
+ Some((newline, b @ (b'\n' | b'\r'))) => {
+ input = input.advance(newline + 1);
+ trailing_backslash(&mut input, b)?;
+ bytes = input.bytes().enumerate();
+ }
+ _ => break,
+ },
+ b if b.is_ascii() => {}
+ _ => break,
+ }
+ }
+ Err(Reject)
+}
+
+fn delimiter_of_raw_string(input: Cursor) -> PResult<&str> {
+ for (i, byte) in input.bytes().enumerate() {
+ match byte {
+ b'"' => {
+ if i > 255 {
+ // https://github.com/rust-lang/rust/pull/95251
+ return Err(Reject);
+ }
+ return Ok((input.advance(i + 1), &input.rest[..i]));
+ }
+ b'#' => {}
+ _ => break,
+ }
+ }
+ Err(Reject)
+}
+
+fn raw_byte_string(input: Cursor) -> Result<Cursor, Reject> {
+ let (input, delimiter) = delimiter_of_raw_string(input)?;
+ let mut bytes = input.bytes().enumerate();
+ while let Some((i, byte)) = bytes.next() {
+ match byte {
+ b'"' if input.rest[i + 1..].starts_with(delimiter) => {
+ let rest = input.advance(i + 1 + delimiter.len());
+ return Ok(literal_suffix(rest));
+ }
+ b'\r' => match bytes.next() {
+ Some((_, b'\n')) => {}
+ _ => break,
+ },
+ other => {
+ if !other.is_ascii() {
+ break;
+ }
+ }
+ }
+ }
+ Err(Reject)
+}
+
+fn c_string(input: Cursor) -> Result<Cursor, Reject> {
+ if let Ok(input) = input.parse("c\"") {
+ cooked_c_string(input)
+ } else if let Ok(input) = input.parse("cr") {
+ raw_c_string(input)
+ } else {
+ Err(Reject)
+ }
+}
+
+fn raw_c_string(input: Cursor) -> Result<Cursor, Reject> {
+ let (input, delimiter) = delimiter_of_raw_string(input)?;
+ let mut bytes = input.bytes().enumerate();
+ while let Some((i, byte)) = bytes.next() {
+ match byte {
+ b'"' if input.rest[i + 1..].starts_with(delimiter) => {
+ let rest = input.advance(i + 1 + delimiter.len());
+ return Ok(literal_suffix(rest));
+ }
+ b'\r' => match bytes.next() {
+ Some((_, b'\n')) => {}
+ _ => break,
+ },
+ b'\0' => break,
+ _ => {}
+ }
+ }
+ Err(Reject)
+}
+
+fn cooked_c_string(mut input: Cursor) -> Result<Cursor, Reject> {
+ let mut chars = input.char_indices();
+
+ while let Some((i, ch)) = chars.next() {
+ match ch {
+ '"' => {
+ let input = input.advance(i + 1);
+ return Ok(literal_suffix(input));
+ }
+ '\r' => match chars.next() {
+ Some((_, '\n')) => {}
+ _ => break,
+ },
+ '\\' => match chars.next() {
+ Some((_, 'x')) => {
+ backslash_x_nonzero(&mut chars)?;
+ }
+ Some((_, 'n' | 'r' | 't' | '\\' | '\'' | '"')) => {}
+ Some((_, 'u')) => {
+ if backslash_u(&mut chars)? == '\0' {
+ break;
+ }
+ }
+ Some((newline, ch @ ('\n' | '\r'))) => {
+ input = input.advance(newline + 1);
+ trailing_backslash(&mut input, ch as u8)?;
+ chars = input.char_indices();
+ }
+ _ => break,
+ },
+ '\0' => break,
+ _ch => {}
+ }
+ }
+ Err(Reject)
+}
+
+fn byte(input: Cursor) -> Result<Cursor, Reject> {
+ let input = input.parse("b'")?;
+ let mut bytes = input.bytes().enumerate();
+ let ok = match bytes.next().map(|(_, b)| b) {
+ Some(b'\\') => match bytes.next().map(|(_, b)| b) {
+ Some(b'x') => backslash_x_byte(&mut bytes).is_ok(),
+ Some(b'n' | b'r' | b't' | b'\\' | b'0' | b'\'' | b'"') => true,
+ _ => false,
+ },
+ b => b.is_some(),
+ };
+ if !ok {
+ return Err(Reject);
+ }
+ let (offset, _) = bytes.next().ok_or(Reject)?;
+ if !input.chars().as_str().is_char_boundary(offset) {
+ return Err(Reject);
+ }
+ let input = input.advance(offset).parse("'")?;
+ Ok(literal_suffix(input))
+}
+
+fn character(input: Cursor) -> Result<Cursor, Reject> {
+ let input = input.parse("'")?;
+ let mut chars = input.char_indices();
+ let ok = match chars.next().map(|(_, ch)| ch) {
+ Some('\\') => match chars.next().map(|(_, ch)| ch) {
+ Some('x') => backslash_x_char(&mut chars).is_ok(),
+ Some('u') => backslash_u(&mut chars).is_ok(),
+ Some('n' | 'r' | 't' | '\\' | '0' | '\'' | '"') => true,
+ _ => false,
+ },
+ ch => ch.is_some(),
+ };
+ if !ok {
+ return Err(Reject);
+ }
+ let (idx, _) = chars.next().ok_or(Reject)?;
+ let input = input.advance(idx).parse("'")?;
+ Ok(literal_suffix(input))
+}
+
+macro_rules! next_ch {
+ ($chars:ident @ $pat:pat) => {
+ match $chars.next() {
+ Some((_, ch)) => match ch {
+ $pat => ch,
+ _ => return Err(Reject),
+ },
+ None => return Err(Reject),
+ }
+ };
+}
+
+fn backslash_x_char<I>(chars: &mut I) -> Result<(), Reject>
+where
+ I: Iterator<Item = (usize, char)>,
+{
+ next_ch!(chars @ '0'..='7');
+ next_ch!(chars @ '0'..='9' | 'a'..='f' | 'A'..='F');
+ Ok(())
+}
+
+fn backslash_x_byte<I>(chars: &mut I) -> Result<(), Reject>
+where
+ I: Iterator<Item = (usize, u8)>,
+{
+ next_ch!(chars @ b'0'..=b'9' | b'a'..=b'f' | b'A'..=b'F');
+ next_ch!(chars @ b'0'..=b'9' | b'a'..=b'f' | b'A'..=b'F');
+ Ok(())
+}
+
+fn backslash_x_nonzero<I>(chars: &mut I) -> Result<(), Reject>
+where
+ I: Iterator<Item = (usize, char)>,
+{
+ let first = next_ch!(chars @ '0'..='9' | 'a'..='f' | 'A'..='F');
+ let second = next_ch!(chars @ '0'..='9' | 'a'..='f' | 'A'..='F');
+ if first == '0' && second == '0' {
+ Err(Reject)
+ } else {
+ Ok(())
+ }
+}
+
+fn backslash_u<I>(chars: &mut I) -> Result<char, Reject>
+where
+ I: Iterator<Item = (usize, char)>,
+{
+ next_ch!(chars @ '{');
+ let mut value = 0;
+ let mut len = 0;
+ for (_, ch) in chars {
+ let digit = match ch {
+ '0'..='9' => ch as u8 - b'0',
+ 'a'..='f' => 10 + ch as u8 - b'a',
+ 'A'..='F' => 10 + ch as u8 - b'A',
+ '_' if len > 0 => continue,
+ '}' if len > 0 => return char::from_u32(value).ok_or(Reject),
+ _ => break,
+ };
+ if len == 6 {
+ break;
+ }
+ value *= 0x10;
+ value += u32::from(digit);
+ len += 1;
+ }
+ Err(Reject)
+}
+
+fn trailing_backslash(input: &mut Cursor, mut last: u8) -> Result<(), Reject> {
+ let mut whitespace = input.bytes().enumerate();
+ loop {
+ if last == b'\r' && whitespace.next().map_or(true, |(_, b)| b != b'\n') {
+ return Err(Reject);
+ }
+ match whitespace.next() {
+ Some((_, b @ (b' ' | b'\t' | b'\n' | b'\r'))) => {
+ last = b;
+ }
+ Some((offset, _)) => {
+ *input = input.advance(offset);
+ return Ok(());
+ }
+ None => return Err(Reject),
+ }
+ }
+}
+
+fn float(input: Cursor) -> Result<Cursor, Reject> {
+ let mut rest = float_digits(input)?;
+ if let Some(ch) = rest.chars().next() {
+ if is_ident_start(ch) {
+ rest = ident_not_raw(rest)?.0;
+ }
+ }
+ word_break(rest)
+}
+
+fn float_digits(input: Cursor) -> Result<Cursor, Reject> {
+ let mut chars = input.chars().peekable();
+ match chars.next() {
+ Some(ch) if '0' <= ch && ch <= '9' => {}
+ _ => return Err(Reject),
+ }
+
+ let mut len = 1;
+ let mut has_dot = false;
+ let mut has_exp = false;
+ while let Some(&ch) = chars.peek() {
+ match ch {
+ '0'..='9' | '_' => {
+ chars.next();
+ len += 1;
+ }
+ '.' => {
+ if has_dot {
+ break;
+ }
+ chars.next();
+ if chars
+ .peek()
+ .map_or(false, |&ch| ch == '.' || is_ident_start(ch))
+ {
+ return Err(Reject);
+ }
+ len += 1;
+ has_dot = true;
+ }
+ 'e' | 'E' => {
+ chars.next();
+ len += 1;
+ has_exp = true;
+ break;
+ }
+ _ => break,
+ }
+ }
+
+ if !(has_dot || has_exp) {
+ return Err(Reject);
+ }
+
+ if has_exp {
+ let token_before_exp = if has_dot {
+ Ok(input.advance(len - 1))
+ } else {
+ Err(Reject)
+ };
+ let mut has_sign = false;
+ let mut has_exp_value = false;
+ while let Some(&ch) = chars.peek() {
+ match ch {
+ '+' | '-' => {
+ if has_exp_value {
+ break;
+ }
+ if has_sign {
+ return token_before_exp;
+ }
+ chars.next();
+ len += 1;
+ has_sign = true;
+ }
+ '0'..='9' => {
+ chars.next();
+ len += 1;
+ has_exp_value = true;
+ }
+ '_' => {
+ chars.next();
+ len += 1;
+ }
+ _ => break,
+ }
+ }
+ if !has_exp_value {
+ return token_before_exp;
+ }
+ }
+
+ Ok(input.advance(len))
+}
+
+fn int(input: Cursor) -> Result<Cursor, Reject> {
+ let mut rest = digits(input)?;
+ if let Some(ch) = rest.chars().next() {
+ if is_ident_start(ch) {
+ rest = ident_not_raw(rest)?.0;
+ }
+ }
+ word_break(rest)
+}
+
+fn digits(mut input: Cursor) -> Result<Cursor, Reject> {
+ let base = if input.starts_with("0x") {
+ input = input.advance(2);
+ 16
+ } else if input.starts_with("0o") {
+ input = input.advance(2);
+ 8
+ } else if input.starts_with("0b") {
+ input = input.advance(2);
+ 2
+ } else {
+ 10
+ };
+
+ let mut len = 0;
+ let mut empty = true;
+ for b in input.bytes() {
+ match b {
+ b'0'..=b'9' => {
+ let digit = (b - b'0') as u64;
+ if digit >= base {
+ return Err(Reject);
+ }
+ }
+ b'a'..=b'f' => {
+ let digit = 10 + (b - b'a') as u64;
+ if digit >= base {
+ break;
+ }
+ }
+ b'A'..=b'F' => {
+ let digit = 10 + (b - b'A') as u64;
+ if digit >= base {
+ break;
+ }
+ }
+ b'_' => {
+ if empty && base == 10 {
+ return Err(Reject);
+ }
+ len += 1;
+ continue;
+ }
+ _ => break,
+ };
+ len += 1;
+ empty = false;
+ }
+ if empty {
+ Err(Reject)
+ } else {
+ Ok(input.advance(len))
+ }
+}
+
+fn punct(input: Cursor) -> PResult<Punct> {
+ let (rest, ch) = punct_char(input)?;
+ if ch == '\'' {
+ if ident_any(rest)?.0.starts_with_char('\'') {
+ Err(Reject)
+ } else {
+ Ok((rest, Punct::new('\'', Spacing::Joint)))
+ }
+ } else {
+ let kind = match punct_char(rest) {
+ Ok(_) => Spacing::Joint,
+ Err(Reject) => Spacing::Alone,
+ };
+ Ok((rest, Punct::new(ch, kind)))
+ }
+}
+
+fn punct_char(input: Cursor) -> PResult<char> {
+ if input.starts_with("//") || input.starts_with("/*") {
+ // Do not accept `/` of a comment as a punct.
+ return Err(Reject);
+ }
+
+ let mut chars = input.chars();
+ let first = match chars.next() {
+ Some(ch) => ch,
+ None => {
+ return Err(Reject);
+ }
+ };
+ let recognized = "~!@#$%^&*-=+|;:,<.>/?'";
+ if recognized.contains(first) {
+ Ok((input.advance(first.len_utf8()), first))
+ } else {
+ Err(Reject)
+ }
+}
+
+fn doc_comment<'a>(input: Cursor<'a>, trees: &mut TokenStreamBuilder) -> PResult<'a, ()> {
+ #[cfg(span_locations)]
+ let lo = input.off;
+ let (rest, (comment, inner)) = doc_comment_contents(input)?;
+ let fallback_span = Span {
+ #[cfg(span_locations)]
+ lo,
+ #[cfg(span_locations)]
+ hi: rest.off,
+ };
+ let span = crate::Span::_new_fallback(fallback_span);
+
+ let mut scan_for_bare_cr = comment;
+ while let Some(cr) = scan_for_bare_cr.find('\r') {
+ let rest = &scan_for_bare_cr[cr + 1..];
+ if !rest.starts_with('\n') {
+ return Err(Reject);
+ }
+ scan_for_bare_cr = rest;
+ }
+
+ let mut pound = Punct::new('#', Spacing::Alone);
+ pound.set_span(span);
+ trees.push_token_from_parser(TokenTree::Punct(pound));
+
+ if inner {
+ let mut bang = Punct::new('!', Spacing::Alone);
+ bang.set_span(span);
+ trees.push_token_from_parser(TokenTree::Punct(bang));
+ }
+
+ let doc_ident = crate::Ident::_new(crate::imp::Ident::new_unchecked("doc", fallback_span));
+ let mut equal = Punct::new('=', Spacing::Alone);
+ equal.set_span(span);
+ let mut literal = crate::Literal::string(comment);
+ literal.set_span(span);
+ let mut bracketed = TokenStreamBuilder::with_capacity(3);
+ bracketed.push_token_from_parser(TokenTree::Ident(doc_ident));
+ bracketed.push_token_from_parser(TokenTree::Punct(equal));
+ bracketed.push_token_from_parser(TokenTree::Literal(literal));
+ let group = Group::new(Delimiter::Bracket, bracketed.build());
+ let mut group = crate::Group::_new_fallback(group);
+ group.set_span(span);
+ trees.push_token_from_parser(TokenTree::Group(group));
+
+ Ok((rest, ()))
+}
+
+fn doc_comment_contents(input: Cursor) -> PResult<(&str, bool)> {
+ if input.starts_with("//!") {
+ let input = input.advance(3);
+ let (input, s) = take_until_newline_or_eof(input);
+ Ok((input, (s, true)))
+ } else if input.starts_with("/*!") {
+ let (input, s) = block_comment(input)?;
+ Ok((input, (&s[3..s.len() - 2], true)))
+ } else if input.starts_with("///") {
+ let input = input.advance(3);
+ if input.starts_with_char('/') {
+ return Err(Reject);
+ }
+ let (input, s) = take_until_newline_or_eof(input);
+ Ok((input, (s, false)))
+ } else if input.starts_with("/**") && !input.rest[3..].starts_with('*') {
+ let (input, s) = block_comment(input)?;
+ Ok((input, (&s[3..s.len() - 2], false)))
+ } else {
+ Err(Reject)
+ }
+}
+
+fn take_until_newline_or_eof(input: Cursor) -> (Cursor, &str) {
+ let chars = input.char_indices();
+
+ for (i, ch) in chars {
+ if ch == '\n' {
+ return (input.advance(i), &input.rest[..i]);
+ } else if ch == '\r' && input.rest[i + 1..].starts_with('\n') {
+ return (input.advance(i + 1), &input.rest[..i]);
+ }
+ }
+
+ (input.advance(input.len()), input.rest)
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-18 22:22:51 +0000