Icon LinkHash based IDs

Hash based ids are deterministically generated from associated types and are used in the JSON ABI for type IDs and for logId. This document specifies how the hash based IDS are generated for type IDs and for logId.

Icon LinkGeneration

Hash based ids for type IDs are generated from the sha256 of a string that represents the type.

For logIds we use the first 8 bytes of the sha256 of a string that represents the type, this is because the LOG and LOGD opcodes use a 64bit value as log id.

Icon LinkString representation of types

For describing the string representation of type we will use the notation {abi_str(T)} that should be replaced by the respective ABI string representation of the respective type T.

Icon LinkIntrinsics

u8 => "u8" u16 => "u16" u32 => "u32" u64 => "u64" u256 => "u256" b256 => "b256" bool => "bool"

Icon LinkString arrays

String array of size 1 => "str[1]" String array of size 2 => "str[2]" etc.

Icon LinkString slices

String slice => "str"

Icon LinkArrays

[T; 1] => "[{abi_str(T)}; 1]" [T; 2] => "[{abi_str(T)}; 2]" etc.

Icon LinkTuples

() => "()" (T1) => "({abi_str(T1)})" (T1,T2) => "({abi_str(T1)}, {abi_str(T2)})" etc.

Icon LinkEnums

Option enum with type parameter T => "enum std::option::Option<{abi_str(T)}>" Enum without type parameters named MyEnum => "enum MyEnum" Enum with type parameter T1 named MyEnum => "enum MyEnum<{abi_str(T1)}>" Enum with type parameters T1, T2 named MyEnum in my_module => "enum my_module::MyEnum<{abi_str(T1)},{abi_str(T2)}>"

Icon LinkStructs

Vec struct with type parameter T => "struct std::vec::Vec<{abi_str(T)}>" Struct without type parameters named MyStruct => "struct MyStruct" Struct with type parameter T1 named MyStruct => "struct MyStruct<{abi_str(T1)}>" Struct with type parameters T1, T2 named MyStruct in my_module => "struct my_module::MyStruct<{abi_str(T1)},{abi_str(T2)}>"

Icon LinkGeneric Type Parameter

Generic type parameter T if root type => "generic T" Generic type parameter T if not root type => "T" as in "struct MyStruct<T>"

Icon LinkComplex examples composition

Tuple of array and u64 => "([u64,1]; u64)" Array of Option<u64>=> "[enum std::option::Option<u64>; 3]" Struct with tuple type parameter => "struct my_module::MyStruct<(u64, u64)>"