format/substrait/extension_types.yaml

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# substrait::{ExtensionTypeVariation, ExtensionType}s
# for wrapping types which appear in the arrow type system but
# are not first-class in substrait. These include:
# - null
# - unsigned integers
# - half-precision floating point numbers
# - 32-bit times and 64-bit dates
# - timestamps with units other than microseconds
# - timestamps with timezones other than UTC
# - 256-bit decimals
# - sparse and dense unions
# - dictionary encoded types
# - durations
# - string and binary with 64 bit offsets
# - list with 64-bit offsets
# - interval<months: i32>
# - interval<days: i32, millis: i32>
# - interval<months: i32, days: i32, nanos: i64>
# - arrow::ExtensionTypes
#
# Note that not all of these are currently implemented. In particular, these
# extension types are currently not parameterizable in Substrait, which means
# among other things that we can't declare dictionary type here at all since
# we'd have to declare a different dictionary type for all encoded types
# (but that is an infinite space). Similarly, we would have to declare a
# timestamp variation for all possible timezone strings.

type_variations:
  - parent: i8
    name: u8
    description: an unsigned 8 bit integer
    functions: SEPARATE
  - parent: i16
    name: u16
    description: an unsigned 16 bit integer
    functions: SEPARATE
  - parent: i32
    name: u32
    description: an unsigned 32 bit integer
    functions: SEPARATE
  - parent: i64
    name: u64
    description: an unsigned 64 bit integer
    functions: SEPARATE

  - parent: i16
    name: fp16
    description: a 16 bit floating point number
    functions: SEPARATE

types:
  - name: "null"
    structure: {}
  - name: interval_month
    structure:
      months: i32
  - name: interval_day_milli
    structure:
      days: i32
      millis: i32
  - name: interval_month_day_nano
    structure:
      months: i32
      days: i32
      nanos: i64