Basic data types
The contract platform of Ant Blockchain supports almost all data types in Solidity. However, some user-defined input parameter types are not supported, for example, the two-dimensional arrays. The contract platform also provides the identity type that contains a 32-byte string to identify each user. The address type in Solidity is not supported.
We recommend that you use the following data types:
Type | Sample | Supported by the contract platform | Supported as an input parameter |
bool | bool a = true | Yes | Yes |
uint | uint a = 1 | Yes | Yes |
uint8 ~ uint256 | uint8 a = 1 | Yes | Yes |
int | int a = 1 | Yes | Yes |
int8 ~ int256 | int8 a = 1 | Yes | Yes |
bytes | bytes a = “test” | Yes | Yes |
bytes1 ~ bytes32 | bytes1 a = “a” | Yes | Yes |
string | string a = “test” | Yes | Yes |
identity | identity id = 0x1234567890123456789012345678901234567890123456789012345678901234567890000 | Yes | Yes |
int[] | int256[] a = [1,2,3,4,5] | Yes | Yes |
uint[] | uint256[] a = [1,2,3,4,5] | Yes | Yes |
bytes1[] ~ bytes32[] | bytes4[] asd = new bytes4; | Yes | Yes |
string[] | string[] a = [“adbc”,”dg”] | Yes | No |
enum | enum a {a,b,c} | Yes | No |
struct | struct a { string name;} | Yes | No |
These data types are used within the contract.
Input parameters: The parameters passed in when a method is called on the client.
For example, in the issuance methods of the credit management contract, the identity type and the int256 type are both input parameter types and supported by the contract platform.
function Issue(identity account, int256 value)The mapping declaration type corresponding to the user credits and the account ID can be used within a contract. However, the mapping declaration type cannot be used as an input type for a function. For example:
function example(mapping(identity=>int256) map) // An error occurred. The mapping declaration type is not supported as an input type.Other types
Solidity also supports other data types, including:
mapping
struct
Units of time: seconds, minutes, hours, days, weeks, and years.
For more information, see Data types supported in Solidity (English).