message: Clean up blend.rs, make it more easy-to-read
diff: @@ -30,24 +30,24 @@ impl<'a> Blend<'a> {
  }
  fn blend(&self, columns: &Vec<Column>, row: Row) -> Result<Row> {
  - let Row(items) = row;
  - let items = items
  + let Row(values) = row;
  + let values = values
  .into_iter()
  - .enumerate()
  - .filter_map(|(i, v)| self.check(&columns, v, i))
  + .zip(columns.iter())
  + .filter_map(|(value, column)| self.find(value, column))
  .collect::<Result<_>>()?;
  - Ok(Row(items))
  + Ok(Row(values))
  }
  - fn check(&self, columns: &Vec<Column>, value: Value, index: usize) -> Option<Result<Value>> {
  + fn find(&self, value: Value, target: &Column) -> Option<Result<Value>> {
  for expr in self.fields {
  match expr {
  FieldDefinitionExpression::All => {
  return Some(Ok(value));
  }
  FieldDefinitionExpression::Col(column) => {
  - if column.name == columns[index].name {
  + if column.name == target.name {
  return Some(Ok(value));
  }
  }
  