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kill old lexer

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This commit is contained in:
Aleksey Kladov 2019-07-22 17:56:19 +03:00
parent 75761c0e47
commit 700669bbd0
6 changed files with 17 additions and 571 deletions
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165
crates/ra_syntax/src/parsing/lexer.rs
View File

@ -1,22 +1,6 @@
mod classes;
mod comments;
mod numbers;
mod ptr;
mod strings;
use crate::{
SyntaxKind::{self, *},
TextUnit, T,
};
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,
},
TextUnit,
};
/// A token of Rust source.
@ -141,138 +125,23 @@ pub fn tokenize(text: &str) -> Vec<Token> {
acc
}
/// Get the next token from a string
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.current(), ptr.nth(1));
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 {
// Possiblily multi-byte tokens,
// but we only produce single byte token now
// T![...], T![..], T![..=], T![.]
'.' => return T![.],
// T![::] T![:]
':' => return T![:],
// T![==] FATARROW T![=]
'=' => return T![=],
// T![!=] T![!]
'!' => return T![!],
// T![->] T![-]
'-' => return T![-],
// If the character is an ident start not followed by another single
// quote, then this is a lifetime name:
'\'' => {
return if ptr.at_p(is_ident_start) && !ptr.at_str("''") {
ptr.bump();
while ptr.at_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.at('\'') {
ptr.bump();
return CHAR;
}
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_raw = match (c, ptr.current()) {
('r', Some('#')) => {
ptr.bump();
true
}
('_', None) => return T![_],
('_', Some(c)) if !is_ident_continue(c) => return T![_],
_ => false,
};
ptr.bump_while(is_ident_continue);
if !is_raw {
if let Some(kind) = SyntaxKind::from_keyword(ptr.current_token_text()) {
return kind;
}
}
IDENT
}
fn scan_literal_suffix(ptr: &mut Ptr) {
if ptr.at_p(is_ident_start) {
ptr.bump();
}
ptr.bump_while(is_ident_continue);
}
pub fn classify_literal(text: &str) -> Option<Token> {
let tkn = next_token(text);
if !tkn.kind.is_literal() || tkn.len.to_usize() != text.len() {
let t = ra_rustc_lexer::first_token(text);
if t.len != text.len() {
return None;
}
Some(tkn)
let kind = match t.kind {
ra_rustc_lexer::TokenKind::Literal { kind, .. } => match kind {
ra_rustc_lexer::LiteralKind::Int { .. } => INT_NUMBER,
ra_rustc_lexer::LiteralKind::Float { .. } => FLOAT_NUMBER,
ra_rustc_lexer::LiteralKind::Char { .. } => CHAR,
ra_rustc_lexer::LiteralKind::Byte { .. } => BYTE,
ra_rustc_lexer::LiteralKind::Str { .. } => STRING,
ra_rustc_lexer::LiteralKind::ByteStr { .. } => BYTE_STRING,
ra_rustc_lexer::LiteralKind::RawStr { .. } => RAW_STRING,
ra_rustc_lexer::LiteralKind::RawByteStr { .. } => RAW_BYTE_STRING,
},
_ => return None,
};
Some(Token { kind, len: TextUnit::from_usize(t.len) })
}

26
crates/ra_syntax/src/parsing/lexer/classes.rs
View File

@ -1,26 +0,0 @@
use unicode_xid::UnicodeXID;
pub fn is_ident_start(c: char) -> bool {
(c >= 'a' && c <= 'z')
|| (c >= 'A' && c <= 'Z')
|| c == '_'
|| (c > '\x7f' && UnicodeXID::is_xid_start(c))
}
pub fn is_ident_continue(c: char) -> bool {
(c >= 'a' && c <= 'z')
|| (c >= 'A' && c <= 'Z')
|| (c >= '0' && c <= '9')
|| c == '_'
|| (c > '\x7f' && UnicodeXID::is_xid_continue(c))
}
pub fn is_whitespace(c: char) -> bool {
//FIXME: use is_pattern_whitespace
//https://github.com/behnam/rust-unic/issues/192
c.is_whitespace()
}
pub fn is_dec_digit(c: char) -> bool {
'0' <= c && c <= '9'
}

57
crates/ra_syntax/src/parsing/lexer/comments.rs
View File

@ -1,57 +0,0 @@
use crate::parsing::lexer::ptr::Ptr;
use crate::SyntaxKind::{self, *};
pub(crate) fn scan_shebang(ptr: &mut Ptr) -> bool {
if ptr.at_str("!/") {
ptr.bump();
ptr.bump();
bump_until_eol(ptr);
true
} else {
false
}
}
fn scan_block_comment(ptr: &mut Ptr) -> Option<SyntaxKind> {
if ptr.at('*') {
ptr.bump();
let mut depth: u32 = 1;
while depth > 0 {
if ptr.at_str("*/") {
depth -= 1;
ptr.bump();
ptr.bump();
} else if ptr.at_str("/*") {
depth += 1;
ptr.bump();
ptr.bump();
} else if ptr.bump().is_none() {
break;
}
}
Some(COMMENT)
} else {
None
}
}
pub(crate) fn scan_comment(ptr: &mut Ptr) -> Option<SyntaxKind> {
if ptr.at('/') {
bump_until_eol(ptr);
Some(COMMENT)
} else {
scan_block_comment(ptr)
}
}
fn bump_until_eol(ptr: &mut Ptr) {
loop {
if ptr.at('\n') || ptr.at_str("\r\n") {
return;
}
if ptr.bump().is_none() {
break;
}
}
}

66
crates/ra_syntax/src/parsing/lexer/numbers.rs
View File

@ -1,66 +0,0 @@
use crate::parsing::lexer::{classes::*, ptr::Ptr};
use crate::SyntaxKind::{self, *};
pub(crate) fn scan_number(c: char, ptr: &mut Ptr) -> SyntaxKind {
if c == '0' {
match ptr.current().unwrap_or('\0') {
'b' | 'o' => {
ptr.bump();
scan_digits(ptr, false);
}
'x' => {
ptr.bump();
scan_digits(ptr, true);
}
'0'..='9' | '_' | '.' | 'e' | 'E' => {
scan_digits(ptr, true);
}
_ => return INT_NUMBER,
}
} else {
scan_digits(ptr, false);
}
// might be a float, but don't be greedy if this is actually an
// integer literal followed by field/method access or a range pattern
// (`0..2` and `12.foo()`)
if ptr.at('.') && !(ptr.at_str("..") || ptr.nth_is_p(1, is_ident_start)) {
// might have stuff after the ., and if it does, it needs to start
// with a number
ptr.bump();
scan_digits(ptr, false);
scan_float_exponent(ptr);
return FLOAT_NUMBER;
}
// it might be a float if it has an exponent
if ptr.at('e') || ptr.at('E') {
scan_float_exponent(ptr);
return FLOAT_NUMBER;
}
INT_NUMBER
}
fn scan_digits(ptr: &mut Ptr, allow_hex: bool) {
while let Some(c) = ptr.current() {
match c {
'_' | '0'..='9' => {
ptr.bump();
}
'a'..='f' | 'A'..='F' if allow_hex => {
ptr.bump();
}
_ => return,
}
}
}
fn scan_float_exponent(ptr: &mut Ptr) {
if ptr.at('e') || ptr.at('E') {
ptr.bump();
if ptr.at('-') || ptr.at('+') {
ptr.bump();
}
scan_digits(ptr, false);
}
}

162
crates/ra_syntax/src/parsing/lexer/ptr.rs
View File

@ -1,162 +0,0 @@
use crate::TextUnit;
use std::str::Chars;
/// A simple view into the characters of a string.
pub(crate) struct Ptr<'s> {
text: &'s str,
len: TextUnit,
}
impl<'s> Ptr<'s> {
/// Creates a new `Ptr` from a string.
pub fn new(text: &'s str) -> Ptr<'s> {
Ptr { text, len: 0.into() }
}
/// Gets the length of the remaining string.
pub fn into_len(self) -> TextUnit {
self.len
}
/// Gets the current character, if one exists.
pub fn current(&self) -> Option<char> {
self.chars().next()
}
/// Gets the nth character from the current.
/// For example, 0 will return the current character, 1 will return the next, etc.
pub fn nth(&self, n: u32) -> Option<char> {
self.chars().nth(n as usize)
}
/// Checks whether the current character is `c`.
pub fn at(&self, c: char) -> bool {
self.current() == Some(c)
}
/// Checks whether the next characters match `s`.
pub fn at_str(&self, s: &str) -> bool {
let chars = self.chars();
chars.as_str().starts_with(s)
}
/// Checks whether the current character satisfies the predicate `p`.
pub fn at_p<P: Fn(char) -> bool>(&self, p: P) -> bool {
self.current().map(p) == Some(true)
}
/// Checks whether the nth character satisfies the predicate `p`.
pub fn nth_is_p<P: Fn(char) -> bool>(&self, n: u32, p: P) -> bool {
self.nth(n).map(p) == Some(true)
}
/// Moves to the next character.
pub fn bump(&mut self) -> Option<char> {
let ch = self.chars().next()?;
self.len += TextUnit::of_char(ch);
Some(ch)
}
/// Moves to the next character as long as `pred` is satisfied.
pub fn bump_while<F: Fn(char) -> bool>(&mut self, pred: F) {
loop {
match self.current() {
Some(c) if pred(c) => {
self.bump();
}
_ => return,
}
}
}
/// Returns the text up to the current point.
pub fn current_token_text(&self) -> &str {
let len: u32 = self.len.into();
&self.text[..len as usize]
}
/// Returns an iterator over the remaining characters.
fn chars(&self) -> Chars {
let len: u32 = self.len.into();
self.text[len as usize..].chars()
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_current() {
let ptr = Ptr::new("test");
assert_eq!(ptr.current(), Some('t'));
}
#[test]
fn test_nth() {
let ptr = Ptr::new("test");
assert_eq!(ptr.nth(0), Some('t'));
assert_eq!(ptr.nth(1), Some('e'));
assert_eq!(ptr.nth(2), Some('s'));
assert_eq!(ptr.nth(3), Some('t'));
assert_eq!(ptr.nth(4), None);
}
#[test]
fn test_at() {
let ptr = Ptr::new("test");
assert!(ptr.at('t'));
assert!(!ptr.at('a'));
}
#[test]
fn test_at_str() {
let ptr = Ptr::new("test");
assert!(ptr.at_str("t"));
assert!(ptr.at_str("te"));
assert!(ptr.at_str("test"));
assert!(!ptr.at_str("tests"));
assert!(!ptr.at_str("rust"));
}
#[test]
fn test_at_p() {
let ptr = Ptr::new("test");
assert!(ptr.at_p(|c| c == 't'));
assert!(!ptr.at_p(|c| c == 'e'));
}
#[test]
fn test_nth_is_p() {
let ptr = Ptr::new("test");
assert!(ptr.nth_is_p(0, |c| c == 't'));
assert!(!ptr.nth_is_p(1, |c| c == 't'));
assert!(ptr.nth_is_p(3, |c| c == 't'));
assert!(!ptr.nth_is_p(150, |c| c == 't'));
}
#[test]
fn test_bump() {
let mut ptr = Ptr::new("test");
assert_eq!(ptr.current(), Some('t'));
ptr.bump();
assert_eq!(ptr.current(), Some('e'));
ptr.bump();
assert_eq!(ptr.current(), Some('s'));
ptr.bump();
assert_eq!(ptr.current(), Some('t'));
ptr.bump();
assert_eq!(ptr.current(), None);
ptr.bump();
assert_eq!(ptr.current(), None);
}
#[test]
fn test_bump_while() {
let mut ptr = Ptr::new("test");
assert_eq!(ptr.current(), Some('t'));
ptr.bump_while(|c| c != 's');
assert_eq!(ptr.current(), Some('s'));
}
}

112
crates/ra_syntax/src/parsing/lexer/strings.rs
View File

@ -1,112 +0,0 @@
use crate::{
parsing::lexer::ptr::Ptr,
SyntaxKind::{self, *},
};
pub(crate) fn is_string_literal_start(c: char, c1: Option<char>, c2: Option<char>) -> bool {
match (c, c1, c2) {
('r', Some('"'), _)
| ('r', Some('#'), Some('"'))
| ('r', Some('#'), Some('#'))
| ('b', Some('"'), _)
| ('b', Some('\''), _)
| ('b', Some('r'), Some('"'))
| ('b', Some('r'), Some('#')) => true,
_ => false,
}
}
pub(crate) fn scan_char(ptr: &mut Ptr) {
while let Some(c) = ptr.current() {
match c {
'\\' => {
ptr.bump();
if ptr.at('\\') || ptr.at('\'') {
ptr.bump();
}
}
'\'' => {
ptr.bump();
return;
}
'\n' => return,
_ => {
ptr.bump();
}
}
}
}
pub(crate) fn scan_byte_char_or_string(ptr: &mut Ptr) -> SyntaxKind {
// unwrapping and not-exhaustive match are ok
// because of string_literal_start
let c = ptr.bump().unwrap();
match c {
'\'' => {
scan_byte(ptr);
BYTE
}
'"' => {
scan_byte_string(ptr);
BYTE_STRING
}
'r' => {
scan_raw_string(ptr);
RAW_BYTE_STRING
}
_ => unreachable!(),
}
}
pub(crate) fn scan_string(ptr: &mut Ptr) {
while let Some(c) = ptr.current() {
match c {
'\\' => {
ptr.bump();
if ptr.at('\\') || ptr.at('"') {
ptr.bump();
}
}
'"' => {
ptr.bump();
return;
}
_ => {
ptr.bump();
}
}
}
}
pub(crate) fn scan_raw_string(ptr: &mut Ptr) {
let mut hashes = 0;
while ptr.at('#') {
hashes += 1;
ptr.bump();
}
if !ptr.at('"') {
return;
}
ptr.bump();
while let Some(c) = ptr.bump() {
if c == '"' {
let mut hashes_left = hashes;
while ptr.at('#') && hashes_left > 0 {
hashes_left -= 1;
ptr.bump();
}
if hashes_left == 0 {
return;
}
}
}
}
fn scan_byte(ptr: &mut Ptr) {
scan_char(ptr)
}
fn scan_byte_string(ptr: &mut Ptr) {
scan_string(ptr)
}