Clearer order of comparisons

We look at seq.first/map.first only once.
serde-rs · Oct 19, 2024 · f2082d2 · f2082d2
1 parent 0f54a1a
commit f2082d2
Showing 1 changed file with 30 additions and 38 deletions.
diff --git a/src/de.rs b/src/de.rs
@@ -1936,24 +1936,20 @@ impl<'de, 'a, R: Read<'de> + 'a> de::SeqAccess<'de> for SeqAccess<'a, R> {
  }
  };
 
- match peek {
- b']' => Ok(false),
- b',' if !seq.first => {
- seq.de.eat_char();
- match tri!(seq.de.parse_whitespace()) {
- Some(b']') => Err(seq.de.peek_error(ErrorCode::TrailingComma)),
- Some(_) => Ok(true),
- None => Err(seq.de.peek_error(ErrorCode::EofWhileParsingValue)),
- }
- }
- _ => {
- if seq.first {
- seq.first = false;
- Ok(true)
- } else {
- Err(seq.de.peek_error(ErrorCode::ExpectedListCommaOrEnd))
- }
+ if peek == b']' {
+ Ok(false)
+ } else if seq.first {
+ seq.first = false;
+ Ok(true)
+ } else if peek == b',' {
+ seq.de.eat_char();
+ match tri!(seq.de.parse_whitespace()) {
+ Some(b']') => Err(seq.de.peek_error(ErrorCode::TrailingComma)),
+ Some(_) => Ok(true),
+ None => Err(seq.de.peek_error(ErrorCode::EofWhileParsingValue)),
  }
+ } else {
+ Err(seq.de.peek_error(ErrorCode::ExpectedListCommaOrEnd))
  }
  }
 
@@ -1991,29 +1987,25 @@ impl<'de, 'a, R: Read<'de> + 'a> de::MapAccess<'de> for MapAccess<'a, R> {
  }
  };
 
- match peek {
- b'}' => Ok(false),
- b',' if !map.first => {
- map.de.eat_char();
- match tri!(map.de.parse_whitespace()) {
- Some(b'"') => Ok(true),
- Some(b'}') => Err(map.de.peek_error(ErrorCode::TrailingComma)),
- Some(_) => Err(map.de.peek_error(ErrorCode::KeyMustBeAString)),
- None => Err(map.de.peek_error(ErrorCode::EofWhileParsingValue)),
- }
+ if peek == b'}' {
+ Ok(false)
+ } else if map.first {
+ map.first = false;
+ if peek == b'"' {
+ Ok(true)
+ } else {
+ Err(map.de.peek_error(ErrorCode::KeyMustBeAString))
  }
- _ => {
- if map.first {
- map.first = false;
- if peek == b'"' {
- Ok(true)
- } else {
- Err(map.de.peek_error(ErrorCode::KeyMustBeAString))
- }
- } else {
- Err(map.de.peek_error(ErrorCode::ExpectedObjectCommaOrEnd))
- }
+ } else if peek == b',' {
+ map.de.eat_char();
+ match tri!(map.de.parse_whitespace()) {
+ Some(b'"') => Ok(true),
+ Some(b'}') => Err(map.de.peek_error(ErrorCode::TrailingComma)),
+ Some(_) => Err(map.de.peek_error(ErrorCode::KeyMustBeAString)),
+ None => Err(map.de.peek_error(ErrorCode::EofWhileParsingValue)),
  }
+ } else {
+ Err(map.de.peek_error(ErrorCode::ExpectedObjectCommaOrEnd))
  }
  }