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Diffstat (limited to 'solidity.html.markdown')
| -rw-r--r-- | solidity.html.markdown | 48 |
1 files changed, 29 insertions, 19 deletions
diff --git a/solidity.html.markdown b/solidity.html.markdown index a0f8cd40..d215180d 100644 --- a/solidity.html.markdown +++ b/solidity.html.markdown @@ -4,6 +4,8 @@ filename: learnSolidity.sol contributors: - ["Nemil Dalal", "https://www.nemil.com"] - ["Joseph Chow", ""] + - ["Bhoomtawath Plinsut", "https://github.com/varshard"] + - ["Shooter", "https://github.com/liushooter"] --- Solidity lets you program on [Ethereum](https://www.ethereum.org/), a @@ -109,9 +111,9 @@ contract SimpleBank { // CapWords /// @notice Get balance /// @return The balance of the user - // 'constant' prevents function from editing state variables; + // 'view' (ex: constant) prevents function from editing state variables; // allows function to run locally/off blockchain - function balance() constant public returns (uint) { + function balance() view public returns (uint) { return balances[msg.sender]; } } @@ -134,7 +136,7 @@ uint constant VERSION_ID = 0x123A1; // A hex constant // All state variables (those outside a function) // are by default 'internal' and accessible inside contract // and in all contracts that inherit ONLY -// Need to explicitly set to 'public' to allow external contracts to access +// Need to explicitly set to 'public' to allow external contracts to access int256 public a = 8; // For int and uint, can explicitly set space in steps of 8 up to 256 @@ -236,7 +238,7 @@ uint x[][5]; // arr with 5 dynamic array elements (opp order of most languages) // Dictionaries (any type to any other type) mapping (string => uint) public balances; balances["charles"] = 1; -console.log(balances["ada"]); // is 0, all non-set key values return zeroes +// balances["ada"] result is 0, all non-set key values return zeroes // 'public' allows following from another contract contractName.balances("charles"); // returns 1 // 'public' created a getter (but not setter) like the following: @@ -341,25 +343,26 @@ function increment(uint x, uint y) returns (uint x, uint y) { // Call previous functon uint (a,b) = increment(1,1); -// 'constant' (alias for 'view') +// 'view' (alias for 'constant') // indicates that function does not/cannot change persistent vars -// Constant function execute locally, not on blockchain +// View function execute locally, not on blockchain +// Noted: constant keyword will soon be deprecated. uint y = 1; -function increment(uint x) constant returns (uint x) { +function increment(uint x) view returns (uint x) { x += 1; y += 1; // this line would fail - // y is a state variable, and can't be changed in a constant function + // y is a state variable, and can't be changed in a view function } -// 'pure' is more strict than 'constant', and does not +// 'pure' is more strict than 'view' or 'constant', and does not // even allow reading of state vars // The exact rules are more complicated, so see more about -// constant/pure: +// view/pure: // http://solidity.readthedocs.io/en/develop/contracts.html#view-functions // 'Function Visibility specifiers' -// These can be placed where 'constant' is, including: +// These can be placed where 'view' is, including: // public - visible externally and internally (default for function) // external - only visible externally (including a call made with this.) // private - only visible in the current contract @@ -384,7 +387,7 @@ function depositEther() public payable { // Prefer loops to recursion (max call stack depth is 1024) -// Also, don't setup loops that you haven't bounded, +// Also, don't setup loops that you haven't bounded, // as this can hit the gas limit // B. Events @@ -399,11 +402,15 @@ function depositEther() public payable { event LogSent(address indexed from, address indexed to, uint amount); // note capital first letter // Call -Sent(from, to, amount); +LogSent(from, to, amount); -// For an external party (a contract or external entity), to watch using -// the Web3 Javascript library: -Coin.Sent().watch({}, '', function(error, result) { +/** + +For an external party (a contract or external entity), to watch using +the Web3 Javascript library: + +// The following is Javascript code, not Solidity code +Coin.LogSent().watch({}, '', function(error, result) { if (!error) { console.log("Coin transfer: " + result.args.amount + " coins were sent from " + result.args.from + @@ -413,6 +420,8 @@ Coin.Sent().watch({}, '', function(error, result) { "Receiver: " + Coin.balances.call(result.args.to)); } } +**/ + // Common paradigm for one contract to depend on another (e.g., a // contract that depends on current exchange rate provided by another) @@ -709,7 +718,7 @@ contract CrowdFunder { return contributions.length - 1; // return id } - function checkIfFundingCompleteOrExpired() + function checkIfFundingCompleteOrExpired() public { if (totalRaised > minimumToRaise) { @@ -829,7 +838,7 @@ someContractAddress.callcode('function_name'); ## Additional resources - [Solidity Docs](https://solidity.readthedocs.org/en/latest/) - [Smart Contract Best Practices](https://github.com/ConsenSys/smart-contract-best-practices) -- [Solidity Style Guide](https://ethereum.github.io/solidity//docs/style-guide/): Ethereum's style guide is heavily derived from Python's [pep8](https://www.python.org/dev/peps/pep-0008/) style guide. +- [Superblocks Lab - Browser based IDE for Solidity](https://lab.superblocks.com/) - [EthFiddle - The JsFiddle for Solidity](https://ethfiddle.com/) - [Browser-based Solidity Editor](https://remix.ethereum.org/) - [Gitter Solidity Chat room](https://gitter.im/ethereum/solidity) @@ -850,9 +859,10 @@ someContractAddress.callcode('function_name'); - [Hacking Distributed Blog](http://hackingdistributed.com/) ## Style -- Python's [PEP8](https://www.python.org/dev/peps/pep-0008/) is used as the baseline style guide, including its general philosophy +- [Solidity Style Guide](http://solidity.readthedocs.io/en/latest/style-guide.html): Ethereum's style guide is heavily derived from Python's [PEP 8](https://www.python.org/dev/peps/pep-0008/) style guide. ## Editors +- [Emacs Solidity Mode](https://github.com/ethereum/emacs-solidity) - [Vim Solidity](https://github.com/tomlion/vim-solidity) - Editor Snippets ([Ultisnips format](https://gist.github.com/nemild/98343ce6b16b747788bc)) |