[Ethereum] How to access public variables, and getting return values in smart contracts

contract-developmentsolidity

Say I have a smart contract such as:

contact Rabbit {
    string public name;

    function setName(string n) returns (bool) {
        name = n;
        return true;
    }
}

How can I get the value of name after having set it? I'm using Truffle. I've tried (where rabbit is a handle of Rabbit:

rabbit.name();

This just returns ''.

Also, how can I get the return value? If I execute setName I just see the transaction, not the return value. I read somewhere I can use call(), such as: rabbit.setName.call("barry"), though it wont save the transaction so it needs ot be call again, without call(). Have I got this wrong?

Thanks.

Best Answer

Insertion can be done using sendTransaction function.

 Rabbit.deployed().then(function(contract) {contract.createProperty("Hello",{from: web3.eth.accounts[0]}).then(function(v) {console.log(v)})})

You can use call method to get the value of public variable.Try the below command in truffle console.

 Rabbit.deployed().then(function(contract)  {contract.name.call().then(function(v) {console.log(v)})})

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[Ethereum] Contract with mapping(address->bool) does not work as expected

Did you run your code locally or in memory(VM) or into the blockchain? I tried your code it seems working (0=false before granting access and 1=true after)

Try to add an event to your grantaccess function;

  event ev(bool is_granted)
  function grantAccess(address assetAddr) {
        registry[assetAddr] = true;
        ev(registry[assetAddr]);
    }

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The problem is that totalSupply() implementation is missing. Seems like autogenerated getters do not count. So you need to explicitly create the function.

contract StandardToken is Token {
    uint256 _totalSupply;

    function totalSupply() constant returns (uint256 totalSupply) {
        totalSupply = _totalSupply;
    }
}

Best Answer

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