miguelmota/solidity-idiosyncrasies

Solidity gotchas, pitfalls, limitations, and idiosyncrasies.

solidity-idiosyncrasies's Issues

String comparison

Hey Miguel, I just stumbled upon this awesome repo. Congrats on putting this together.

About the string comparison:

Can't compare two strings; one workaround is to compare the sha3 hashes of the strings.

I've seen you mentioned string-utils from Nick Johnson but his assembly code will soon-ish not compile anymore (since it makes use of jump/jumpi instructions which will be deprecated).

Also I'll do a shameless plug here and say that my version of the bytes arrays handling lib outperforms comparison with the keccak256 function for strings both in memory or in storage. 😄

https://github.com/GNSPS/solidity-bytes-utils/blob/master/contracts/BytesLib.sol#L286
&
https://github.com/GNSPS/solidity-bytes-utils/blob/master/contracts/BytesLib.sol#L329

Implicit initial value - is it 0? Or not always?

Found strange that initial values are implicit:

contract x{
    uint num; //initial value is 0
    function inc(){
        num++;
    }
}

String length

Just a note on type casting a string to bytes and then using the length member, it doesn't actually count characters but bytes which in unicode strings are not exactly the same thing. 😄

(Coming from a guy called Gonçalo)