68 lines
1.7 KiB
Rust
68 lines
1.7 KiB
Rust
use std::{iter::Peekable, str::Chars};
|
|
|
|
use super::super::{CompilerMsg, FilePos};
|
|
|
|
pub struct CharCursor<'a> {
|
|
chars: Peekable<Chars<'a>>,
|
|
next_pos: FilePos,
|
|
prev_pos: FilePos,
|
|
}
|
|
|
|
impl CharCursor<'_> {
|
|
pub fn next(&mut self) -> Option<char> {
|
|
let res = self.peek()?;
|
|
self.advance();
|
|
Some(res)
|
|
}
|
|
pub fn expect(&mut self, c: char) -> Result<(), CompilerMsg> {
|
|
let next = self.expect_next()?;
|
|
if next == c {
|
|
Ok(())
|
|
} else {
|
|
Err(CompilerMsg::at(
|
|
self.prev_pos,
|
|
format!("unexpected char '{next}'; expected '{c}'"),
|
|
))
|
|
}
|
|
}
|
|
pub fn skip_whitespace(&mut self) {
|
|
while self.peek().is_some_and(|c| c.is_whitespace()) {
|
|
self.advance();
|
|
}
|
|
}
|
|
pub fn peek(&mut self) -> Option<char> {
|
|
self.chars.peek().copied()
|
|
}
|
|
pub fn advance(&mut self) {
|
|
let Some(next) = self.chars.next() else {
|
|
return;
|
|
};
|
|
self.prev_pos = self.next_pos;
|
|
if next == '\n' {
|
|
self.next_pos.col = 0;
|
|
self.next_pos.line += 1;
|
|
} else {
|
|
self.next_pos.col += 1;
|
|
}
|
|
}
|
|
pub fn expect_next(&mut self) -> Result<char, CompilerMsg> {
|
|
self.next().ok_or(CompilerMsg::unexpected_end())
|
|
}
|
|
pub fn next_pos(&self) -> FilePos {
|
|
self.next_pos
|
|
}
|
|
pub fn prev_pos(&self) -> FilePos {
|
|
self.prev_pos
|
|
}
|
|
}
|
|
|
|
impl<'a> From<&'a str> for CharCursor<'a> {
|
|
fn from(value: &'a str) -> Self {
|
|
Self {
|
|
chars: value.chars().peekable(),
|
|
next_pos: FilePos::start(),
|
|
prev_pos: FilePos::start(),
|
|
}
|
|
}
|
|
}
|