Migrating from Solidity

Solidity Compatibility

Solidity++ 0.8 is compatible with almost all syntax of Solidity, except for a few differences which will be introduced below.

All features related to Ethereum are replaced with the counterparts in Vite.

Note: The new keyword is disabled in this version. In other words, it is impossible to deploy a new contract from a contract at runtime. In addition, selfdestruct and ecrecover are disabled in this version.

Types

Type address is redefined to be compatible with Vite, and a new type vitetoken representing Vite Native Token Id is introduced in Solidity++.

Copy // address type address addr1 = address("vite_0102030405060708090807060504030201020304eddd83748e"); address addr2 = "vite_0102030405060708090807060504030201020304eddd83748e"; address payable addr3 = payable("vite_0102030405060708090807060504030201020304eddd83748e"); // vitetoken type vitetoken token1 = vitetoken("tti_2445f6e5cde8c2c70e446c83"); vitetoken token2 = "tti_2445f6e5cde8c2c70e446c83";

Call Options

When calling functions of other contracts, it is possible to specify the amount of a specific token sent with the call in call options, e.g. {token: "tti_564954455820434f494e69b5", value: 1e18}.

Copy // SPDX-License-Identifier: GPL-3.0 pragma soliditypp >=0.8.0 <0.9.0; contract InfoFeed { function info() external async payable returns (uint ret) { return 42; } } contract Consumer { InfoFeed feed; constructor payable (address payable addr) { feed = InfoFeed(addr); } function callFeed() external async { // send 1 VX with the call feed.info{token: "tti_564954455820434f494e69b5", value: 1e18}(); } }

If property token is omitted, the VITE token is sent by default.

That says, the following code

Copy feed.info{value: 1e18}();

is equivalents to

Copy feed.info{token: "tti_5649544520544f4b454e6e40", value: 1e18}();

Notice

Property gas and salt in call option are not supported in Solidity++.

Units

In Solidity, a literal number can take a suffix of wei, gwei or ether to specify a subdenomination of Ether, where Ether numbers without a postfix are assumed to be wei.

Similarly, in Solidity++, a literal number can take a suffix of attov and vite to specify a subdenomination of VITE, where VITE numbers without a postfix are assumed to be attov.

Copy 1 vite = 1e18 attov

Special Variables and Functions

Block and Transaction Properties

Below special variables and functions has been removed in Solidity++:

Copy tx.gasprice; block.coinbase; block.difficulty; block.gaslimit; blockhash(param); gasleft(); msg.gas; selfdestruct(_owner); suicide(_addr);

Below special variables and functions has been added in Solidity++:

Copy bytes32 b1 = fromhash(); uint height = accountheight(); bytes32 b2 = prevhash(); uint64 random = random64(); uint64 random = nextrandom();

• fromhash() returns request transaction's hash
• accountheight() returns latest block height of an account
• prevhash() returns latest block hash of an account
• random64() returns a random number in uint64. This function will return the same random number in one transaction
• nextrandom() returns a random number in uint64. This function can be called multiple times to obtain different random numbers in one transaction

Get transfer value (Ether) in Solidity:

Copy uint amount = msg.value

Get transfer value and token id in Solidity++:

Copy uint amount = msg.value; vitetoken token = msg.token;

Members of Address Types

Get account balance in Solidity:

Copy address.balance

Get account balance in Solidity++, balance is a function with a single parameter of vitetoken:

Copy address.balance("tti_564954455820434f494e69b5");

In Solidity, send Ether to an address:

Copy payable(_addr).transfer(_amount);

In Solidity++, send some amount of a specific token to an address:

Copy payable(_addr).transfer(_tokenId, _amount);

Cryptographic Functions

A new hash function blake2b is introduced in Solidity++.

Copy blake2b(bytes memory) returns (bytes32)

• Compute the Blake2b hash of the input.