564 lines
17 KiB
Rust
564 lines
17 KiB
Rust
#![feature(slice_swap_unchecked, iter_collect_into)]
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mod is_things {
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/// True if `c` is considered a whitespace according to Rust language definition.
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/// See [Rust language reference](https://doc.rust-lang.org/reference/whitespace.html)
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/// for definitions of these classes.
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pub fn is_whitespace(c: char) -> bool {
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// This is Pattern_White_Space.
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//
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// Note that this set is stable (ie, it doesn't change with different
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// Unicode versions), so it's ok to just hard-code the values.
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matches!(
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c,
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// Usual ASCII suspects
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'\u{0009}' // \t
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| '\u{000A}' // \n
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| '\u{000B}' // vertical tab
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| '\u{000C}' // form feed
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| '\u{000D}' // \r
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| '\u{0020}' // space
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// NEXT LINE from latin1
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| '\u{0085}'
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// Bidi markers
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| '\u{200E}' // LEFT-TO-RIGHT MARK
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| '\u{200F}' // RIGHT-TO-LEFT MARK
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// Dedicated whitespace characters from Unicode
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| '\u{2028}' // LINE SEPARATOR
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| '\u{2029}' // PARAGRAPH SEPARATOR
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)
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}
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/// True if `c` is valid as a first character of an identifier.
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/// See [Rust language reference](https://doc.rust-lang.org/reference/identifiers.html) for
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/// a formal definition of valid identifier name.
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pub fn is_id_start(c: char) -> bool {
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// This is XID_Start OR '_' (which formally is not a XID_Start).
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c == '_' || c == '-' || unicode_xid::UnicodeXID::is_xid_start(c)
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}
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/// True if `c` is valid as a non-first character of an identifier.
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/// See [Rust language reference](https://doc.rust-lang.org/reference/identifiers.html) for
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/// a formal definition of valid identifier name.
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pub fn is_id_continue(c: char) -> bool {
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unicode_xid::UnicodeXID::is_xid_continue(c) || c == '-'
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}
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/// The passed string is lexically an identifier.
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pub fn is_ident(string: &str) -> bool {
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let mut chars = string.chars();
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if let Some(start) = chars.next() {
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is_id_start(start) && chars.all(is_id_continue)
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} else {
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false
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}
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}
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pub fn is_digit(ch: char) -> bool {
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('0'..='9').contains(&ch)
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}
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pub fn is_bin_digit(ch: char) -> bool {
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ch == '0' || ch == '1'
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}
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#[expect(dead_code)]
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pub fn is_nonzero_digit(ch: char) -> bool {
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('1'..='9').contains(&ch)
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}
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pub fn is_oct_digit(ch: char) -> bool {
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('0'..='7').contains(&ch)
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}
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pub fn is_hex_digit(ch: char) -> bool {
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('0'..='9').contains(&ch) || ('a'..='f').contains(&ch) || ('A'..='F').contains(&ch)
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}
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}
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macro_rules! tokens {
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($vis:vis $ty_name:ident:
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{
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$($name2:ident),*
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},
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{
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$($name:ident => $lexeme:literal),*
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}) => {
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#[allow(dead_code)]
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#[derive(Debug, Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Hash)]
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$vis enum $ty_name {
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$($name,
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)*
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$($name2,)*
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}
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impl ::core::fmt::Display for $ty_name {
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fn fmt(&self, f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
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match self {
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$(Self::$name => write!(f, "{}", $lexeme),)*
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$(Self::$name2 => write!(f, "<{}>", stringify!($name2))),*
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}
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}
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}
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#[allow(dead_code)]
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impl $ty_name {
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$vis fn lexeme(&self) -> Option<&'static str> {
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match self {
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$(Self::$name => Some($lexeme),)*
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$(Self::$name2 => None),*
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}
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}
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/// returns the number of chars in this lexeme
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$vis fn lexeme_len(&self) -> usize {
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self.lexeme().map(|lexeme|lexeme.chars().count()).unwrap_or(0)
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}
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/// returns the number of chars in this lexeme
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$vis fn lexeme_len_utf8(&self) -> usize {
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self.lexeme().map(|lexeme|lexeme.len()).unwrap_or(0)
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}
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$vis fn maybe_ident(&self) -> bool {
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self.lexeme().map(|lexeme| crate::is_things::is_ident(lexeme)).unwrap_or(false)
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}
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$vis fn lexemes() -> &'static [(Self, &'static str)] {
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&[
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$((Self::$name, $lexeme)),*
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]
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}
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}
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};
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}
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tokens!(pub Token: {
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Eof,
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ParseError,
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// Marker Token for any Comment
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Comment,
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DocComment,
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// Marker Token for any pre-processing directive
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CharConstant,
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IntegerConstant,
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IntegerHexConstant,
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IntegerBinConstant,
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IntegerOctConstant,
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FloatingConstant,
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FloatingExpConstant,
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DotFloatingConstant,
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DotFloatingExpConstant,
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StringConstant,
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Ident
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},
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// Lexical Tokens:
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{
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SlashSlash => "//",
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SlashSlashSlash => "///",
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// SlashStar => "/*",
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// SlashStarStar => "/**",
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//StarSlash => "*/",
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// Punctuation:
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OpenParens => "(",
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CloseParens => ")",
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OpenBrace => "{",
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CloseBrace => "}",
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OpenSquareBracket => "[",
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CloseSquareBracket => "]",
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Semi => ";",
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Comma => ",",
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Elipsis3 => "...",
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Elipsis2 => "..",
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Colon => ":",
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Equal => "=",
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// Keywords:
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Void => "void",
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Bool => "bool",
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F32 => "f32",
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F64 => "f64",
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ISize => "isize",
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USize => "usize",
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U1 => "u1",
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U8 => "u8",
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U16 => "u16",
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U32 => "u32",
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U64 => "u64",
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I1 => "i1",
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I8 => "i8",
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I16 => "i16",
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I32 => "i32",
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I64 => "i64",
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Const => "const",
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Volatile => "volatile",
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Noalias => "noalias",
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Fn => "fn",
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Let => "let",
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Var => "var",
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If => "if",
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As => "as",
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Else => "else",
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Return => "return",
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Struct => "struct",
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Type => "type",
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Union => "union",
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Enum => "enum",
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Packed => "packed",
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Extern => "extern",
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Pub => "pub",
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// Operators
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Dot => ".",
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MinusGreater => "->",
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Bang => "!",
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Tilde => "~",
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Plus => "+",
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// PlusPlus => "++",
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Minus => "-",
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// MinusMinus => "--",
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Star => "*",
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Slash => "/",
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Percent => "%",
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Less => "<",
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Greater => ">",
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LessEqual => "<=",
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GreaterEqual => ">=",
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EqualEqual => "==",
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BangEqual => "!=",
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PipePipe => "||",
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AmpersandAmpersand => "&&",
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Ampersand => "&",
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Caret => "^",
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Pipe => "|",
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LessLess => "<<",
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GreaterGreater => ">>",
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Question => "?",
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PlusEqual => "+=",
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MinusEqual => "-=",
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StarEqual => "*=",
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SlashEqual => "/=",
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PercentEqual => "%=",
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AmpersandEqual => "&=",
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PipeEqual => "|=",
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CaretEqual => "^=",
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LessLessEqual => "<<=",
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GreaterGreaterEqual => ">>="
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});
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impl Token {
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pub fn is_assignment_op(self) -> bool {
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match self {
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Token::PlusEqual
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| Token::MinusEqual
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| Token::StarEqual
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| Token::SlashEqual
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| Token::PercentEqual
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| Token::PipeEqual
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| Token::CaretEqual
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| Token::AmpersandEqual
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| Token::LessLessEqual
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| Token::GreaterGreaterEqual
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| Token::Equal => true,
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_ => false,
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}
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}
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pub fn is_unary_op(self) -> bool {
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match self {
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Token::Plus | Token::Minus | Token::Star | Token::Ampersand | Token::Bang => true,
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_ => false,
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}
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}
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pub fn is_binary_op(self) -> bool {
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match self {
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Token::Star
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| Token::Slash
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| Token::Percent
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| Token::Pipe
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| Token::Ampersand
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| Token::Caret
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| Token::Plus
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| Token::Minus
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| Token::PipePipe
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| Token::AmpersandAmpersand
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| Token::BangEqual
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| Token::EqualEqual
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| Token::Less
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| Token::Greater
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| Token::LessEqual
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| Token::GreaterEqual
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| Token::LessLess
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| Token::GreaterGreater => true,
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_ => false,
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}
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}
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}
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use trie::Tree;
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#[derive(Debug, Clone, Copy)]
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struct CountingIterator<I: Iterator> {
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iter: I,
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count: usize,
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}
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impl<I: Iterator> From<I> for CountingIterator<I> {
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fn from(iter: I) -> Self {
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Self { iter, count: 0 }
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}
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}
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impl<I: Iterator<Item = char>> Iterator for CountingIterator<I> {
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type Item = I::Item;
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fn next(&mut self) -> Option<Self::Item> {
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self.iter.next().inspect(|c| self.count += c.len_utf8())
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}
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}
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impl<I: Iterator> CountingIterator<I> {
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pub(crate) fn offset(&self) -> usize {
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self.count
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}
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}
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impl<I: Iterator> core::ops::Deref for CountingIterator<I> {
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type Target = I;
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fn deref(&self) -> &Self::Target {
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&self.iter
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}
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}
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impl<I: Iterator> core::ops::DerefMut for CountingIterator<I> {
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fn deref_mut(&mut self) -> &mut Self::Target {
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&mut self.iter
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}
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}
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type Source<'a> = CountingIterator<core::iter::Peekable<core::str::Chars<'a>>>;
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pub struct TokenIterator<'a> {
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trie: Tree<char, Token>,
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source: &'a str,
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offset: usize,
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}
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impl<'a> TokenIterator<'a> {
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pub fn new(source: &'a str) -> Self {
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let mut trie = Tree::new();
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for (token, token_str) in Token::lexemes() {
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trie.insert(token_str.chars(), *token);
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}
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Self {
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trie,
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source,
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offset: 0,
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}
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}
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fn peekable_source(&self) -> Source<'a> {
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CountingIterator::from(self.source[self.offset..].chars().peekable())
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}
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fn parse(&mut self) -> Option<Token> {
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let mut iter = CountingIterator::from(self.source[self.offset..].chars());
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match self.trie.get_closest(&mut iter) {
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Some(token) => {
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// skip the peeked item
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self.offset += token.lexeme_len();
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Some(*token)
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}
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None => None,
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}
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}
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fn skip_whitespaces(&mut self) -> usize {
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self.skip_while(is_things::is_whitespace)
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}
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fn skip(&mut self, mut n: usize) -> usize {
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self.skip_while(|_| {
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n -= 1;
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n > 0
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})
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}
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fn skip_while(&mut self, mut pred: impl FnMut(char) -> bool) -> usize {
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let mut count = 0;
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loop {
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let Some(c) = self.source[self.offset..].chars().next() else {
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break;
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};
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if pred(c) {
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self.offset += c.len_utf8();
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count += c.len_utf8();
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continue;
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} else {
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break;
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}
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}
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count
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}
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}
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impl<'a> Iterator for TokenIterator<'a> {
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type Item = (Token, &'a str);
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fn next(&mut self) -> Option<Self::Item> {
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// skip whitespace
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self.skip_whitespaces();
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let start = self.offset;
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let mut source = self.peekable_source();
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let mut cursor = self.peekable_source();
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let token = match cursor.next() {
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Some('0'..='9') => {
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let token = complex_tokens::parse_constant(&mut source).ok()?;
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self.offset += source.offset();
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Some((token, &self.source[start..self.offset]))
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}
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Some('.') if cursor.next().map_or(false, is_things::is_digit) => {
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let token = complex_tokens::parse_constant(&mut source).ok()?;
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self.offset += source.offset();
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Some((token, &self.source[start..self.offset]))
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}
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Some('\'' | '"') => {
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let token = complex_tokens::parse_string_or_char_constant(&mut source).ok()?;
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self.offset += source.offset();
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Some((token, &self.source[start..self.offset]))
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}
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Some('`') => {
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// raw identifier
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self.skip(1);
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self.skip_while(|c| is_things::is_id_continue(c));
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if self.peekable_source().next() == Some('`') {
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self.skip(1);
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Some((Token::Ident, &self.source[start..self.offset]))
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} else {
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// unterminated raw identifier
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Some((Token::ParseError, &self.source[start..self.offset]))
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}
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}
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// `//`-style comments or doc-comments
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_ => match self.parse().map(|tok| match tok {
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Token::SlashSlash => {
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self.skip_while(|c| c == '\n');
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Token::Comment
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}
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Token::SlashSlashSlash => {
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self.skip_while(|c| c == '\n');
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Token::DocComment
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}
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_ => tok,
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}) {
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Some(tok) => {
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if tok.maybe_ident() && self.skip_while(|c| is_things::is_id_continue(c)) > 0 {
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Some((Token::Ident, &self.source[start..self.offset]))
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} else {
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Some((tok, &self.source[start..self.offset]))
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}
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}
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None => {
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if self
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.peekable_source()
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.next()
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.map_or(false, |c| is_things::is_id_start(c))
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{
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self.skip(1);
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self.skip_while(|c| is_things::is_id_continue(c));
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Some((Token::Ident, &self.source[start..self.offset]))
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} else {
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None
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}
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}
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},
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};
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token
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}
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}
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mod complex_tokens;
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_iterator() {
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let tokens = "fn let void+(+bool)";
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let mut lexer = TokenIterator::new(&tokens);
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assert_eq!(lexer.next(), Some((Token::Fn, "fn")));
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assert_eq!(lexer.next(), Some((Token::Let, "let")));
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assert_eq!(lexer.next(), Some((Token::Void, "void")));
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assert_eq!(lexer.next(), Some((Token::Plus, "+")));
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assert_eq!(lexer.next(), Some((Token::OpenParens, "(")));
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assert_eq!(lexer.next(), Some((Token::Plus, "+")));
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assert_eq!(lexer.next(), Some((Token::Bool, "bool")));
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assert_eq!(lexer.next(), Some((Token::CloseParens, ")")));
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assert_eq!(lexer.next(), None);
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}
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#[test]
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fn idents() {
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let lexer = TokenIterator::new("a a1 a_ a-b _a _1 _- -a -1 -_ `123");
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assert!(lexer.map(|(tok, _)| tok).all(|tok| tok == Token::Ident));
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}
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#[test]
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fn ident_minus_ambiguity() {
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let lexer = TokenIterator::new("a-a a- - a -a --a");
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let tokens = lexer.map(|(tok, _)| tok).collect::<Vec<_>>();
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assert_eq!(
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tokens,
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vec![
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Token::Ident,
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Token::Ident,
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Token::Minus,
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Token::Ident,
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Token::Ident,
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Token::Ident
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]
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);
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}
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#[test]
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fn complex_iterator() {
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let tokens = "fn my-function(x: i32, y: f32) -> f32 { return x + y; }";
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let mut lexer = TokenIterator::new(&tokens);
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assert_eq!(lexer.next(), Some((Token::Fn, "fn")));
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assert_eq!(lexer.next(), Some((Token::Ident, "my-function")));
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assert_eq!(lexer.next(), Some((Token::OpenParens, "(")));
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assert_eq!(lexer.next(), Some((Token::Ident, "x")));
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assert_eq!(lexer.next(), Some((Token::Colon, ":")));
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assert_eq!(lexer.next(), Some((Token::I32, "i32")));
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|
assert_eq!(lexer.next(), Some((Token::Comma, ",")));
|
|
assert_eq!(lexer.next(), Some((Token::Ident, "y")));
|
|
assert_eq!(lexer.next(), Some((Token::Colon, ":")));
|
|
assert_eq!(lexer.next(), Some((Token::F32, "f32")));
|
|
assert_eq!(lexer.next(), Some((Token::CloseParens, ")")));
|
|
assert_eq!(lexer.next(), Some((Token::MinusGreater, "->")));
|
|
assert_eq!(lexer.next(), Some((Token::F32, "f32")));
|
|
assert_eq!(lexer.next(), Some((Token::OpenBrace, "{")));
|
|
assert_eq!(lexer.next(), Some((Token::Return, "return")));
|
|
assert_eq!(lexer.next(), Some((Token::Ident, "x")));
|
|
assert_eq!(lexer.next(), Some((Token::Plus, "+")));
|
|
assert_eq!(lexer.next(), Some((Token::Ident, "y")));
|
|
assert_eq!(lexer.next(), Some((Token::Semi, ";")));
|
|
assert_eq!(lexer.next(), Some((Token::CloseBrace, "}")));
|
|
assert_eq!(lexer.next(), None);
|
|
}
|
|
}
|