Crate sval_flatten

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Expand description

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