`avro.schema`

Avro schema parsing and printing.

The parsed schema is an arena of SchemaNodes with integer child indices. That is not just a Mojo workaround for self-referential structs: it is also exactly what Avro's named type references want — a record that refers to itself ({"type": "record", "name": "Node", "fields": [{"name": "next", "type": ["null", "Node"]}]}) is one node index appearing twice.

Everything the JSON carried that Avro does not define is preserved as a raw property (field-id, element-id, key-id, value-id — Apache Iceberg writes all four), so to_json() round-trips and consumers can read them back.

Structs

`Props`

struct Props

Ordered extra JSON attributes; values are kept as raw JSON text.

Implements Copyable, Defaultable, Movable, Sized

Fields: keys: List[String]; vals: List[String]

`init`

def __init__(out self)

`len`

def __len__(self) -> Int

`set`

def set(mut self, var key: String, var raw_json: String)

`get`

def get(self, key: StringSpan) -> String

Raw JSON text for key, or "" when absent.

`has`

def has(self, key: StringSpan) -> Bool

`get_int`

def get_int(self, key: StringSpan, default: Int = Int(-1)) -> Int

Integer property value, or default when absent or not a number.

`Field`

struct Field

One record field.

Implements Copyable, Movable

Fields: name: String; doc: String; type_index: Int: Index of the field's type node in the owning Schema's arena.; has_default: Bool; default_json: String: Raw JSON text of the field's default, when it has one.; order: String; aliases: List[String]; props: Props

`make`

def make(var name: String, type_index: Int) -> Self

`field_id`

def field_id(self) -> Int

Iceberg's field-id attribute, or -1 when the field has none.

`SchemaNode`

struct SchemaNode

Implements Copyable, Movable

Fields: kind: Int; name: String: Fullname (namespace-qualified) for record/enum/fixed; "" otherwise.; namespace: String; doc: String; aliases: List[String]; logical_type: String; precision: Int; scale: Int; size: Int: Byte width for fixed.; symbols: List[String]; default_symbol: String; fields: List[Field]; children: List[Int]: Array items / map values (one entry), or union branches.; props: Props

`of`

def of(kind: Int) -> Self

`short_name`

def short_name(self) -> String

`Schema`

struct Schema

A parsed Avro schema: an arena of nodes plus the root node's index.

Implements Copyable, Movable, Writable

Fields: nodes: List[SchemaNode]; root: Int; names: Dict[String, Int]: Fullname -> node index, for every named type the schema defines.

`init`

def __init__(out self)

`kind`

def kind(self, i: Int) -> Int

`root_kind`

def root_kind(self) -> Int

`name`

def name(self, i: Int) -> String

`logical_type`

def logical_type(self, i: Int) -> String

`size`

def size(self, i: Int) -> Int

`symbols`

def symbols(self, i: Int) -> List[String]

`num_fields`

def num_fields(self, i: Int) -> Int

`field`

def field(self, i: Int, k: Int) -> Field

`field_index`

def field_index(self, i: Int, name: StringSpan) -> Int

Position of the named field in record node i, or -1.

`field_type`

def field_type(self, i: Int, k: Int) -> Int

`items`

def items(self, i: Int) -> Int

Element node index of an array.

`values`

def values(self, i: Int) -> Int

Value node index of a map.

`num_branches`

def num_branches(self, i: Int) -> Int

`branch`

def branch(self, i: Int, k: Int) -> Int

`props`

def props(self, i: Int) -> Props

`is_optional`

def is_optional(self, i: Int) -> Bool

True for a two-branch union with a null branch — Iceberg's spelling of an optional field.

`optional_branch`

def optional_branch(self, i: Int) -> Int

For an optional union, the node index of the non-null branch; -1 otherwise.

`null_branch_index`

def null_branch_index(self, i: Int) -> Int

Branch position of the null member of a union, or -1.

`is_logical_map`

def is_logical_map(self, i: Int) -> Bool

An array of two-field records tagged "logicalType": "map" — how Avro (and Iceberg) spells a map with non-string keys.

`element_id`

def element_id(self, i: Int) -> Int

`key_id`

def key_id(self, i: Int) -> Int

`value_id`

def value_id(self, i: Int) -> Int

`to_json`

def to_json(self) -> String

`to_json_at`

def to_json_at(self, i: Int) -> String

`write_to`

def write_to(self, mut writer: T)

`parsing_canonical_form`

def parsing_canonical_form(self) -> String

`fingerprint`

def fingerprint(self) -> UInt64

The 64-bit Rabin fingerprint (CRC-64-AVRO) of the parsing canonical form — Avro's own single-object-encoding schema id.

Functions

`kind_name`

def kind_name(kind: Int) -> String

`primitive_kind`

def primitive_kind(name: StringSpan) -> Int

Kind for a primitive type name, or -1 if name is not primitive.

`is_primitive`

def is_primitive(kind: Int) -> Bool

`is_named`

def is_named(kind: Int) -> Bool

`crc64_avro`

def crc64_avro(data: Span[UInt8]) -> UInt64

Avro's CRC-64-AVRO Rabin fingerprint.

`parse_schema`

def parse_schema(text: StringSpan) -> Schema

Parse an Avro schema from its JSON text.

Aliases

comptime NULL = Int(0)

comptime BOOLEAN = Int(1)

comptime INT = Int(2)

comptime LONG = Int(3)

comptime FLOAT = Int(4)

comptime DOUBLE = Int(5)

comptime BYTES = Int(6)

comptime STRING = Int(7)

comptime RECORD = Int(8)

comptime ENUM = Int(9)

comptime ARRAY = Int(10)

comptime MAP = Int(11)

comptime UNION = Int(12)

comptime FIXED = Int(13)