precompile

This module implements precompiled contracts in the EVM, adding a layer of pre-set functionalities. These are documented in more detail in the next section. The module defines the types and the enum that are used to handle precompiled contracts.

PrecompileResult: This is a type alias for a Result type. The Ok variant of this type contains a tuple (u64, Vec<u8>), where the u64 integer likely represents gas used by the precompiled contract, and the Vec<u8> holds the output data. The Err variant contains a PrecompileError.

StandardPrecompileFn and CustomPrecompileFn: These are type aliases for function pointers. Both functions take a byte slice and a u64 (probably the available gas) as arguments and return a PrecompileResult. The naming suggests that the former refers to built-in precompiled contracts, while the latter may refer to custom, user-defined contracts.

PrecompileError: This is an enumeration (enum) which describes the different types of errors that could occur while executing a precompiled contract. The listed variants suggest these errors are related to gas consumption, Blake2 hash function, modular exponentiation ("Modexp"), and Bn128, which is a specific elliptic curve used in cryptography.