use {Token, SyntaxKind}; use syntax_kinds::*; mod ptr; use self::ptr::Ptr; mod classes; use self::classes::*; mod numbers; use self::numbers::scan_number; mod strings; use self::strings::{string_literal_start, scan_char, scan_byte_char_or_string}; pub fn next_token(text: &str) -> Token { assert!(!text.is_empty()); let mut ptr = Ptr::new(text); let c = ptr.bump().unwrap(); let kind = next_token_inner(c, &mut ptr); let len = ptr.into_len(); Token { kind, len } } fn next_token_inner(c: char, ptr: &mut Ptr) -> SyntaxKind { // Note: r as in r" or r#" is part of a raw string literal, // b as in b' is part of a byte literal. // They are not identifiers, and are handled further down. let ident_start = is_ident_start(c) && !string_literal_start(c, ptr.next(), ptr.nnext()); if ident_start { return scan_ident(c, ptr); } if is_whitespace(c) { ptr.bump_while(is_whitespace); return WHITESPACE; } if is_dec_digit(c) { let kind = scan_number(c, ptr); scan_literal_suffix(ptr); return kind; } // One-byte tokens. match c { ';' => return SEMI, ',' => return COMMA, '(' => return L_PAREN, ')' => return R_PAREN, '{' => return L_CURLY, '}' => return R_CURLY, '[' => return L_BRACK, ']' => return R_BRACK, '<' => return L_ANGLE, '>' => return R_ANGLE, '@' => return AT, '#' => return POUND, '~' => return TILDE, '?' => return QUESTION, '$' => return DOLLAR, // Multi-byte tokens. '.' => return match (ptr.next(), ptr.nnext()) { (Some('.'), Some('.')) => { ptr.bump(); ptr.bump(); DOTDOTDOT }, (Some('.'), Some('=')) => { ptr.bump(); ptr.bump(); DOTDOTEQ }, (Some('.'), _) => { ptr.bump(); DOTDOT }, _ => DOT }, ':' => return match ptr.next() { Some(':') => { ptr.bump(); COLONCOLON } _ => COLON }, '=' => return match ptr.next() { Some('=') => { ptr.bump(); EQEQ } Some('>') => { ptr.bump(); FAT_ARROW } _ => EQ, }, '!' => return match ptr.next() { Some('=') => { ptr.bump(); NEQ } _ => NOT, }, // If the character is an ident start not followed by another single // quote, then this is a lifetime name: '\'' => return if ptr.next_is_p(is_ident_start) && !ptr.nnext_is('\'') { ptr.bump(); while ptr.next_is_p(is_ident_continue) { ptr.bump(); } // lifetimes shouldn't end with a single quote // if we find one, then this is an invalid character literal if ptr.next_is('\'') { ptr.bump(); return CHAR; // TODO: error reporting } LIFETIME } else { scan_char(ptr); scan_literal_suffix(ptr); CHAR }, 'b' => { let kind = scan_byte_char_or_string(ptr); scan_literal_suffix(ptr); return kind }, _ => (), } ERROR } fn scan_ident(c: char, ptr: &mut Ptr) -> SyntaxKind { let is_single_letter = match ptr.next() { None => true, Some(c) if !is_ident_continue(c) => true, _ => false, }; if is_single_letter { return if c == '_' { UNDERSCORE } else { IDENT }; } ptr.bump_while(is_ident_continue); IDENT } fn scan_literal_suffix(ptr: &mut Ptr) { if ptr.next_is_p(is_ident_start) { ptr.bump(); } ptr.bump_while(is_ident_continue); }