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use super::Lexer;
use super::token::{Span, SpannedToken, Token};
use crate::error;
impl Lexer {
pub(crate) fn at_end(&self) -> bool {
self.pos >= self.input.len()
}
pub(crate) fn current_byte(&self) -> u8 {
if self.at_end() {
0
} else {
self.input[self.pos]
}
}
pub(crate) fn peek_byte(&self) -> u8 {
if self.pos + 1 >= self.input.len() {
0
} else {
self.input[self.pos + 1]
}
}
pub(crate) fn advance(&mut self) -> u8 {
let ch = self.current_byte();
if !self.at_end() {
if ch == b'\n' {
self.line += 1;
self.column = 1;
} else {
self.column += 1;
}
self.pos += 1;
}
ch
}
pub(crate) fn current_span(&self) -> Span {
Span {
line: self.line,
column: self.column,
}
}
pub(crate) fn skip_whitespace_and_comments(&mut self) {
loop {
match self.current_byte() {
b' ' | b'\t' => {
self.advance();
}
b'#' => {
// skip until newline (but don't consume the newline)
while !self.at_end() && self.current_byte() != b'\n' {
self.advance();
}
}
_ => break,
}
}
}
pub(crate) fn next_token_raw(&mut self) -> error::Result<SpannedToken> {
self.skip_whitespace_and_comments();
if self.at_end() {
let span = self.current_span();
return Ok(SpannedToken {
token: Token::Eof,
span,
});
}
let span = self.current_span();
match self.current_byte() {
b'\n' => {
self.advance();
Ok(SpannedToken {
token: Token::Newline,
span,
})
}
b'|' => self.read_pipe(),
b'&' => self.read_amp(),
b';' => self.read_semi(),
b'(' => {
let span = self.current_span();
self.advance();
Ok(SpannedToken {
token: Token::LParen,
span,
})
}
b')' => {
let span = self.current_span();
self.advance();
Ok(SpannedToken {
token: Token::RParen,
span,
})
}
b'<' => self.read_less(),
b'>' => self.read_great(),
ch => {
if ch.is_ascii_digit()
&& let Some(io_num) = self.try_read_io_number()
{
return Ok(SpannedToken {
token: io_num,
span,
});
}
self.read_word()
}
}
}
pub(crate) fn read_pipe(&mut self) -> error::Result<SpannedToken> {
let span = self.current_span();
self.advance(); // consume '|'
if self.current_byte() == b'|' {
self.advance();
Ok(SpannedToken {
token: Token::OrIf,
span,
})
} else {
Ok(SpannedToken {
token: Token::Pipe,
span,
})
}
}
pub(crate) fn read_amp(&mut self) -> error::Result<SpannedToken> {
let span = self.current_span();
self.advance(); // consume '&'
if self.current_byte() == b'&' {
self.advance();
Ok(SpannedToken {
token: Token::AndIf,
span,
})
} else {
Ok(SpannedToken {
token: Token::Amp,
span,
})
}
}
pub(crate) fn read_semi(&mut self) -> error::Result<SpannedToken> {
let span = self.current_span();
self.advance(); // consume ';'
match self.current_byte() {
b';' => {
self.advance();
Ok(SpannedToken {
token: Token::DSemi,
span,
})
}
b'&' => {
self.advance();
Ok(SpannedToken {
token: Token::SemiAnd,
span,
})
}
_ => Ok(SpannedToken {
token: Token::Semi,
span,
}),
}
}
pub(crate) fn read_less(&mut self) -> error::Result<SpannedToken> {
let span = self.current_span();
self.advance(); // consume '<'
match self.current_byte() {
b'<' => {
self.advance();
if self.current_byte() == b'-' {
self.advance();
Ok(SpannedToken {
token: Token::DLessDash,
span,
})
} else {
Ok(SpannedToken {
token: Token::DLess,
span,
})
}
}
b'&' => {
self.advance();
Ok(SpannedToken {
token: Token::LessAnd,
span,
})
}
b'>' => {
self.advance();
Ok(SpannedToken {
token: Token::LessGreat,
span,
})
}
_ => Ok(SpannedToken {
token: Token::Less,
span,
}),
}
}
pub(crate) fn read_great(&mut self) -> error::Result<SpannedToken> {
let span = self.current_span();
self.advance(); // consume '>'
match self.current_byte() {
b'>' => {
self.advance();
Ok(SpannedToken {
token: Token::DGreat,
span,
})
}
b'&' => {
self.advance();
Ok(SpannedToken {
token: Token::GreatAnd,
span,
})
}
b'|' => {
self.advance();
Ok(SpannedToken {
token: Token::Clobber,
span,
})
}
_ => Ok(SpannedToken {
token: Token::Great,
span,
}),
}
}
pub(crate) fn is_meta_or_whitespace(ch: u8) -> bool {
matches!(
ch,
b'|' | b'&' | b';' | b'(' | b')' | b'<' | b'>' | b' ' | b'\t' | b'\n'
)
}
/// Tries to read an IO_NUMBER token (digits immediately followed by `<` or `>`).
/// Returns None and restores state if not followed by a redirect operator.
pub(crate) fn try_read_io_number(&mut self) -> Option<Token> {
let state = self.save_state();
let mut digits = String::new();
while !self.at_end() && self.current_byte().is_ascii_digit() {
digits.push(self.current_byte() as char);
self.advance();
}
let next = self.current_byte();
if (next == b'<' || next == b'>')
&& let Ok(n) = digits.parse::<i32>()
{
return Some(Token::IoNumber(n));
}
// Not an IO_NUMBER: restore state
self.restore_state(state);
None
}
}