Returning arbitrary length bytes instead of bytes32

[snario]

As a means of generalizing the conditional execution object to something nicely usable by other projects in the community such as state channels or Plasma contracts, or perhaps within future extensions of this project, it would be nice if callWithData returned bytes using returndatasize.

[kosecki123]

Agree, that would be more general approach to conditionals. The reason for returning bytes32 is we want to get true/false value from the condition.

In order to allow reading bytes from call take a look at this quick'n'dirty test code:

contract Test1 {
    function add(int a, int b) returns(bytes){  //Simply add the two arguments and return
        return abi.encode(a+b);
    }
}

contract Test2 {
    Test1 test1;

    function Test2(){
        test1 = new Test1(); 
    }
    
    function testAdd() constant returns(bytes) {
        //encoded add(int256,int256) call add(2,2) expected return 4
        bytes memory a = hex"a5f3c23b00000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000002";
        return callWithData(address(test1), a);
    }
  
    function callWithData(address dest, bytes data) private returns (bytes c) {
        assembly {
            let freemem := mload(0x40)
            
            pop(
            call(      
                5000,
                dest,
                0,
                add(data, 0x20),
                mload(data),
                0,
                0
            )
            )
            
            let size := returndatasize
            returndatacopy(freemem, 0, size)
            
            return (freemem, size)
        }
    }
}