Whitepaper - Ethereum Classic With Cover

Ethereum Classic Documentation, Release 0.1
Mutan (deprecated)
Mutan is a statically typed, C-like language designed and developed by Jeffrey Wilcke. It is no longer maintained.
Writing a contract
No language would be complete without a Hello World program. Operating within the Ethereum environment,
Solidity has no obvious way of “outputting” a string. The closest we can do is to use a log event to place a string
into the blockchain:
contract HelloWorld {
event Print(string out);
function() { Print("Hello, World!"); }
}
This contract will create a log entry on the blockchain of type Print with a parameter “Hello, World!” each time it
is executed.
See also:
Solidity docs has more examples and guidelines to writing Solidity code.
Compiling a contract
Compilation of solidity contracts can be accomplished via a number of mechanisms.
• Using the solc compiler via the command line.
• Using web3.eth.compile.solidity in the javascript console provided by geth or eth (This still
requires the solc compiler to be installed).
• The online Solidity realtime compiler.
• The Meteor dapp Cosmo for building solidity contracts.
• The Mix IDE.
• The Ethereum Wallet.
Note: More information on solc and compiling Solidity contract code can be found here.
Setting up the solidity compiler in geth
If you start up your geth node, you can check which compilers are available.
> web3.eth.getCompilers();
["lll", "solidity", "serpent"]
This command returns an array of strings indicating which compilers are currently available.
Note: The solc compiler is installed with cpp-ethereum. Alternatively, you can build it yourself.
If your solc executable is in a non-standard location you can specify a custom path to the solc executable using
th --solc flag.
$ geth --solc /usr/local/bin/solc
Alternatively, you can set this option at runtime via the console:
80 Chapter 1. Contents