//! Main module defining the lexer and parser. use crate::engine::{ Precedence, KEYWORD_DEBUG, KEYWORD_EVAL, KEYWORD_FN_PTR, KEYWORD_FN_PTR_CALL, KEYWORD_FN_PTR_CURRY, KEYWORD_IS_DEF_VAR, KEYWORD_PRINT, KEYWORD_THIS, KEYWORD_TYPE_OF, }; use crate::func::native::OnParseTokenCallback; use crate::{Engine, Identifier, LexError, SmartString, StaticVec, INT, UNSIGNED_INT}; #[cfg(feature = "no_std")] use std::prelude::v1::*; use std::{ borrow::Cow, cell::RefCell, char, fmt, iter::{FusedIterator, Peekable}, num::NonZeroUsize, ops::{Add, AddAssign}, rc::Rc, str::{Chars, FromStr}, }; /// _(internals)_ A type containing commands to control the tokenizer. #[derive(Debug, Clone, Eq, PartialEq, Default, Hash)] pub struct TokenizerControlBlock { /// Is the current tokenizer position within an interpolated text string? /// This flag allows switching the tokenizer back to _text_ parsing after an interpolation stream. pub is_within_text: bool, /// Collection of global comments. #[cfg(feature = "metadata")] pub global_comments: Vec, } impl TokenizerControlBlock { /// Create a new `TokenizerControlBlock`. #[inline(always)] #[must_use] pub const fn new() -> Self { Self { is_within_text: false, #[cfg(feature = "metadata")] global_comments: Vec::new(), } } } /// _(internals)_ A shared object that allows control of the tokenizer from outside. pub type TokenizerControl = Rc>; type LERR = LexError; /// Separator character for numbers. const NUMBER_SEPARATOR: char = '_'; /// A stream of tokens. pub type TokenStream<'a> = Peekable>; /// A location (line number + character position) in the input script. /// /// # Limitations /// /// In order to keep footprint small, both line number and character position have 16-bit resolution, /// meaning they go up to a maximum of 65,535 lines and 65,535 characters per line. /// /// Advancing beyond the maximum line length or maximum number of lines is not an error but has no effect. #[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Clone, Copy)] pub struct Position { /// Line number: 0 = none #[cfg(not(feature = "no_position"))] line: u16, /// Character position: 0 = BOL #[cfg(not(feature = "no_position"))] pos: u16, } impl Position { /// A [`Position`] representing no position. pub const NONE: Self = Self { #[cfg(not(feature = "no_position"))] line: 0, #[cfg(not(feature = "no_position"))] pos: 0, }; /// A [`Position`] representing the first position. pub const START: Self = Self { #[cfg(not(feature = "no_position"))] line: 1, #[cfg(not(feature = "no_position"))] pos: 0, }; /// Create a new [`Position`]. /// /// `line` must not be zero. /// /// If `position` is zero, then it is at the beginning of a line. /// /// # Panics /// /// Panics if `line` is zero. #[inline(always)] #[must_use] pub const fn new(line: u16, position: u16) -> Self { assert!(line != 0, "line cannot be zero"); let _pos = position; Self { #[cfg(not(feature = "no_position"))] line, #[cfg(not(feature = "no_position"))] pos: _pos, } } /// Get the line number (1-based), or [`None`] if there is no position. #[inline] #[must_use] pub const fn line(self) -> Option { #[cfg(not(feature = "no_position"))] return if self.is_none() { None } else { Some(self.line as usize) }; #[cfg(feature = "no_position")] return None; } /// Get the character position (1-based), or [`None`] if at beginning of a line. #[inline] #[must_use] pub const fn position(self) -> Option { #[cfg(not(feature = "no_position"))] return if self.is_none() || self.pos == 0 { None } else { Some(self.pos as usize) }; #[cfg(feature = "no_position")] return None; } /// Advance by one character position. #[inline] pub(crate) fn advance(&mut self) { #[cfg(not(feature = "no_position"))] { assert!(!self.is_none(), "cannot advance Position::none"); // Advance up to maximum position if self.pos < u16::MAX { self.pos += 1; } } } /// Go backwards by one character position. /// /// # Panics /// /// Panics if already at beginning of a line - cannot rewind to a previous line. #[inline] pub(crate) fn rewind(&mut self) { #[cfg(not(feature = "no_position"))] { assert!(!self.is_none(), "cannot rewind Position::none"); assert!(self.pos > 0, "cannot rewind at position 0"); self.pos -= 1; } } /// Advance to the next line. #[inline] pub(crate) fn new_line(&mut self) { #[cfg(not(feature = "no_position"))] { assert!(!self.is_none(), "cannot advance Position::none"); // Advance up to maximum position if self.line < u16::MAX { self.line += 1; self.pos = 0; } } } /// Is this [`Position`] at the beginning of a line? #[inline] #[must_use] pub const fn is_beginning_of_line(self) -> bool { #[cfg(not(feature = "no_position"))] return self.pos == 0 && !self.is_none(); #[cfg(feature = "no_position")] return false; } /// Is there no [`Position`]? #[inline] #[must_use] pub const fn is_none(self) -> bool { #[cfg(not(feature = "no_position"))] return self.line == 0 && self.pos == 0; #[cfg(feature = "no_position")] return true; } /// Returns an fallback [`Position`] if it is [`NONE`][Position::NONE]? #[inline] #[must_use] pub const fn or_else(self, pos: Self) -> Self { if self.is_none() { pos } else { self } } /// Print this [`Position`] for debug purposes. #[inline] pub(crate) fn debug_print(self, _f: &mut fmt::Formatter<'_>) -> fmt::Result { if !self.is_none() { write!(_f, " @ {:?}", self)?; } Ok(()) } } impl Default for Position { #[inline(always)] fn default() -> Self { Self::START } } impl fmt::Display for Position { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { if self.is_none() { write!(f, "none")?; } else { #[cfg(not(feature = "no_position"))] write!(f, "line {}, position {}", self.line, self.pos)?; #[cfg(feature = "no_position")] unreachable!("no position"); } Ok(()) } } impl fmt::Debug for Position { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { if self.is_none() { f.write_str("none") } else { #[cfg(not(feature = "no_position"))] if self.is_beginning_of_line() { write!(f, "{}", self.line) } else { write!(f, "{}:{}", self.line, self.pos) } #[cfg(feature = "no_position")] unreachable!("no position"); } } } impl Add for Position { type Output = Self; fn add(self, rhs: Self) -> Self::Output { if rhs.is_none() { self } else { #[cfg(not(feature = "no_position"))] return Self { line: self.line + rhs.line - 1, pos: if rhs.is_beginning_of_line() { self.pos } else { self.pos + rhs.pos - 1 }, }; #[cfg(feature = "no_position")] unreachable!("no position"); } } } impl AddAssign for Position { fn add_assign(&mut self, rhs: Self) { *self = *self + rhs; } } /// _(internals)_ A span consisting of a starting and an ending [positions][Position]. /// Exported under the `internals` feature only. #[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Clone, Copy)] pub struct Span { /// Starting [position][Position]. start: Position, /// Ending [position][Position]. end: Position, } impl Default for Span { fn default() -> Self { Self::NONE } } impl Span { /// Empty [`Span`]. pub const NONE: Self = Self::new(Position::NONE, Position::NONE); /// Create a new [`Span`]. #[inline(always)] #[must_use] pub const fn new(start: Position, end: Position) -> Self { Self { start, end } } /// Is this [`Span`] non-existent? #[inline(always)] #[must_use] pub const fn is_none(&self) -> bool { self.start.is_none() && self.end.is_none() } /// Get the [`Span`]'s starting [position][Position]. #[inline(always)] #[must_use] pub const fn start(&self) -> Position { self.start } /// Get the [`Span`]'s ending [position][Position]. #[inline(always)] #[must_use] pub const fn end(&self) -> Position { self.end } } impl fmt::Display for Span { #[inline] fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { let _f = f; #[cfg(not(feature = "no_position"))] match (self.start(), self.end()) { (Position::NONE, Position::NONE) => write!(_f, "{:?}", Position::NONE), (Position::NONE, end) => write!(_f, "..{:?}", end), (start, Position::NONE) => write!(_f, "{:?}", start), (start, end) if start.line() != end.line() => { write!(_f, "{:?}-{:?}", start, end) } (start, end) => write!( _f, "{}:{}-{}", start.line().unwrap(), start.position().unwrap_or(0), end.position().unwrap_or(0) ), } #[cfg(feature = "no_position")] Ok(()) } } impl fmt::Debug for Span { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::Display::fmt(self, f) } } /// _(internals)_ A Rhai language token. /// Exported under the `internals` feature only. #[derive(Debug, PartialEq, Clone, Hash)] #[non_exhaustive] pub enum Token { /// An `INT` constant. IntegerConstant(INT), /// A `FLOAT` constant. /// /// Reserved under the `no_float` feature. #[cfg(not(feature = "no_float"))] FloatConstant(crate::ast::FloatWrapper), /// A [`Decimal`][rust_decimal::Decimal] constant. /// /// Requires the `decimal` feature. #[cfg(feature = "decimal")] DecimalConstant(rust_decimal::Decimal), /// An identifier. Identifier(Identifier), /// A character constant. CharConstant(char), /// A string constant. StringConstant(SmartString), /// An interpolated string. InterpolatedString(SmartString), /// `{` LeftBrace, /// `}` RightBrace, /// `(` LeftParen, /// `)` RightParen, /// `[` LeftBracket, /// `]` RightBracket, /// `()` Unit, /// `+` Plus, /// `+` (unary) UnaryPlus, /// `-` Minus, /// `-` (unary) UnaryMinus, /// `*` Multiply, /// `/` Divide, /// `%` Modulo, /// `**` PowerOf, /// `<<` LeftShift, /// `>>` RightShift, /// `;` SemiColon, /// `:` Colon, /// `::` DoubleColon, /// `=>` DoubleArrow, /// `_` Underscore, /// `,` Comma, /// `.` Period, /// `?.` /// /// Reserved under the `no_object` feature. #[cfg(not(feature = "no_object"))] Elvis, /// `??` DoubleQuestion, /// `?[` /// /// Reserved under the `no_object` feature. #[cfg(not(feature = "no_index"))] QuestionBracket, /// `..` ExclusiveRange, /// `..=` InclusiveRange, /// `#{` MapStart, /// `=` Equals, /// `true` True, /// `false` False, /// `let` Let, /// `const` Const, /// `if` If, /// `else` Else, /// `switch` Switch, /// `do` Do, /// `while` While, /// `until` Until, /// `loop` Loop, /// `for` For, /// `in` In, /// `<` LessThan, /// `>` GreaterThan, /// `<=` LessThanEqualsTo, /// `>=` GreaterThanEqualsTo, /// `==` EqualsTo, /// `!=` NotEqualsTo, /// `!` Bang, /// `|` Pipe, /// `||` Or, /// `^` XOr, /// `&` Ampersand, /// `&&` And, /// `fn` /// /// Reserved under the `no_function` feature. #[cfg(not(feature = "no_function"))] Fn, /// `continue` Continue, /// `break` Break, /// `return` Return, /// `throw` Throw, /// `try` Try, /// `catch` Catch, /// `+=` PlusAssign, /// `-=` MinusAssign, /// `*=` MultiplyAssign, /// `/=` DivideAssign, /// `<<=` LeftShiftAssign, /// `>>=` RightShiftAssign, /// `&=` AndAssign, /// `|=` OrAssign, /// `^=` XOrAssign, /// `%=` ModuloAssign, /// `**=` PowerOfAssign, /// `private` /// /// Reserved under the `no_function` feature. #[cfg(not(feature = "no_function"))] Private, /// `import` /// /// Reserved under the `no_module` feature. #[cfg(not(feature = "no_module"))] Import, /// `export` /// /// Reserved under the `no_module` feature. #[cfg(not(feature = "no_module"))] Export, /// `as` /// /// Reserved under the `no_module` feature. #[cfg(not(feature = "no_module"))] As, /// A lexer error. LexError(Box), /// A comment block. Comment(SmartString), /// A reserved symbol. Reserved(SmartString), /// A custom keyword. /// /// Not available under `no_custom_syntax`. #[cfg(not(feature = "no_custom_syntax"))] Custom(SmartString), /// End of the input stream. EOF, } impl fmt::Display for Token { #[inline(always)] fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_str(&self.syntax()) } } impl Token { /// Get the literal syntax of the token. #[must_use] pub const fn literal_syntax(&self) -> &'static str { use Token::*; match self { LeftBrace => "{", RightBrace => "}", LeftParen => "(", RightParen => ")", LeftBracket => "[", RightBracket => "]", Unit => "()", Plus => "+", UnaryPlus => "+", Minus => "-", UnaryMinus => "-", Multiply => "*", Divide => "/", SemiColon => ";", Colon => ":", DoubleColon => "::", DoubleArrow => "=>", Underscore => "_", Comma => ",", Period => ".", #[cfg(not(feature = "no_object"))] Elvis => "?.", DoubleQuestion => "??", #[cfg(not(feature = "no_index"))] QuestionBracket => "?[", ExclusiveRange => "..", InclusiveRange => "..=", MapStart => "#{", Equals => "=", True => "true", False => "false", Let => "let", Const => "const", If => "if", Else => "else", Switch => "switch", Do => "do", While => "while", Until => "until", Loop => "loop", For => "for", In => "in", LessThan => "<", GreaterThan => ">", Bang => "!", LessThanEqualsTo => "<=", GreaterThanEqualsTo => ">=", EqualsTo => "==", NotEqualsTo => "!=", Pipe => "|", Or => "||", Ampersand => "&", And => "&&", Continue => "continue", Break => "break", Return => "return", Throw => "throw", Try => "try", Catch => "catch", PlusAssign => "+=", MinusAssign => "-=", MultiplyAssign => "*=", DivideAssign => "/=", LeftShiftAssign => "<<=", RightShiftAssign => ">>=", AndAssign => "&=", OrAssign => "|=", XOrAssign => "^=", LeftShift => "<<", RightShift => ">>", XOr => "^", Modulo => "%", ModuloAssign => "%=", PowerOf => "**", PowerOfAssign => "**=", #[cfg(not(feature = "no_function"))] Fn => "fn", #[cfg(not(feature = "no_function"))] Private => "private", #[cfg(not(feature = "no_module"))] Import => "import", #[cfg(not(feature = "no_module"))] Export => "export", #[cfg(not(feature = "no_module"))] As => "as", _ => "ERROR: NOT A KEYWORD", } } /// Get the syntax of the token. #[must_use] pub fn syntax(&self) -> Cow<'static, str> { use Token::*; match self { IntegerConstant(i) => i.to_string().into(), #[cfg(not(feature = "no_float"))] FloatConstant(f) => f.to_string().into(), #[cfg(feature = "decimal")] DecimalConstant(d) => d.to_string().into(), StringConstant(..) => "string".into(), InterpolatedString(..) => "string".into(), CharConstant(c) => c.to_string().into(), Identifier(s) => s.to_string().into(), Reserved(s) => s.to_string().into(), #[cfg(not(feature = "no_custom_syntax"))] Custom(s) => s.to_string().into(), LexError(err) => err.to_string().into(), Comment(s) => s.to_string().into(), EOF => "{EOF}".into(), token => token.literal_syntax().into(), } } /// Is this token an op-assignment operator? #[inline] #[must_use] pub const fn is_op_assignment(&self) -> bool { matches!( self, Self::PlusAssign | Self::MinusAssign | Self::MultiplyAssign | Self::DivideAssign | Self::LeftShiftAssign | Self::RightShiftAssign | Self::ModuloAssign | Self::PowerOfAssign | Self::AndAssign | Self::OrAssign | Self::XOrAssign ) } /// Get the corresponding operator of the token if it is an op-assignment operator. #[must_use] pub const fn get_base_op_from_assignment(&self) -> Option { Some(match self { Self::PlusAssign => Self::Plus, Self::MinusAssign => Self::Minus, Self::MultiplyAssign => Self::Multiply, Self::DivideAssign => Self::Divide, Self::LeftShiftAssign => Self::LeftShift, Self::RightShiftAssign => Self::RightShift, Self::ModuloAssign => Self::Modulo, Self::PowerOfAssign => Self::PowerOf, Self::AndAssign => Self::Ampersand, Self::OrAssign => Self::Pipe, Self::XOrAssign => Self::XOr, _ => return None, }) } /// Has this token a corresponding op-assignment operator? #[inline] #[must_use] pub const fn has_op_assignment(&self) -> bool { matches!( self, Self::Plus | Self::Minus | Self::Multiply | Self::Divide | Self::LeftShift | Self::RightShift | Self::Modulo | Self::PowerOf | Self::Ampersand | Self::Pipe | Self::XOr ) } /// Get the corresponding op-assignment operator of the token. #[must_use] pub const fn convert_to_op_assignment(&self) -> Option { Some(match self { Self::Plus => Self::PlusAssign, Self::Minus => Self::MinusAssign, Self::Multiply => Self::MultiplyAssign, Self::Divide => Self::DivideAssign, Self::LeftShift => Self::LeftShiftAssign, Self::RightShift => Self::RightShiftAssign, Self::Modulo => Self::ModuloAssign, Self::PowerOf => Self::PowerOfAssign, Self::Ampersand => Self::AndAssign, Self::Pipe => Self::OrAssign, Self::XOr => Self::XOrAssign, _ => return None, }) } /// Reverse lookup a token from a piece of syntax. #[must_use] pub fn lookup_from_syntax(syntax: &str) -> Option { use Token::*; Some(match syntax { "{" => LeftBrace, "}" => RightBrace, "(" => LeftParen, ")" => RightParen, "[" => LeftBracket, "]" => RightBracket, "()" => Unit, "+" => Plus, "-" => Minus, "*" => Multiply, "/" => Divide, ";" => SemiColon, ":" => Colon, "::" => DoubleColon, "=>" => DoubleArrow, "_" => Underscore, "," => Comma, "." => Period, #[cfg(not(feature = "no_object"))] "?." => Elvis, "??" => DoubleQuestion, #[cfg(not(feature = "no_index"))] "?[" => QuestionBracket, ".." => ExclusiveRange, "..=" => InclusiveRange, "#{" => MapStart, "=" => Equals, "true" => True, "false" => False, "let" => Let, "const" => Const, "if" => If, "else" => Else, "switch" => Switch, "do" => Do, "while" => While, "until" => Until, "loop" => Loop, "for" => For, "in" => In, "<" => LessThan, ">" => GreaterThan, "!" => Bang, "<=" => LessThanEqualsTo, ">=" => GreaterThanEqualsTo, "==" => EqualsTo, "!=" => NotEqualsTo, "|" => Pipe, "||" => Or, "&" => Ampersand, "&&" => And, "continue" => Continue, "break" => Break, "return" => Return, "throw" => Throw, "try" => Try, "catch" => Catch, "+=" => PlusAssign, "-=" => MinusAssign, "*=" => MultiplyAssign, "/=" => DivideAssign, "<<=" => LeftShiftAssign, ">>=" => RightShiftAssign, "&=" => AndAssign, "|=" => OrAssign, "^=" => XOrAssign, "<<" => LeftShift, ">>" => RightShift, "^" => XOr, "%" => Modulo, "%=" => ModuloAssign, "**" => PowerOf, "**=" => PowerOfAssign, #[cfg(feature = "no_object")] "?." => Reserved(syntax.into()), #[cfg(feature = "no_index")] "?[" => Reserved(syntax.into()), #[cfg(not(feature = "no_function"))] "fn" => Fn, #[cfg(not(feature = "no_function"))] "private" => Private, #[cfg(feature = "no_function")] "fn" | "private" => Reserved(syntax.into()), #[cfg(not(feature = "no_module"))] "import" => Import, #[cfg(not(feature = "no_module"))] "export" => Export, #[cfg(not(feature = "no_module"))] "as" => As, #[cfg(feature = "no_module")] "import" | "export" | "as" => Reserved(syntax.into()), // List of reserved operators "===" | "!==" | "->" | "<-" | "?" | ":=" | ":;" | "~" | "!." | "::<" | "(*" | "*)" | "#" | "#!" | "@" | "$" | "++" | "--" | "..." | "<|" | "|>" => Reserved(syntax.into()), // List of reserved keywords "public" | "protected" | "super" | "new" | "use" | "module" | "package" | "var" | "static" | "shared" | "with" | "is" | "goto" | "exit" | "match" | "case" | "default" | "void" | "null" | "nil" | "spawn" | "thread" | "go" | "sync" | "async" | "await" | "yield" => Reserved(syntax.into()), KEYWORD_PRINT | KEYWORD_DEBUG | KEYWORD_TYPE_OF | KEYWORD_EVAL | KEYWORD_FN_PTR | KEYWORD_FN_PTR_CALL | KEYWORD_FN_PTR_CURRY | KEYWORD_THIS | KEYWORD_IS_DEF_VAR => { Reserved(syntax.into()) } #[cfg(not(feature = "no_function"))] crate::engine::KEYWORD_IS_DEF_FN => Reserved(syntax.into()), _ => return None, }) } /// Is this token [`EOF`][Token::EOF]? #[inline(always)] #[must_use] pub const fn is_eof(&self) -> bool { matches!(self, Self::EOF) } /// If another operator is after these, it's probably a unary operator /// (not sure about `fn` name). #[must_use] pub const fn is_next_unary(&self) -> bool { use Token::*; match self { LexError(..) | SemiColon | // ; - is unary Colon | // #{ foo: - is unary Comma | // ( ... , -expr ) - is unary //Period | //Elvis | //DoubleQuestion | //QuestionBracket | ExclusiveRange | // .. - is unary InclusiveRange | // ..= - is unary LeftBrace | // { -expr } - is unary // RightBrace | { expr } - expr not unary & is closing LeftParen | // ( -expr ) - is unary // RightParen | // ( expr ) - expr not unary & is closing LeftBracket | // [ -expr ] - is unary // RightBracket | // [ expr ] - expr not unary & is closing Plus | PlusAssign | UnaryPlus | Minus | MinusAssign | UnaryMinus | Multiply | MultiplyAssign | Divide | DivideAssign | Modulo | ModuloAssign | PowerOf | PowerOfAssign | LeftShift | LeftShiftAssign | RightShift | RightShiftAssign | Equals | EqualsTo | NotEqualsTo | LessThan | GreaterThan | Bang | LessThanEqualsTo | GreaterThanEqualsTo | Pipe | Ampersand | If | //Do | While | Until | In | And | AndAssign | Or | OrAssign | XOr | XOrAssign | Return | Throw => true, _ => false, } } /// Get the precedence number of the token. #[must_use] pub const fn precedence(&self) -> Option { use Token::*; Precedence::new(match self { Or | XOr | Pipe => 30, And | Ampersand => 60, EqualsTo | NotEqualsTo => 90, In => 110, LessThan | LessThanEqualsTo | GreaterThan | GreaterThanEqualsTo => 130, DoubleQuestion => 135, ExclusiveRange | InclusiveRange => 140, Plus | Minus => 150, Divide | Multiply | Modulo => 180, PowerOf => 190, LeftShift | RightShift => 210, _ => 0, }) } /// Does an expression bind to the right (instead of left)? #[must_use] pub const fn is_bind_right(&self) -> bool { use Token::*; match self { // Exponentiation binds to the right PowerOf => true, _ => false, } } /// Is this token a standard symbol used in the language? #[must_use] pub const fn is_standard_symbol(&self) -> bool { use Token::*; match self { LeftBrace | RightBrace | LeftParen | RightParen | LeftBracket | RightBracket | Plus | UnaryPlus | Minus | UnaryMinus | Multiply | Divide | Modulo | PowerOf | LeftShift | RightShift | SemiColon | Colon | DoubleColon | Comma | Period | DoubleQuestion | ExclusiveRange | InclusiveRange | MapStart | Equals | LessThan | GreaterThan | LessThanEqualsTo | GreaterThanEqualsTo | EqualsTo | NotEqualsTo | Bang | Pipe | Or | XOr | Ampersand | And | PlusAssign | MinusAssign | MultiplyAssign | DivideAssign | LeftShiftAssign | RightShiftAssign | AndAssign | OrAssign | XOrAssign | ModuloAssign | PowerOfAssign => true, #[cfg(not(feature = "no_object"))] Elvis => true, #[cfg(not(feature = "no_index"))] QuestionBracket => true, _ => false, } } /// Is this token a standard keyword? #[inline] #[must_use] pub const fn is_standard_keyword(&self) -> bool { use Token::*; match self { #[cfg(not(feature = "no_function"))] Fn | Private => true, #[cfg(not(feature = "no_module"))] Import | Export | As => true, True | False | Let | Const | If | Else | Do | While | Until | Loop | For | In | Continue | Break | Return | Throw | Try | Catch => true, _ => false, } } /// Is this token a reserved keyword or symbol? #[inline(always)] #[must_use] pub const fn is_reserved(&self) -> bool { matches!(self, Self::Reserved(..)) } /// Convert a token into a function name, if possible. #[cfg(not(feature = "no_function"))] #[inline] pub(crate) fn into_function_name_for_override(self) -> Result { match self { #[cfg(not(feature = "no_custom_syntax"))] Self::Custom(s) if is_valid_function_name(&s) => Ok(s), Self::Identifier(s) if is_valid_function_name(&s) => Ok(s), _ => Err(self), } } /// Is this token a custom keyword? #[cfg(not(feature = "no_custom_syntax"))] #[inline(always)] #[must_use] pub const fn is_custom(&self) -> bool { matches!(self, Self::Custom(..)) } } impl From for String { #[inline(always)] fn from(token: Token) -> Self { token.syntax().into() } } /// _(internals)_ State of the tokenizer. /// Exported under the `internals` feature only. #[derive(Debug, Clone, Eq, PartialEq, Default)] pub struct TokenizeState { /// Maximum length of a string. pub max_string_size: Option, /// Can the next token be a unary operator? pub next_token_cannot_be_unary: bool, /// Shared object to allow controlling the tokenizer externally. pub tokenizer_control: TokenizerControl, /// Is the tokenizer currently inside a block comment? pub comment_level: usize, /// Include comments? pub include_comments: bool, /// Is the current tokenizer position within the text stream of an interpolated string? pub is_within_text_terminated_by: Option, } /// _(internals)_ Trait that encapsulates a peekable character input stream. /// Exported under the `internals` feature only. pub trait InputStream { /// Un-get a character back into the `InputStream`. /// The next [`get_next`][InputStream::get_next] or [`peek_next`][InputStream::peek_next] /// will return this character instead. fn unget(&mut self, ch: char); /// Get the next character from the `InputStream`. fn get_next(&mut self) -> Option; /// Peek the next character in the `InputStream`. #[must_use] fn peek_next(&mut self) -> Option; } /// _(internals)_ Parse a string literal ended by a specified termination character. /// Exported under the `internals` feature only. /// /// Returns the parsed string and a boolean indicating whether the string is /// terminated by an interpolation `${`. /// /// # Returns /// /// | Type | Return Value |`state.is_within_text_terminated_by`| /// |---------------------------------|:--------------------------:|:----------------------------------:| /// |`"hello"` |`StringConstant("hello")` |`None` | /// |`"hello`_{LF}_ or _{EOF}_ |`LexError` |`None` | /// |`"hello\`_{EOF}_ or _{LF}{EOF}_ |`StringConstant("hello")` |`Some('"')` | /// |`` `hello``_{EOF}_ |`StringConstant("hello")` |``Some('`')`` | /// |`` `hello``_{LF}{EOF}_ |`StringConstant("hello\n")` |``Some('`')`` | /// |`` `hello ${`` |`InterpolatedString("hello ")`
next token is `{`|`None` | /// |`` } hello` `` |`StringConstant(" hello")` |`None` | /// |`} hello`_{EOF}_ |`StringConstant(" hello")` |``Some('`')`` | /// /// This function does not throw a `LexError` for the following conditions: /// /// * Unterminated literal string at _{EOF}_ /// /// * Unterminated normal string with continuation at _{EOF}_ /// /// This is to facilitate using this function to parse a script line-by-line, where the end of the /// line (i.e. _{EOF}_) is not necessarily the end of the script. /// /// Any time a [`StringConstant`][`Token::StringConstant`] is returned with /// `state.is_within_text_terminated_by` set to `Some(_)` is one of the above conditions. pub fn parse_string_literal( stream: &mut impl InputStream, state: &mut TokenizeState, pos: &mut Position, termination_char: char, verbatim: bool, allow_line_continuation: bool, allow_interpolation: bool, ) -> Result<(SmartString, bool, Position), (LexError, Position)> { let mut result = SmartString::new_const(); let mut escape = SmartString::new_const(); let start = *pos; let mut first_char = Position::NONE; let mut interpolated = false; #[cfg(not(feature = "no_position"))] let mut skip_whitespace_until = 0; state.is_within_text_terminated_by = Some(termination_char); loop { assert!( !verbatim || escape.is_empty(), "verbatim strings should not have any escapes" ); let next_char = match stream.get_next() { Some(ch) => { pos.advance(); ch } None if verbatim => { assert_eq!(escape, "", "verbatim strings should not have any escapes"); pos.advance(); break; } None if allow_line_continuation && !escape.is_empty() => { assert_eq!(escape, "\\", "unexpected escape {} at end of line", escape); pos.advance(); break; } None => { pos.advance(); state.is_within_text_terminated_by = None; return Err((LERR::UnterminatedString, start)); } }; // String interpolation? if allow_interpolation && next_char == '$' && escape.is_empty() && stream.peek_next().map_or(false, |ch| ch == '{') { interpolated = true; state.is_within_text_terminated_by = None; break; } if let Some(max) = state.max_string_size { if result.len() > max.get() { return Err((LexError::StringTooLong(max.get()), *pos)); } } // Close wrapper if termination_char == next_char && escape.is_empty() { // Double wrapper if stream.peek_next().map_or(false, |c| c == termination_char) { eat_next(stream, pos); } else { state.is_within_text_terminated_by = None; break; } } if first_char.is_none() { first_char = *pos; } match next_char { // \r - ignore if followed by \n '\r' if stream.peek_next().map_or(false, |ch| ch == '\n') => (), // \... '\\' if !verbatim && escape.is_empty() => { escape.push('\\'); } // \\ '\\' if !escape.is_empty() => { escape.clear(); result.push('\\'); } // \t 't' if !escape.is_empty() => { escape.clear(); result.push('\t'); } // \n 'n' if !escape.is_empty() => { escape.clear(); result.push('\n'); } // \r 'r' if !escape.is_empty() => { escape.clear(); result.push('\r'); } // \x??, \u????, \U???????? ch @ ('x' | 'u' | 'U') if !escape.is_empty() => { let mut seq = escape.clone(); escape.clear(); seq.push(ch); let mut out_val: u32 = 0; let len = match ch { 'x' => 2, 'u' => 4, 'U' => 8, c => unreachable!("x or u or U expected but gets '{}'", c), }; for _ in 0..len { let c = stream .get_next() .ok_or_else(|| (LERR::MalformedEscapeSequence(seq.to_string()), *pos))?; seq.push(c); pos.advance(); out_val *= 16; out_val += c .to_digit(16) .ok_or_else(|| (LERR::MalformedEscapeSequence(seq.to_string()), *pos))?; } result.push( char::from_u32(out_val) .ok_or_else(|| (LERR::MalformedEscapeSequence(seq.to_string()), *pos))?, ); } // \{termination_char} - escaped _ if termination_char == next_char && !escape.is_empty() => { escape.clear(); result.push(next_char); } // Verbatim '\n' if verbatim => { assert_eq!(escape, "", "verbatim strings should not have any escapes"); pos.new_line(); result.push(next_char); } // Line continuation '\n' if allow_line_continuation && !escape.is_empty() => { assert_eq!(escape, "\\", "unexpected escape {} at end of line", escape); escape.clear(); pos.new_line(); #[cfg(not(feature = "no_position"))] { let start_position = start.position().unwrap(); skip_whitespace_until = start_position + 1; } } // Unterminated string '\n' => { pos.rewind(); state.is_within_text_terminated_by = None; return Err((LERR::UnterminatedString, start)); } // Unknown escape sequence _ if !escape.is_empty() => { escape.push(next_char); return Err((LERR::MalformedEscapeSequence(escape.to_string()), *pos)); } // Whitespace to skip #[cfg(not(feature = "no_position"))] _ if next_char.is_whitespace() && pos.position().unwrap() < skip_whitespace_until => {} // All other characters _ => { escape.clear(); result.push(next_char); #[cfg(not(feature = "no_position"))] { skip_whitespace_until = 0; } } } } if let Some(max) = state.max_string_size { if result.len() > max.get() { return Err((LexError::StringTooLong(max.get()), *pos)); } } Ok((result, interpolated, first_char)) } /// Consume the next character. #[inline(always)] fn eat_next(stream: &mut impl InputStream, pos: &mut Position) -> Option { pos.advance(); stream.get_next() } /// Scan for a block comment until the end. fn scan_block_comment( stream: &mut impl InputStream, level: usize, pos: &mut Position, comment: Option<&mut SmartString>, ) -> usize { let mut level = level; let mut comment = comment; while let Some(c) = stream.get_next() { pos.advance(); if let Some(comment) = comment.as_mut() { comment.push(c); } match c { '/' => { if let Some(c2) = stream.peek_next().filter(|&c2| c2 == '*') { eat_next(stream, pos); if let Some(comment) = comment.as_mut() { comment.push(c2); } level += 1; } } '*' => { if let Some(c2) = stream.peek_next().filter(|&c2| c2 == '/') { eat_next(stream, pos); if let Some(comment) = comment.as_mut() { comment.push(c2); } level -= 1; } } '\n' => pos.new_line(), _ => (), } if level == 0 { break; } } level } /// _(internals)_ Get the next token from the input stream. /// Exported under the `internals` feature only. #[inline] #[must_use] pub fn get_next_token( stream: &mut impl InputStream, state: &mut TokenizeState, pos: &mut Position, ) -> Option<(Token, Position)> { let result = get_next_token_inner(stream, state, pos); // Save the last token's state if let Some((ref token, ..)) = result { state.next_token_cannot_be_unary = !token.is_next_unary(); } result } /// Test if the given character is a hex character. #[inline(always)] fn is_hex_digit(c: char) -> bool { matches!(c, 'a'..='f' | 'A'..='F' | '0'..='9') } /// Test if the given character is a numeric digit. #[inline(always)] fn is_numeric_digit(c: char) -> bool { matches!(c, '0'..='9') } /// Test if the comment block is a doc-comment. #[cfg(not(feature = "no_function"))] #[cfg(feature = "metadata")] #[inline] #[must_use] pub fn is_doc_comment(comment: &str) -> bool { (comment.starts_with("///") && !comment.starts_with("////")) || (comment.starts_with("/**") && !comment.starts_with("/***")) } /// Get the next token. #[must_use] fn get_next_token_inner( stream: &mut impl InputStream, state: &mut TokenizeState, pos: &mut Position, ) -> Option<(Token, Position)> { // Still inside a comment? if state.comment_level > 0 { let start_pos = *pos; let mut comment = if state.include_comments { Some(SmartString::new_const()) } else { None }; state.comment_level = scan_block_comment(stream, state.comment_level, pos, comment.as_mut()); let return_comment = state.include_comments; #[cfg(not(feature = "no_function"))] #[cfg(feature = "metadata")] let return_comment = return_comment || is_doc_comment(comment.as_ref().expect("`Some`")); if return_comment { return Some((Token::Comment(comment.expect("`Some`")), start_pos)); } if state.comment_level > 0 { // Reached EOF without ending comment block return None; } } // Within text? if let Some(ch) = state.is_within_text_terminated_by.take() { return parse_string_literal(stream, state, pos, ch, true, false, true).map_or_else( |(err, err_pos)| Some((Token::LexError(err.into()), err_pos)), |(result, interpolated, start_pos)| { if interpolated { Some((Token::InterpolatedString(result), start_pos)) } else { Some((Token::StringConstant(result), start_pos)) } }, ); } let mut negated: Option = None; while let Some(c) = stream.get_next() { pos.advance(); let start_pos = *pos; match (c, stream.peek_next().unwrap_or('\0')) { // \n ('\n', ..) => pos.new_line(), // digit ... ('0'..='9', ..) => { let mut result = SmartString::new_const(); let mut radix_base: Option = None; let mut valid: fn(char) -> bool = is_numeric_digit; result.push(c); while let Some(next_char) = stream.peek_next() { match next_char { NUMBER_SEPARATOR => { eat_next(stream, pos); } ch if valid(ch) => { result.push(next_char); eat_next(stream, pos); } #[cfg(any(not(feature = "no_float"), feature = "decimal"))] '.' => { stream.get_next().unwrap(); // Check if followed by digits or something that cannot start a property name match stream.peek_next().unwrap_or('\0') { // digits after period - accept the period '0'..='9' => { result.push(next_char); pos.advance(); } // _ - cannot follow a decimal point '_' => { stream.unget(next_char); break; } // .. - reserved symbol, not a floating-point number '.' => { stream.unget(next_char); break; } // symbol after period - probably a float ch if !is_id_first_alphabetic(ch) => { result.push(next_char); pos.advance(); result.push('0'); } // Not a floating-point number _ => { stream.unget(next_char); break; } } } #[cfg(not(feature = "no_float"))] 'e' => { stream.get_next().expect("`e`"); // Check if followed by digits or +/- match stream.peek_next().unwrap_or('\0') { // digits after e - accept the e '0'..='9' => { result.push(next_char); pos.advance(); } // +/- after e - accept the e and the sign '+' | '-' => { result.push(next_char); pos.advance(); result.push(stream.get_next().unwrap()); pos.advance(); } // Not a floating-point number _ => { stream.unget(next_char); break; } } } // 0x????, 0o????, 0b???? at beginning ch @ ('x' | 'o' | 'b' | 'X' | 'O' | 'B') if c == '0' && result.len() <= 1 => { result.push(next_char); eat_next(stream, pos); valid = match ch { 'x' | 'X' => is_hex_digit, 'o' | 'O' => is_numeric_digit, 'b' | 'B' => is_numeric_digit, c => unreachable!("x/X or o/O or b/B expected but gets '{}'", c), }; radix_base = Some(match ch { 'x' | 'X' => 16, 'o' | 'O' => 8, 'b' | 'B' => 2, c => unreachable!("x/X or o/O or b/B expected but gets '{}'", c), }); } _ => break, } } let num_pos = negated.map_or(start_pos, |negated_pos| { result.insert(0, '-'); negated_pos }); // Parse number return Some(( if let Some(radix) = radix_base { let result = &result[2..]; UNSIGNED_INT::from_str_radix(&result, radix) .map(|v| v as INT) .map_or_else( |_| { Token::LexError( LERR::MalformedNumber(result.to_string()).into(), ) }, Token::IntegerConstant, ) } else { let num = INT::from_str(&result).map(Token::IntegerConstant); // If integer parsing is unnecessary, try float instead #[cfg(not(feature = "no_float"))] let num = num.or_else(|_| { crate::ast::FloatWrapper::from_str(&result).map(Token::FloatConstant) }); // Then try decimal #[cfg(feature = "decimal")] let num = num.or_else(|_| { rust_decimal::Decimal::from_str(&result).map(Token::DecimalConstant) }); // Then try decimal in scientific notation #[cfg(feature = "decimal")] let num = num.or_else(|_| { rust_decimal::Decimal::from_scientific(&result) .map(Token::DecimalConstant) }); num.unwrap_or_else(|_| { Token::LexError(LERR::MalformedNumber(result.to_string()).into()) }) }, num_pos, )); } // letter or underscore ... #[cfg(not(feature = "unicode-xid-ident"))] ('a'..='z' | '_' | 'A'..='Z', ..) => { return Some(get_identifier(stream, pos, start_pos, c)); } #[cfg(feature = "unicode-xid-ident")] (ch, ..) if unicode_xid::UnicodeXID::is_xid_start(ch) || ch == '_' => { return Some(get_identifier(stream, pos, start_pos, c)); } // " - string literal ('"', ..) => { return parse_string_literal(stream, state, pos, c, false, true, false) .map_or_else( |(err, err_pos)| Some((Token::LexError(err.into()), err_pos)), |(result, ..)| Some((Token::StringConstant(result), start_pos)), ); } // ` - string literal ('`', ..) => { // Start from the next line if at the end of line match stream.peek_next() { // `\r - start from next line Some('\r') => { eat_next(stream, pos); // `\r\n if let Some('\n') = stream.peek_next() { eat_next(stream, pos); } pos.new_line(); } // `\n - start from next line Some('\n') => { eat_next(stream, pos); pos.new_line(); } _ => (), } return parse_string_literal(stream, state, pos, c, true, false, true).map_or_else( |(err, err_pos)| Some((Token::LexError(err.into()), err_pos)), |(result, interpolated, ..)| { if interpolated { Some((Token::InterpolatedString(result), start_pos)) } else { Some((Token::StringConstant(result), start_pos)) } }, ); } // ' - character literal ('\'', '\'') => { return Some(( Token::LexError(LERR::MalformedChar("".to_string()).into()), start_pos, )) } ('\'', ..) => { return Some( parse_string_literal(stream, state, pos, c, false, false, false).map_or_else( |(err, err_pos)| (Token::LexError(err.into()), err_pos), |(result, ..)| { let mut chars = result.chars(); let first = chars.next().unwrap(); if chars.next().is_some() { ( Token::LexError(LERR::MalformedChar(result.to_string()).into()), start_pos, ) } else { (Token::CharConstant(first), start_pos) } }, ), ) } // Braces ('{', ..) => return Some((Token::LeftBrace, start_pos)), ('}', ..) => return Some((Token::RightBrace, start_pos)), // Unit ('(', ')') => { eat_next(stream, pos); return Some((Token::Unit, start_pos)); } // Parentheses ('(', '*') => { eat_next(stream, pos); return Some((Token::Reserved("(*".into()), start_pos)); } ('(', ..) => return Some((Token::LeftParen, start_pos)), (')', ..) => return Some((Token::RightParen, start_pos)), // Indexing ('[', ..) => return Some((Token::LeftBracket, start_pos)), (']', ..) => return Some((Token::RightBracket, start_pos)), // Map literal #[cfg(not(feature = "no_object"))] ('#', '{') => { eat_next(stream, pos); return Some((Token::MapStart, start_pos)); } // Shebang ('#', '!') => return Some((Token::Reserved("#!".into()), start_pos)), ('#', ' ') => { eat_next(stream, pos); let token = if stream.peek_next() == Some('{') { eat_next(stream, pos); "# {" } else { "#" }; return Some((Token::Reserved(token.into()), start_pos)); } ('#', ..) => return Some((Token::Reserved("#".into()), start_pos)), // Operators ('+', '=') => { eat_next(stream, pos); return Some((Token::PlusAssign, start_pos)); } ('+', '+') => { eat_next(stream, pos); return Some((Token::Reserved("++".into()), start_pos)); } ('+', ..) if !state.next_token_cannot_be_unary => { return Some((Token::UnaryPlus, start_pos)) } ('+', ..) => return Some((Token::Plus, start_pos)), ('-', '0'..='9') if !state.next_token_cannot_be_unary => negated = Some(start_pos), ('-', '0'..='9') => return Some((Token::Minus, start_pos)), ('-', '=') => { eat_next(stream, pos); return Some((Token::MinusAssign, start_pos)); } ('-', '>') => { eat_next(stream, pos); return Some((Token::Reserved("->".into()), start_pos)); } ('-', '-') => { eat_next(stream, pos); return Some((Token::Reserved("--".into()), start_pos)); } ('-', ..) if !state.next_token_cannot_be_unary => { return Some((Token::UnaryMinus, start_pos)) } ('-', ..) => return Some((Token::Minus, start_pos)), ('*', ')') => { eat_next(stream, pos); return Some((Token::Reserved("*)".into()), start_pos)); } ('*', '=') => { eat_next(stream, pos); return Some((Token::MultiplyAssign, start_pos)); } ('*', '*') => { eat_next(stream, pos); return Some(( if stream.peek_next() == Some('=') { eat_next(stream, pos); Token::PowerOfAssign } else { Token::PowerOf }, start_pos, )); } ('*', ..) => return Some((Token::Multiply, start_pos)), // Comments ('/', '/') => { eat_next(stream, pos); let mut comment: Option = match stream.peek_next() { #[cfg(not(feature = "no_function"))] #[cfg(feature = "metadata")] Some('/') => { eat_next(stream, pos); // Long streams of `///...` are not doc-comments match stream.peek_next() { Some('/') => None, _ => Some("///".into()), } } #[cfg(feature = "metadata")] Some('!') => { eat_next(stream, pos); Some("//!".into()) } _ if state.include_comments => Some("//".into()), _ => None, }; while let Some(c) = stream.get_next() { if c == '\r' { // \r\n if let Some('\n') = stream.peek_next() { eat_next(stream, pos); } pos.new_line(); break; } if c == '\n' { pos.new_line(); break; } if let Some(comment) = comment.as_mut() { comment.push(c); } pos.advance(); } if let Some(comment) = comment { match comment { #[cfg(feature = "metadata")] _ if comment.starts_with("//!") => state .tokenizer_control .borrow_mut() .global_comments .push(comment), _ => return Some((Token::Comment(comment), start_pos)), } } } ('/', '*') => { state.comment_level = 1; eat_next(stream, pos); let mut comment: Option = match stream.peek_next() { #[cfg(not(feature = "no_function"))] #[cfg(feature = "metadata")] Some('*') => { eat_next(stream, pos); // Long streams of `/****...` are not doc-comments match stream.peek_next() { Some('*') => None, _ => Some("/**".into()), } } _ if state.include_comments => Some("/*".into()), _ => None, }; state.comment_level = scan_block_comment(stream, state.comment_level, pos, comment.as_mut()); if let Some(comment) = comment { return Some((Token::Comment(comment), start_pos)); } } ('/', '=') => { eat_next(stream, pos); return Some((Token::DivideAssign, start_pos)); } ('/', ..) => return Some((Token::Divide, start_pos)), (';', ..) => return Some((Token::SemiColon, start_pos)), (',', ..) => return Some((Token::Comma, start_pos)), ('.', '.') => { eat_next(stream, pos); return Some(( match stream.peek_next() { Some('.') => { eat_next(stream, pos); Token::Reserved("...".into()) } Some('=') => { eat_next(stream, pos); Token::InclusiveRange } _ => Token::ExclusiveRange, }, start_pos, )); } ('.', ..) => return Some((Token::Period, start_pos)), ('=', '=') => { eat_next(stream, pos); if stream.peek_next() == Some('=') { eat_next(stream, pos); return Some((Token::Reserved("===".into()), start_pos)); } return Some((Token::EqualsTo, start_pos)); } ('=', '>') => { eat_next(stream, pos); return Some((Token::DoubleArrow, start_pos)); } ('=', ..) => return Some((Token::Equals, start_pos)), #[cfg(not(feature = "no_module"))] (':', ':') => { eat_next(stream, pos); if stream.peek_next() == Some('<') { eat_next(stream, pos); return Some((Token::Reserved("::<".into()), start_pos)); } return Some((Token::DoubleColon, start_pos)); } (':', '=') => { eat_next(stream, pos); return Some((Token::Reserved(":=".into()), start_pos)); } (':', ';') => { eat_next(stream, pos); return Some((Token::Reserved(":;".into()), start_pos)); } (':', ..) => return Some((Token::Colon, start_pos)), ('<', '=') => { eat_next(stream, pos); return Some((Token::LessThanEqualsTo, start_pos)); } ('<', '-') => { eat_next(stream, pos); return Some((Token::Reserved("<-".into()), start_pos)); } ('<', '<') => { eat_next(stream, pos); return Some(( if stream.peek_next() == Some('=') { eat_next(stream, pos); Token::LeftShiftAssign } else { Token::LeftShift }, start_pos, )); } ('<', '|') => { eat_next(stream, pos); return Some((Token::Reserved("<|".into()), start_pos)); } ('<', ..) => return Some((Token::LessThan, start_pos)), ('>', '=') => { eat_next(stream, pos); return Some((Token::GreaterThanEqualsTo, start_pos)); } ('>', '>') => { eat_next(stream, pos); return Some(( if stream.peek_next() == Some('=') { eat_next(stream, pos); Token::RightShiftAssign } else { Token::RightShift }, start_pos, )); } ('>', ..) => return Some((Token::GreaterThan, start_pos)), ('!', '=') => { eat_next(stream, pos); if stream.peek_next() == Some('=') { eat_next(stream, pos); return Some((Token::Reserved("!==".into()), start_pos)); } return Some((Token::NotEqualsTo, start_pos)); } ('!', '.') => { eat_next(stream, pos); return Some((Token::Reserved("!.".into()), start_pos)); } ('!', ..) => return Some((Token::Bang, start_pos)), ('|', '|') => { eat_next(stream, pos); return Some((Token::Or, start_pos)); } ('|', '=') => { eat_next(stream, pos); return Some((Token::OrAssign, start_pos)); } ('|', '>') => { eat_next(stream, pos); return Some((Token::Reserved("|>".into()), start_pos)); } ('|', ..) => return Some((Token::Pipe, start_pos)), ('&', '&') => { eat_next(stream, pos); return Some((Token::And, start_pos)); } ('&', '=') => { eat_next(stream, pos); return Some((Token::AndAssign, start_pos)); } ('&', ..) => return Some((Token::Ampersand, start_pos)), ('^', '=') => { eat_next(stream, pos); return Some((Token::XOrAssign, start_pos)); } ('^', ..) => return Some((Token::XOr, start_pos)), ('~', ..) => return Some((Token::Reserved("~".into()), start_pos)), ('%', '=') => { eat_next(stream, pos); return Some((Token::ModuloAssign, start_pos)); } ('%', ..) => return Some((Token::Modulo, start_pos)), ('@', ..) => return Some((Token::Reserved("@".into()), start_pos)), ('$', ..) => return Some((Token::Reserved("$".into()), start_pos)), ('?', '.') => { eat_next(stream, pos); return Some(( #[cfg(not(feature = "no_object"))] Token::Elvis, #[cfg(feature = "no_object")] Token::Reserved("?.".into()), start_pos, )); } ('?', '?') => { eat_next(stream, pos); return Some((Token::DoubleQuestion, start_pos)); } ('?', '[') => { eat_next(stream, pos); return Some(( #[cfg(not(feature = "no_index"))] Token::QuestionBracket, #[cfg(feature = "no_index")] Token::Reserved("?[".into()), start_pos, )); } ('?', ..) => return Some((Token::Reserved("?".into()), start_pos)), (ch, ..) if ch.is_whitespace() => (), (ch, ..) => { return Some(( Token::LexError(LERR::UnexpectedInput(ch.to_string()).into()), start_pos, )) } } } pos.advance(); Some((Token::EOF, *pos)) } /// Get the next identifier. fn get_identifier( stream: &mut impl InputStream, pos: &mut Position, start_pos: Position, first_char: char, ) -> (Token, Position) { let mut identifier = SmartString::new_const(); identifier.push(first_char); while let Some(next_char) = stream.peek_next() { match next_char { x if is_id_continue(x) => { identifier.push(x); eat_next(stream, pos); } _ => break, } } let is_valid_identifier = is_valid_identifier(identifier.chars()); if let Some(token) = Token::lookup_from_syntax(&identifier) { return (token, start_pos); } if !is_valid_identifier { return ( Token::LexError(LERR::MalformedIdentifier(identifier.to_string()).into()), start_pos, ); } (Token::Identifier(identifier), start_pos) } /// Is a keyword allowed as a function? #[inline] #[must_use] pub fn is_keyword_function(name: &str) -> bool { match name { KEYWORD_PRINT | KEYWORD_DEBUG | KEYWORD_TYPE_OF | KEYWORD_EVAL | KEYWORD_FN_PTR | KEYWORD_FN_PTR_CALL | KEYWORD_FN_PTR_CURRY | KEYWORD_IS_DEF_VAR => true, #[cfg(not(feature = "no_function"))] crate::engine::KEYWORD_IS_DEF_FN => true, _ => false, } } /// _(internals)_ Is a text string a valid identifier? /// Exported under the `internals` feature only. #[must_use] pub fn is_valid_identifier(name: impl Iterator) -> bool { let mut first_alphabetic = false; for ch in name { match ch { '_' => (), _ if is_id_first_alphabetic(ch) => first_alphabetic = true, _ if !first_alphabetic => return false, _ if char::is_ascii_alphanumeric(&ch) => (), _ => return false, } } first_alphabetic } /// _(internals)_ Is a text string a valid script-defined function name? /// Exported under the `internals` feature only. #[inline(always)] #[must_use] pub fn is_valid_function_name(name: &str) -> bool { is_valid_identifier(name.chars()) } /// Is a character valid to start an identifier? #[cfg(feature = "unicode-xid-ident")] #[inline(always)] #[must_use] pub fn is_id_first_alphabetic(x: char) -> bool { unicode_xid::UnicodeXID::is_xid_start(x) } /// Is a character valid for an identifier? #[cfg(feature = "unicode-xid-ident")] #[inline(always)] #[must_use] pub fn is_id_continue(x: char) -> bool { unicode_xid::UnicodeXID::is_xid_continue(x) } /// Is a character valid to start an identifier? #[cfg(not(feature = "unicode-xid-ident"))] #[inline(always)] #[must_use] pub const fn is_id_first_alphabetic(x: char) -> bool { x.is_ascii_alphabetic() } /// Is a character valid for an identifier? #[cfg(not(feature = "unicode-xid-ident"))] #[inline(always)] #[must_use] pub const fn is_id_continue(x: char) -> bool { x.is_ascii_alphanumeric() || x == '_' } /// _(internals)_ A type that implements the [`InputStream`] trait. /// Exported under the `internals` feature only. /// /// Multiple character streams are jointed together to form one single stream. pub struct MultiInputsStream<'a> { /// Buffered character, if any. pub buf: Option, /// The current stream index. pub index: usize, /// The input character streams. pub streams: StaticVec>>, } impl InputStream for MultiInputsStream<'_> { #[inline] fn unget(&mut self, ch: char) { if self.buf.is_some() { panic!("cannot unget two characters in a row"); } self.buf = Some(ch); } fn get_next(&mut self) -> Option { if let Some(ch) = self.buf.take() { return Some(ch); } loop { if self.index >= self.streams.len() { // No more streams return None; } if let Some(ch) = self.streams[self.index].next() { // Next character in current stream return Some(ch); } // Jump to the next stream self.index += 1; } } fn peek_next(&mut self) -> Option { if let Some(ch) = self.buf { return Some(ch); } loop { if self.index >= self.streams.len() { // No more streams return None; } if let Some(&ch) = self.streams[self.index].peek() { // Next character in current stream return Some(ch); } // Jump to the next stream self.index += 1; } } } /// _(internals)_ An iterator on a [`Token`] stream. /// Exported under the `internals` feature only. pub struct TokenIterator<'a> { /// Reference to the scripting `Engine`. pub engine: &'a Engine, /// Current state. pub state: TokenizeState, /// Current position. pub pos: Position, /// Input character stream. pub stream: MultiInputsStream<'a>, /// A processor function that maps a token to another. pub token_mapper: Option<&'a OnParseTokenCallback>, } impl<'a> Iterator for TokenIterator<'a> { type Item = (Token, Position); fn next(&mut self) -> Option { { let control = &mut *self.state.tokenizer_control.borrow_mut(); if control.is_within_text { // Switch to text mode terminated by back-tick self.state.is_within_text_terminated_by = Some('`'); // Reset it control.is_within_text = false; } } let (token, pos) = match get_next_token(&mut self.stream, &mut self.state, &mut self.pos) { // {EOF} None => return None, // {EOF} after unterminated string. // The only case where `TokenizeState.is_within_text_terminated_by` is set is when // a verbatim string or a string with continuation encounters {EOF}. // This is necessary to handle such cases for line-by-line parsing, but for an entire // script it is a syntax error. Some((Token::StringConstant(..), pos)) if self.state.is_within_text_terminated_by.is_some() => { self.state.is_within_text_terminated_by = None; return Some((Token::LexError(LERR::UnterminatedString.into()), pos)); } // Reserved keyword/symbol Some((Token::Reserved(s), pos)) => (match (&*s, #[cfg(not(feature = "no_custom_syntax"))] (!self.engine.custom_keywords.is_empty() && self.engine.custom_keywords.contains_key(&*s)), #[cfg(feature = "no_custom_syntax")] false ) { ("===", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(), "'===' is not a valid operator. This is not JavaScript! Should it be '=='?".to_string(), ).into()), ("!==", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(), "'!==' is not a valid operator. This is not JavaScript! Should it be '!='?".to_string(), ).into()), ("->", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(), "'->' is not a valid symbol. This is not C or C++!".to_string()).into()), ("<-", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(), "'<-' is not a valid symbol. This is not Go! Should it be '<='?".to_string(), ).into()), (":=", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(), "':=' is not a valid assignment operator. This is not Go or Pascal! Should it be simply '='?".to_string(), ).into()), (":;", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(), "':;' is not a valid symbol. Should it be '::'?".to_string(), ).into()), ("::<", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(), "'::<>' is not a valid symbol. This is not Rust! Should it be '::'?".to_string(), ).into()), ("(*" | "*)", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(), "'(* .. *)' is not a valid comment format. This is not Pascal! Should it be '/* .. */'?".to_string(), ).into()), ("# {", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(), "'#' is not a valid symbol. Should it be '#{'?".to_string(), ).into()), // Reserved keyword/operator that is custom. #[cfg(not(feature = "no_custom_syntax"))] (.., true) => Token::Custom(s), #[cfg(feature = "no_custom_syntax")] (.., true) => unreachable!("no custom operators"), // Reserved keyword that is not custom and disabled. (token, false) if !self.engine.disabled_symbols.is_empty() && self.engine.disabled_symbols.contains(token) => { let msg = format!("reserved {} '{token}' is disabled", if is_valid_identifier(token.chars()) { "keyword"} else {"symbol"}); Token::LexError(LERR::ImproperSymbol(s.to_string(), msg).into()) }, // Reserved keyword/operator that is not custom. (.., false) => Token::Reserved(s), }, pos), // Custom keyword #[cfg(not(feature = "no_custom_syntax"))] Some((Token::Identifier(s), pos)) if !self.engine.custom_keywords.is_empty() && self.engine.custom_keywords.contains_key(&*s) => { (Token::Custom(s), pos) } // Custom keyword/symbol - must be disabled #[cfg(not(feature = "no_custom_syntax"))] Some((token, pos)) if !self.engine.custom_keywords.is_empty() && self.engine.custom_keywords.contains_key(token.literal_syntax()) => { if !self.engine.disabled_symbols.is_empty() && self.engine.disabled_symbols.contains(token.literal_syntax()) { // Disabled standard keyword/symbol (Token::Custom(token.literal_syntax().into()), pos) } else { // Active standard keyword - should never be a custom keyword! unreachable!("{:?} is an active keyword", token) } } // Disabled symbol Some((token, pos)) if !self.engine.disabled_symbols.is_empty() && self.engine.disabled_symbols.contains(token.literal_syntax()) => { (Token::Reserved(token.literal_syntax().into()), pos) } // Normal symbol Some(r) => r, }; // Run the mapper, if any let token = match self.token_mapper { Some(map_func) => map_func(token, pos, &self.state), None => token, }; Some((token, pos)) } } impl FusedIterator for TokenIterator<'_> {} impl Engine { /// _(internals)_ Tokenize an input text stream. /// Exported under the `internals` feature only. #[cfg(feature = "internals")] #[inline(always)] #[must_use] pub fn lex<'a>( &'a self, input: impl IntoIterator + 'a)>, ) -> (TokenIterator<'a>, TokenizerControl) { self.lex_raw(input, None) } /// _(internals)_ Tokenize an input text stream with a mapping function. /// Exported under the `internals` feature only. #[cfg(feature = "internals")] #[inline(always)] #[must_use] pub fn lex_with_map<'a>( &'a self, input: impl IntoIterator + 'a)>, token_mapper: &'a OnParseTokenCallback, ) -> (TokenIterator<'a>, TokenizerControl) { self.lex_raw(input, Some(token_mapper)) } /// Tokenize an input text stream with an optional mapping function. #[inline] #[must_use] pub(crate) fn lex_raw<'a>( &'a self, input: impl IntoIterator + 'a)>, token_mapper: Option<&'a OnParseTokenCallback>, ) -> (TokenIterator<'a>, TokenizerControl) { let buffer: TokenizerControl = RefCell::new(TokenizerControlBlock::new()).into(); let buffer2 = buffer.clone(); ( TokenIterator { engine: self, state: TokenizeState { #[cfg(not(feature = "unchecked"))] max_string_size: self.limits.max_string_size, #[cfg(feature = "unchecked")] max_string_size: None, next_token_cannot_be_unary: false, tokenizer_control: buffer, comment_level: 0, include_comments: false, is_within_text_terminated_by: None, }, pos: Position::new(1, 0), stream: MultiInputsStream { buf: None, streams: input .into_iter() .map(|s| s.as_ref().chars().peekable()) .collect(), index: 0, }, token_mapper, }, buffer2, ) } }