Crate sval_flatten

Flatten nested values when streaming.

This library is like the standard library’s Iterator::flatten method, but for sval::Streams. Given a value, it will flatten its nested values onto a parent structure. It supports flattening any combination of map, sequence, record, or tuple onto any other.

If you’re using sval_derive, you can use the #[flatten] attribute on a field.

Specifics

Flattening unwraps containers and translates their values into the form needed by their parent. The following types can be flattened:

• maps
• sequences
• records
• tuples

Any other type, including primitives like tags, booleans, and text will be ignored if flattened.

Maps

• maps: keys are passed through directly, even if they’re complex values like other maps.
• sequences: keys are the stringified offset of sequence values.
• records: keys are the label of record values.
• tuples: keys are the stringified index of tuple values.

Sequences

• maps: map keys are ignored; only map values are flattened.
• sequences: sequence values are passed through directly.
• records: record values are passed through directly.
• tuples: tuple values are passed through directly.

Records

• maps: map keys are stringified into labels. For complex values like other maps each nested value is stringified and concatenated together.
• sequences: labels are the stringified offset of sequence values.
• records: labels are passed through directly.
• tuples: labels are the stringified index of tuple values.

Tuples

• maps: map keys are ignored; only map values are flattened.
• sequences: indexes are the offset of sequence values.
• records: indexes are the offset of record values.
• tuples: tuple values are passed through directly.

Functions

• flatten_to_map
  Flatten the fields of a value onto a map.
• flatten_to_record
  Flatten the fields of a value onto a record.
• flatten_to_record_tuple
  Flatten the fields of a value onto a record or tuple.
• flatten_to_seq
  Flatten the fields of a value onto a sequence.
• flatten_to_tuple
  Flatten the fields of a value onto a tuple.