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|
mod classes;
mod comments;
mod numbers;
mod ptr;
mod strings;
use {
SyntaxKind::{self, *},
TextUnit,
};
use self::{
classes::*,
comments::{scan_comment, scan_shebang},
numbers::scan_number,
ptr::Ptr,
strings::{
is_string_literal_start, scan_byte_char_or_string, scan_char, scan_raw_string, scan_string,
},
};
/// A token of Rust source.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Token {
/// The kind of token.
pub kind: SyntaxKind,
/// The length of the token.
pub len: TextUnit,
}
/// Break a string up into its component tokens
pub fn tokenize(text: &str) -> Vec<Token> {
let mut text = text;
let mut acc = Vec::new();
while !text.is_empty() {
let token = next_token(text);
acc.push(token);
let len: u32 = token.len.into();
text = &text[len as usize..];
}
acc
}
/// Get the next token from a 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 {
if is_whitespace(c) {
ptr.bump_while(is_whitespace);
return WHITESPACE;
}
match c {
'#' => if scan_shebang(ptr) {
return SHEBANG;
},
'/' => if let Some(kind) = scan_comment(ptr) {
return kind;
},
_ => (),
}
let ident_start = is_ident_start(c) && !is_string_literal_start(c, ptr.next(), ptr.nnext());
if ident_start {
return scan_ident(c, ptr);
}
if is_dec_digit(c) {
let kind = scan_number(c, ptr);
scan_literal_suffix(ptr);
return kind;
}
// One-byte tokens.
if let Some(kind) = SyntaxKind::from_char(c) {
return kind;
}
match c {
// 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
}
_ => EXCL,
};
}
'-' => {
return if ptr.next_is('>') {
ptr.bump();
THIN_ARROW
} else {
MINUS
};
}
// 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;
}
'"' => {
scan_string(ptr);
scan_literal_suffix(ptr);
return STRING;
}
'r' => {
scan_raw_string(ptr);
scan_literal_suffix(ptr);
return RAW_STRING;
}
_ => (),
}
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);
if let Some(kind) = SyntaxKind::from_keyword(ptr.current_token_text()) {
return kind;
}
IDENT
}
fn scan_literal_suffix(ptr: &mut Ptr) {
if ptr.next_is_p(is_ident_start) {
ptr.bump();
}
ptr.bump_while(is_ident_continue);
}
|
