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Clarify StringReader::bump.

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This commit renames the variables to make it clearer which char each one
refers to. It also slightly reorders and rearranges some statements.
This commit is contained in:
Nicholas Nethercote 2016-10-04 12:04:19 +11:00
parent e2631208b1
commit 94b36594c6
1 changed files with 16 additions and 13 deletions
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29
src/libsyntax/parse/lexer/mod.rs
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@ -414,27 +414,30 @@ impl<'a> StringReader<'a> {
/// Advance the StringReader by one character. If a newline is
/// discovered, add it to the FileMap's list of line start offsets.
pub fn bump(&mut self) {
self.pos = self.next_pos;
let current_byte_offset = self.byte_offset(self.next_pos).to_usize();
if current_byte_offset < self.source_text.len() {
let last_char = self.ch.unwrap();
let ch = char_at(&self.source_text, current_byte_offset);
let byte_offset_diff = ch.len_utf8();
self.next_pos = self.next_pos + Pos::from_usize(byte_offset_diff);
self.ch = Some(ch);
self.col = self.col + CharPos(1);
if last_char == '\n' {
let new_pos = self.next_pos;
let new_byte_offset = self.byte_offset(new_pos).to_usize();
if new_byte_offset < self.source_text.len() {
let old_ch_is_newline = self.ch.unwrap() == '\n';
let new_ch = char_at(&self.source_text, new_byte_offset);
let new_ch_len = new_ch.len_utf8();
self.ch = Some(new_ch);
self.pos = new_pos;
self.next_pos = new_pos + Pos::from_usize(new_ch_len);
if old_ch_is_newline {
if self.save_new_lines {
self.filemap.next_line(self.pos);
}
self.col = CharPos(0);
} else {
self.col = self.col + CharPos(1);
}
if byte_offset_diff > 1 {
self.filemap.record_multibyte_char(self.pos, byte_offset_diff);
if new_ch_len > 1 {
self.filemap.record_multibyte_char(self.pos, new_ch_len);
}
} else {
self.ch = None;
self.pos = new_pos;
}
}