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Diffstat (limited to 'docs/contracts.rst')
-rw-r--r-- | docs/contracts.rst | 40 |
1 files changed, 31 insertions, 9 deletions
diff --git a/docs/contracts.rst b/docs/contracts.rst index 121c4de0..f8a44fb3 100644 --- a/docs/contracts.rst +++ b/docs/contracts.rst @@ -40,7 +40,7 @@ This means that cyclic creation dependencies are impossible. :: - pragma solidity ^0.4.16; + pragma solidity >0.4.21; contract OwnedToken { // TokenCreator is a contract type that is defined below. @@ -52,7 +52,7 @@ This means that cyclic creation dependencies are impossible. // This is the constructor which registers the // creator and the assigned name. - function OwnedToken(bytes32 _name) public { + constructor(bytes32 _name) public { // State variables are accessed via their name // and not via e.g. this.owner. This also applies // to functions and especially in the constructors, @@ -679,7 +679,7 @@ candidate, resolution fails. } } -Calling ``f(50)`` would create a type error since ``250`` can be implicitly converted both to ``uint8`` +Calling ``f(50)`` would create a type error since ``50`` can be implicitly converted both to ``uint8`` and ``uint256`` types. On another hand ``f(256)`` would resolve to ``f(uint256)`` overload as ``256`` cannot be implicitly converted to ``uint8``. @@ -803,7 +803,7 @@ as topics. The event call above can be performed in the same way as } where the long hexadecimal number is equal to -``keccak256("Deposit(address,hash256,uint256)")``, the signature of the event. +``keccak256("Deposit(address,bytes32,uint256)")``, the signature of the event. Additional Resources for Understanding Events ============================================== @@ -976,8 +976,31 @@ virtual method lookup. Constructors ============ -A constructor is an optional function with the same name as the contract which is executed upon contract creation. -Constructor functions can be either ``public`` or ``internal``. +A constructor is an optional function declared with the ``constructor`` keyword which is executed upon contract creation. +Constructor functions can be either ``public`` or ``internal``. If there is no constructor, the contract will assume the +default constructor: ``contructor() public {}``. + + +:: + + pragma solidity >0.4.21; + + contract A { + uint public a; + + constructor(uint _a) internal { + a = _a; + } + } + + contract B is A(1) { + constructor() public {} + } + +A constructor set as ``internal`` causes the contract to be marked as :ref:`abstract <abstract-contract>`. + +.. note :: + Prior to version 0.4.22, constructors were defined as functions with the same name as the contract. This syntax is now deprecated. :: @@ -995,7 +1018,6 @@ Constructor functions can be either ``public`` or ``internal``. function B() public {} } -A constructor set as ``internal`` causes the contract to be marked as :ref:`abstract <abstract-contract>`. .. index:: ! base;constructor @@ -1009,11 +1031,11 @@ the base constructors. This can be done in two ways:: contract Base { uint x; - function Base(uint _x) public { x = _x; } + constructor(uint _x) public { x = _x; } } contract Derived is Base(7) { - function Derived(uint _y) Base(_y * _y) public { + constructor(uint _y) Base(_y * _y) public { } } |