```
interface Hashable
"""
Anything with a hash method is hashable.
"""
fun hash(): USize
interface Hashable64
"""
A version of Hashable that returns 64-bit hashes on every platform.
"""
fun hash64(): U64
interface val HashFunction[A]
"""
A pluggable hash function.
"""
new val create()
"""
Data structures create instances internally. Use a primitive if possible.
"""
fun hash(x: box->A!): USize
"""
Calculate the hash of some type. This is an alias of the type parameter to
allow data structures to hash things without consuming them.
"""
fun eq(x: box->A!, y: box->A!): Bool
"""
Determine equality between two keys with the same hash. This is done with
viewpoint adapted aliases to allow data structures to determine equality
in a box fun without consuming keys.
"""
interface val HashFunction64[A]
"""
A pluggable hash function with 64-bit hashes.
"""
new val create()
"""
Data structures create instances internally. Use a primitive if possible.
"""
fun hash64(x: box->A!): U64
"""
Calculate the hash of some type. This is an alias of the type parameter to
allow data structures to hash things without consuming them.
"""
fun eq(x: box->A!, y: box->A!): Bool
"""
Determine equality between two keys with the same hash. This is done with
viewpoint adapted aliases to allow data structures to determine equality
in a box fun without consuming keys.
"""
primitive HashEq[A: (Hashable #read & Equatable[A] #read)] is HashFunction[A]
fun hash(x: box->A): USize =>
"""
Use the hash function from the type parameter.
"""
x.hash()
fun eq(x: box->A, y: box->A): Bool =>
"""
Use the structural equality function from the type parameter.
"""
x == y
primitive HashEq64[A: (Hashable64 #read & Equatable[A] #read)] is
HashFunction64[A]
fun hash64(x: box->A): U64 =>
"""
Use the hash function from the type parameter.
"""
x.hash64()
fun eq(x: box->A, y: box->A): Bool =>
"""
Use the structural equality function from the type parameter.
"""
x == y
primitive HashIs[A] is (HashFunction[A] & HashFunction64[A])
fun hash(x: box->A!): USize =>
"""
Hash the identity rather than the contents.
"""
(digestof x).hash()
fun hash64(x: box->A!): U64 =>
"""
Hash the identity rather than the contents.
"""
(digestof x).hash64()
fun eq(x: box->A!, y: box->A!): Bool =>
"""
Determine equality by identity rather than structurally.
"""
x is y
primitive HashByteSeq is
(HashFunction[ByteSeq box] & HashFunction64[ByteSeq box])
"""
Hash and equality functions for arbitrary ByteSeq.
"""
fun hash(x: ByteSeq box): USize =>
@ponyint_hash_block[USize](x.cpointer(), x.size())
fun hash64(x: ByteSeq box): U64 =>
@ponyint_hash_block64[U64](x.cpointer(), x.size())
fun eq(x: ByteSeq box, y: ByteSeq box): Bool =>
if x.size() == y.size() then
@memcmp[I32](x.cpointer(), y.cpointer(), x.size()) == 0
else
false
end
```