| //! Macro support for format strings |
| //! |
| //! These structures are used when parsing format strings for the compiler. |
| //! Parsing does not happen at runtime: structures of `std::fmt::rt` are |
| //! generated instead. |
| |
| #![doc( |
| html_root_url = "https://doc.rust-lang.org/nightly/", |
| html_playground_url = "https://play.rust-lang.org/", |
| test(attr(deny(warnings))) |
| )] |
| #![feature(nll)] |
| #![feature(or_patterns)] |
| #![feature(rustc_private)] |
| #![feature(unicode_internals)] |
| #![feature(bool_to_option)] |
| |
| pub use Alignment::*; |
| pub use Count::*; |
| pub use Flag::*; |
| pub use Piece::*; |
| pub use Position::*; |
| |
| use std::iter; |
| use std::str; |
| use std::string; |
| |
| use rustc_span::{InnerSpan, Symbol}; |
| |
| /// The type of format string that we are parsing. |
| #[derive(Copy, Clone, Debug, Eq, PartialEq)] |
| pub enum ParseMode { |
| /// A normal format string as per `format_args!`. |
| Format, |
| /// An inline assembly template string for `asm!`. |
| InlineAsm, |
| } |
| |
| #[derive(Copy, Clone)] |
| struct InnerOffset(usize); |
| |
| impl InnerOffset { |
| fn to(self, end: InnerOffset) -> InnerSpan { |
| InnerSpan::new(self.0, end.0) |
| } |
| } |
| |
| /// A piece is a portion of the format string which represents the next part |
| /// to emit. These are emitted as a stream by the `Parser` class. |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| pub enum Piece<'a> { |
| /// A literal string which should directly be emitted |
| String(&'a str), |
| /// This describes that formatting should process the next argument (as |
| /// specified inside) for emission. |
| NextArgument(Argument<'a>), |
| } |
| |
| /// Representation of an argument specification. |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| pub struct Argument<'a> { |
| /// Where to find this argument |
| pub position: Position, |
| /// How to format the argument |
| pub format: FormatSpec<'a>, |
| } |
| |
| /// Specification for the formatting of an argument in the format string. |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| pub struct FormatSpec<'a> { |
| /// Optionally specified character to fill alignment with. |
| pub fill: Option<char>, |
| /// Optionally specified alignment. |
| pub align: Alignment, |
| /// Packed version of various flags provided. |
| pub flags: u32, |
| /// The integer precision to use. |
| pub precision: Count, |
| /// The span of the precision formatting flag (for diagnostics). |
| pub precision_span: Option<InnerSpan>, |
| /// The string width requested for the resulting format. |
| pub width: Count, |
| /// The span of the width formatting flag (for diagnostics). |
| pub width_span: Option<InnerSpan>, |
| /// The descriptor string representing the name of the format desired for |
| /// this argument, this can be empty or any number of characters, although |
| /// it is required to be one word. |
| pub ty: &'a str, |
| /// The span of the descriptor string (for diagnostics). |
| pub ty_span: Option<InnerSpan>, |
| } |
| |
| /// Enum describing where an argument for a format can be located. |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| pub enum Position { |
| /// The argument is implied to be located at an index |
| ArgumentImplicitlyIs(usize), |
| /// The argument is located at a specific index given in the format |
| ArgumentIs(usize), |
| /// The argument has a name. |
| ArgumentNamed(Symbol), |
| } |
| |
| impl Position { |
| pub fn index(&self) -> Option<usize> { |
| match self { |
| ArgumentIs(i) | ArgumentImplicitlyIs(i) => Some(*i), |
| _ => None, |
| } |
| } |
| } |
| |
| /// Enum of alignments which are supported. |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| pub enum Alignment { |
| /// The value will be aligned to the left. |
| AlignLeft, |
| /// The value will be aligned to the right. |
| AlignRight, |
| /// The value will be aligned in the center. |
| AlignCenter, |
| /// The value will take on a default alignment. |
| AlignUnknown, |
| } |
| |
| /// Various flags which can be applied to format strings. The meaning of these |
| /// flags is defined by the formatters themselves. |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| pub enum Flag { |
| /// A `+` will be used to denote positive numbers. |
| FlagSignPlus, |
| /// A `-` will be used to denote negative numbers. This is the default. |
| FlagSignMinus, |
| /// An alternate form will be used for the value. In the case of numbers, |
| /// this means that the number will be prefixed with the supplied string. |
| FlagAlternate, |
| /// For numbers, this means that the number will be padded with zeroes, |
| /// and the sign (`+` or `-`) will precede them. |
| FlagSignAwareZeroPad, |
| /// For Debug / `?`, format integers in lower-case hexadecimal. |
| FlagDebugLowerHex, |
| /// For Debug / `?`, format integers in upper-case hexadecimal. |
| FlagDebugUpperHex, |
| } |
| |
| /// A count is used for the precision and width parameters of an integer, and |
| /// can reference either an argument or a literal integer. |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| pub enum Count { |
| /// The count is specified explicitly. |
| CountIs(usize), |
| /// The count is specified by the argument with the given name. |
| CountIsName(Symbol), |
| /// The count is specified by the argument at the given index. |
| CountIsParam(usize), |
| /// The count is implied and cannot be explicitly specified. |
| CountImplied, |
| } |
| |
| pub struct ParseError { |
| pub description: string::String, |
| pub note: Option<string::String>, |
| pub label: string::String, |
| pub span: InnerSpan, |
| pub secondary_label: Option<(string::String, InnerSpan)>, |
| } |
| |
| /// The parser structure for interpreting the input format string. This is |
| /// modeled as an iterator over `Piece` structures to form a stream of tokens |
| /// being output. |
| /// |
| /// This is a recursive-descent parser for the sake of simplicity, and if |
| /// necessary there's probably lots of room for improvement performance-wise. |
| pub struct Parser<'a> { |
| mode: ParseMode, |
| input: &'a str, |
| cur: iter::Peekable<str::CharIndices<'a>>, |
| /// Error messages accumulated during parsing |
| pub errors: Vec<ParseError>, |
| /// Current position of implicit positional argument pointer |
| pub curarg: usize, |
| /// `Some(raw count)` when the string is "raw", used to position spans correctly |
| style: Option<usize>, |
| /// Start and end byte offset of every successfully parsed argument |
| pub arg_places: Vec<InnerSpan>, |
| /// Characters that need to be shifted |
| skips: Vec<usize>, |
| /// Span of the last opening brace seen, used for error reporting |
| last_opening_brace: Option<InnerSpan>, |
| /// Whether the source string is comes from `println!` as opposed to `format!` or `print!` |
| append_newline: bool, |
| /// Whether this formatting string is a literal or it comes from a macro. |
| pub is_literal: bool, |
| /// Start position of the current line. |
| cur_line_start: usize, |
| /// Start and end byte offset of every line of the format string. Excludes |
| /// newline characters and leading whitespace. |
| pub line_spans: Vec<InnerSpan>, |
| } |
| |
| impl<'a> Iterator for Parser<'a> { |
| type Item = Piece<'a>; |
| |
| fn next(&mut self) -> Option<Piece<'a>> { |
| if let Some(&(pos, c)) = self.cur.peek() { |
| match c { |
| '{' => { |
| let curr_last_brace = self.last_opening_brace; |
| let byte_pos = self.to_span_index(pos); |
| self.last_opening_brace = Some(byte_pos.to(InnerOffset(byte_pos.0 + 1))); |
| self.cur.next(); |
| if self.consume('{') { |
| self.last_opening_brace = curr_last_brace; |
| |
| Some(String(self.string(pos + 1))) |
| } else { |
| let arg = self.argument(); |
| if let Some(end) = self.must_consume('}') { |
| let start = self.to_span_index(pos); |
| let end = self.to_span_index(end + 1); |
| if self.is_literal { |
| self.arg_places.push(start.to(end)); |
| } |
| } |
| Some(NextArgument(arg)) |
| } |
| } |
| '}' => { |
| self.cur.next(); |
| if self.consume('}') { |
| Some(String(self.string(pos + 1))) |
| } else { |
| let err_pos = self.to_span_index(pos); |
| self.err_with_note( |
| "unmatched `}` found", |
| "unmatched `}`", |
| "if you intended to print `}`, you can escape it using `}}`", |
| err_pos.to(err_pos), |
| ); |
| None |
| } |
| } |
| _ => Some(String(self.string(pos))), |
| } |
| } else { |
| if self.is_literal { |
| let start = self.to_span_index(self.cur_line_start); |
| let end = self.to_span_index(self.input.len()); |
| let span = start.to(end); |
| if self.line_spans.last() != Some(&span) { |
| self.line_spans.push(span); |
| } |
| } |
| None |
| } |
| } |
| } |
| |
| impl<'a> Parser<'a> { |
| /// Creates a new parser for the given format string |
| pub fn new( |
| s: &'a str, |
| style: Option<usize>, |
| snippet: Option<string::String>, |
| append_newline: bool, |
| mode: ParseMode, |
| ) -> Parser<'a> { |
| let (skips, is_literal) = find_skips_from_snippet(snippet, style); |
| Parser { |
| mode, |
| input: s, |
| cur: s.char_indices().peekable(), |
| errors: vec![], |
| curarg: 0, |
| style, |
| arg_places: vec![], |
| skips, |
| last_opening_brace: None, |
| append_newline, |
| is_literal, |
| cur_line_start: 0, |
| line_spans: vec![], |
| } |
| } |
| |
| /// Notifies of an error. The message doesn't actually need to be of type |
| /// String, but I think it does when this eventually uses conditions so it |
| /// might as well start using it now. |
| fn err<S1: Into<string::String>, S2: Into<string::String>>( |
| &mut self, |
| description: S1, |
| label: S2, |
| span: InnerSpan, |
| ) { |
| self.errors.push(ParseError { |
| description: description.into(), |
| note: None, |
| label: label.into(), |
| span, |
| secondary_label: None, |
| }); |
| } |
| |
| /// Notifies of an error. The message doesn't actually need to be of type |
| /// String, but I think it does when this eventually uses conditions so it |
| /// might as well start using it now. |
| fn err_with_note< |
| S1: Into<string::String>, |
| S2: Into<string::String>, |
| S3: Into<string::String>, |
| >( |
| &mut self, |
| description: S1, |
| label: S2, |
| note: S3, |
| span: InnerSpan, |
| ) { |
| self.errors.push(ParseError { |
| description: description.into(), |
| note: Some(note.into()), |
| label: label.into(), |
| span, |
| secondary_label: None, |
| }); |
| } |
| |
| /// Optionally consumes the specified character. If the character is not at |
| /// the current position, then the current iterator isn't moved and `false` is |
| /// returned, otherwise the character is consumed and `true` is returned. |
| fn consume(&mut self, c: char) -> bool { |
| self.consume_pos(c).is_some() |
| } |
| |
| /// Optionally consumes the specified character. If the character is not at |
| /// the current position, then the current iterator isn't moved and `None` is |
| /// returned, otherwise the character is consumed and the current position is |
| /// returned. |
| fn consume_pos(&mut self, c: char) -> Option<usize> { |
| if let Some(&(pos, maybe)) = self.cur.peek() { |
| if c == maybe { |
| self.cur.next(); |
| return Some(pos); |
| } |
| } |
| None |
| } |
| |
| fn to_span_index(&self, pos: usize) -> InnerOffset { |
| let mut pos = pos; |
| // This handles the raw string case, the raw argument is the number of # |
| // in r###"..."### (we need to add one because of the `r`). |
| let raw = self.style.map(|raw| raw + 1).unwrap_or(0); |
| for skip in &self.skips { |
| if pos > *skip { |
| pos += 1; |
| } else if pos == *skip && raw == 0 { |
| pos += 1; |
| } else { |
| break; |
| } |
| } |
| InnerOffset(raw + pos + 1) |
| } |
| |
| /// Forces consumption of the specified character. If the character is not |
| /// found, an error is emitted. |
| fn must_consume(&mut self, c: char) -> Option<usize> { |
| self.ws(); |
| |
| if let Some(&(pos, maybe)) = self.cur.peek() { |
| if c == maybe { |
| self.cur.next(); |
| Some(pos) |
| } else { |
| let pos = self.to_span_index(pos); |
| let description = format!("expected `'}}'`, found `{:?}`", maybe); |
| let label = "expected `}`".to_owned(); |
| let (note, secondary_label) = if c == '}' { |
| ( |
| Some( |
| "if you intended to print `{`, you can escape it using `{{`".to_owned(), |
| ), |
| self.last_opening_brace |
| .map(|sp| ("because of this opening brace".to_owned(), sp)), |
| ) |
| } else { |
| (None, None) |
| }; |
| self.errors.push(ParseError { |
| description, |
| note, |
| label, |
| span: pos.to(pos), |
| secondary_label, |
| }); |
| None |
| } |
| } else { |
| let description = format!("expected `{:?}` but string was terminated", c); |
| // point at closing `"` |
| let pos = self.input.len() - if self.append_newline { 1 } else { 0 }; |
| let pos = self.to_span_index(pos); |
| if c == '}' { |
| let label = format!("expected `{:?}`", c); |
| let (note, secondary_label) = if c == '}' { |
| ( |
| Some( |
| "if you intended to print `{`, you can escape it using `{{`".to_owned(), |
| ), |
| self.last_opening_brace |
| .map(|sp| ("because of this opening brace".to_owned(), sp)), |
| ) |
| } else { |
| (None, None) |
| }; |
| self.errors.push(ParseError { |
| description, |
| note, |
| label, |
| span: pos.to(pos), |
| secondary_label, |
| }); |
| } else { |
| self.err(description, format!("expected `{:?}`", c), pos.to(pos)); |
| } |
| None |
| } |
| } |
| |
| /// Consumes all whitespace characters until the first non-whitespace character |
| fn ws(&mut self) { |
| while let Some(&(_, c)) = self.cur.peek() { |
| if c.is_whitespace() { |
| self.cur.next(); |
| } else { |
| break; |
| } |
| } |
| } |
| |
| /// Parses all of a string which is to be considered a "raw literal" in a |
| /// format string. This is everything outside of the braces. |
| fn string(&mut self, start: usize) -> &'a str { |
| // we may not consume the character, peek the iterator |
| while let Some(&(pos, c)) = self.cur.peek() { |
| match c { |
| '{' | '}' => { |
| return &self.input[start..pos]; |
| } |
| '\n' if self.is_literal => { |
| let start = self.to_span_index(self.cur_line_start); |
| let end = self.to_span_index(pos); |
| self.line_spans.push(start.to(end)); |
| self.cur_line_start = pos + 1; |
| self.cur.next(); |
| } |
| _ => { |
| if self.is_literal && pos == self.cur_line_start && c.is_whitespace() { |
| self.cur_line_start = pos + c.len_utf8(); |
| } |
| self.cur.next(); |
| } |
| } |
| } |
| &self.input[start..self.input.len()] |
| } |
| |
| /// Parses an `Argument` structure, or what's contained within braces inside the format string. |
| fn argument(&mut self) -> Argument<'a> { |
| let pos = self.position(); |
| let format = match self.mode { |
| ParseMode::Format => self.format(), |
| ParseMode::InlineAsm => self.inline_asm(), |
| }; |
| |
| // Resolve position after parsing format spec. |
| let pos = match pos { |
| Some(position) => position, |
| None => { |
| let i = self.curarg; |
| self.curarg += 1; |
| ArgumentImplicitlyIs(i) |
| } |
| }; |
| |
| Argument { position: pos, format } |
| } |
| |
| /// Parses a positional argument for a format. This could either be an |
| /// integer index of an argument, a named argument, or a blank string. |
| /// Returns `Some(parsed_position)` if the position is not implicitly |
| /// consuming a macro argument, `None` if it's the case. |
| fn position(&mut self) -> Option<Position> { |
| if let Some(i) = self.integer() { |
| Some(ArgumentIs(i)) |
| } else { |
| match self.cur.peek() { |
| Some(&(_, c)) if rustc_lexer::is_id_start(c) => { |
| Some(ArgumentNamed(Symbol::intern(self.word()))) |
| } |
| |
| // This is an `ArgumentNext`. |
| // Record the fact and do the resolution after parsing the |
| // format spec, to make things like `{:.*}` work. |
| _ => None, |
| } |
| } |
| } |
| |
| /// Parses a format specifier at the current position, returning all of the |
| /// relevant information in the `FormatSpec` struct. |
| fn format(&mut self) -> FormatSpec<'a> { |
| let mut spec = FormatSpec { |
| fill: None, |
| align: AlignUnknown, |
| flags: 0, |
| precision: CountImplied, |
| precision_span: None, |
| width: CountImplied, |
| width_span: None, |
| ty: &self.input[..0], |
| ty_span: None, |
| }; |
| if !self.consume(':') { |
| return spec; |
| } |
| |
| // fill character |
| if let Some(&(_, c)) = self.cur.peek() { |
| match self.cur.clone().nth(1) { |
| Some((_, '>' | '<' | '^')) => { |
| spec.fill = Some(c); |
| self.cur.next(); |
| } |
| _ => {} |
| } |
| } |
| // Alignment |
| if self.consume('<') { |
| spec.align = AlignLeft; |
| } else if self.consume('>') { |
| spec.align = AlignRight; |
| } else if self.consume('^') { |
| spec.align = AlignCenter; |
| } |
| // Sign flags |
| if self.consume('+') { |
| spec.flags |= 1 << (FlagSignPlus as u32); |
| } else if self.consume('-') { |
| spec.flags |= 1 << (FlagSignMinus as u32); |
| } |
| // Alternate marker |
| if self.consume('#') { |
| spec.flags |= 1 << (FlagAlternate as u32); |
| } |
| // Width and precision |
| let mut havewidth = false; |
| |
| if self.consume('0') { |
| // small ambiguity with '0$' as a format string. In theory this is a |
| // '0' flag and then an ill-formatted format string with just a '$' |
| // and no count, but this is better if we instead interpret this as |
| // no '0' flag and '0$' as the width instead. |
| if self.consume('$') { |
| spec.width = CountIsParam(0); |
| havewidth = true; |
| } else { |
| spec.flags |= 1 << (FlagSignAwareZeroPad as u32); |
| } |
| } |
| if !havewidth { |
| let width_span_start = if let Some((pos, _)) = self.cur.peek() { *pos } else { 0 }; |
| let (w, sp) = self.count(width_span_start); |
| spec.width = w; |
| spec.width_span = sp; |
| } |
| if let Some(start) = self.consume_pos('.') { |
| if let Some(end) = self.consume_pos('*') { |
| // Resolve `CountIsNextParam`. |
| // We can do this immediately as `position` is resolved later. |
| let i = self.curarg; |
| self.curarg += 1; |
| spec.precision = CountIsParam(i); |
| spec.precision_span = |
| Some(self.to_span_index(start).to(self.to_span_index(end + 1))); |
| } else { |
| let (p, sp) = self.count(start); |
| spec.precision = p; |
| spec.precision_span = sp; |
| } |
| } |
| let ty_span_start = self.cur.peek().map(|(pos, _)| *pos); |
| // Optional radix followed by the actual format specifier |
| if self.consume('x') { |
| if self.consume('?') { |
| spec.flags |= 1 << (FlagDebugLowerHex as u32); |
| spec.ty = "?"; |
| } else { |
| spec.ty = "x"; |
| } |
| } else if self.consume('X') { |
| if self.consume('?') { |
| spec.flags |= 1 << (FlagDebugUpperHex as u32); |
| spec.ty = "?"; |
| } else { |
| spec.ty = "X"; |
| } |
| } else if self.consume('?') { |
| spec.ty = "?"; |
| } else { |
| spec.ty = self.word(); |
| let ty_span_end = self.cur.peek().map(|(pos, _)| *pos); |
| if !spec.ty.is_empty() { |
| spec.ty_span = ty_span_start |
| .and_then(|s| ty_span_end.map(|e| (s, e))) |
| .map(|(start, end)| self.to_span_index(start).to(self.to_span_index(end))); |
| } |
| } |
| spec |
| } |
| |
| /// Parses an inline assembly template modifier at the current position, returning the modifier |
| /// in the `ty` field of the `FormatSpec` struct. |
| fn inline_asm(&mut self) -> FormatSpec<'a> { |
| let mut spec = FormatSpec { |
| fill: None, |
| align: AlignUnknown, |
| flags: 0, |
| precision: CountImplied, |
| precision_span: None, |
| width: CountImplied, |
| width_span: None, |
| ty: &self.input[..0], |
| ty_span: None, |
| }; |
| if !self.consume(':') { |
| return spec; |
| } |
| |
| let ty_span_start = self.cur.peek().map(|(pos, _)| *pos); |
| spec.ty = self.word(); |
| let ty_span_end = self.cur.peek().map(|(pos, _)| *pos); |
| if !spec.ty.is_empty() { |
| spec.ty_span = ty_span_start |
| .and_then(|s| ty_span_end.map(|e| (s, e))) |
| .map(|(start, end)| self.to_span_index(start).to(self.to_span_index(end))); |
| } |
| |
| spec |
| } |
| |
| /// Parses a `Count` parameter at the current position. This does not check |
| /// for 'CountIsNextParam' because that is only used in precision, not |
| /// width. |
| fn count(&mut self, start: usize) -> (Count, Option<InnerSpan>) { |
| if let Some(i) = self.integer() { |
| if let Some(end) = self.consume_pos('$') { |
| let span = self.to_span_index(start).to(self.to_span_index(end + 1)); |
| (CountIsParam(i), Some(span)) |
| } else { |
| (CountIs(i), None) |
| } |
| } else { |
| let tmp = self.cur.clone(); |
| let word = self.word(); |
| if word.is_empty() { |
| self.cur = tmp; |
| (CountImplied, None) |
| } else if self.consume('$') { |
| (CountIsName(Symbol::intern(word)), None) |
| } else { |
| self.cur = tmp; |
| (CountImplied, None) |
| } |
| } |
| } |
| |
| /// Parses a word starting at the current position. A word is the same as |
| /// Rust identifier, except that it can't start with `_` character. |
| fn word(&mut self) -> &'a str { |
| let start = match self.cur.peek() { |
| Some(&(pos, c)) if rustc_lexer::is_id_start(c) => { |
| self.cur.next(); |
| pos |
| } |
| _ => { |
| return ""; |
| } |
| }; |
| let mut end = None; |
| while let Some(&(pos, c)) = self.cur.peek() { |
| if rustc_lexer::is_id_continue(c) { |
| self.cur.next(); |
| } else { |
| end = Some(pos); |
| break; |
| } |
| } |
| let end = end.unwrap_or(self.input.len()); |
| let word = &self.input[start..end]; |
| if word == "_" { |
| self.err_with_note( |
| "invalid argument name `_`", |
| "invalid argument name", |
| "argument name cannot be a single underscore", |
| self.to_span_index(start).to(self.to_span_index(end)), |
| ); |
| } |
| word |
| } |
| |
| /// Optionally parses an integer at the current position. This doesn't deal |
| /// with overflow at all, it's just accumulating digits. |
| fn integer(&mut self) -> Option<usize> { |
| let mut cur = 0; |
| let mut found = false; |
| while let Some(&(_, c)) = self.cur.peek() { |
| if let Some(i) = c.to_digit(10) { |
| cur = cur * 10 + i as usize; |
| found = true; |
| self.cur.next(); |
| } else { |
| break; |
| } |
| } |
| found.then_some(cur) |
| } |
| } |
| |
| /// Finds the indices of all characters that have been processed and differ between the actual |
| /// written code (code snippet) and the `InternedString` that gets processed in the `Parser` |
| /// in order to properly synthethise the intra-string `Span`s for error diagnostics. |
| fn find_skips_from_snippet( |
| snippet: Option<string::String>, |
| str_style: Option<usize>, |
| ) -> (Vec<usize>, bool) { |
| let snippet = match snippet { |
| Some(ref s) if s.starts_with('"') || s.starts_with("r#") => s, |
| _ => return (vec![], false), |
| }; |
| |
| fn find_skips(snippet: &str, is_raw: bool) -> Vec<usize> { |
| let mut eat_ws = false; |
| let mut s = snippet.chars().enumerate().peekable(); |
| let mut skips = vec![]; |
| while let Some((pos, c)) = s.next() { |
| match (c, s.peek()) { |
| // skip whitespace and empty lines ending in '\\' |
| ('\\', Some((next_pos, '\n'))) if !is_raw => { |
| eat_ws = true; |
| skips.push(pos); |
| skips.push(*next_pos); |
| let _ = s.next(); |
| } |
| ('\\', Some((next_pos, '\n' | 'n' | 't'))) if eat_ws => { |
| skips.push(pos); |
| skips.push(*next_pos); |
| let _ = s.next(); |
| } |
| (' ' | '\n' | '\t', _) if eat_ws => { |
| skips.push(pos); |
| } |
| ('\\', Some((next_pos, 'n' | 't' | '0' | '\\' | '\'' | '\"'))) => { |
| skips.push(*next_pos); |
| let _ = s.next(); |
| } |
| ('\\', Some((_, 'x'))) if !is_raw => { |
| for _ in 0..3 { |
| // consume `\xAB` literal |
| if let Some((pos, _)) = s.next() { |
| skips.push(pos); |
| } else { |
| break; |
| } |
| } |
| } |
| ('\\', Some((_, 'u'))) if !is_raw => { |
| if let Some((pos, _)) = s.next() { |
| skips.push(pos); |
| } |
| if let Some((next_pos, next_c)) = s.next() { |
| if next_c == '{' { |
| skips.push(next_pos); |
| let mut i = 0; // consume up to 6 hexanumeric chars + closing `}` |
| while let (Some((next_pos, c)), true) = (s.next(), i < 7) { |
| if c.is_digit(16) { |
| skips.push(next_pos); |
| } else if c == '}' { |
| skips.push(next_pos); |
| break; |
| } else { |
| break; |
| } |
| i += 1; |
| } |
| } else if next_c.is_digit(16) { |
| skips.push(next_pos); |
| // We suggest adding `{` and `}` when appropriate, accept it here as if |
| // it were correct |
| let mut i = 0; // consume up to 6 hexanumeric chars |
| while let (Some((next_pos, c)), _) = (s.next(), i < 6) { |
| if c.is_digit(16) { |
| skips.push(next_pos); |
| } else { |
| break; |
| } |
| i += 1; |
| } |
| } |
| } |
| } |
| _ if eat_ws => { |
| // `take_while(|c| c.is_whitespace())` |
| eat_ws = false; |
| } |
| _ => {} |
| } |
| } |
| skips |
| } |
| |
| let r_start = str_style.map(|r| r + 1).unwrap_or(0); |
| let r_end = str_style.map(|r| r).unwrap_or(0); |
| let s = &snippet[r_start + 1..snippet.len() - r_end - 1]; |
| (find_skips(s, str_style.is_some()), true) |
| } |
| |
| #[cfg(test)] |
| mod tests; |
