cerc-io/solidity
16
0
Fork 0
mirror of https://github.com/ethereum/solidity synced 2023-10-03 13:03:40 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Bring inheritance doc inline with style guide

Browse Source
This commit is contained in:
Chris Ward 2019-05-27 14:23:53 +02:00
parent be653bec44
commit 3b64a4b955
1 changed files with 17 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
docs/contracts/inheritance.rst
View File

@ -27,21 +27,24 @@ Details are given in the following example.
pragma solidity >=0.5.0 <0.7.0; pragma solidity >=0.5.0 <0.7.0;
contract owned {
contract Owned {
constructor() public { owner = msg.sender; } constructor() public { owner = msg.sender; }
address payable owner; address payable owner;
} }
// Use `is` to derive from another contract. Derived // Use `is` to derive from another contract. Derived
// contracts can access all non-private members including // contracts can access all non-private members including
// internal functions and state variables. These cannot be // internal functions and state variables. These cannot be
// accessed externally via `this`, though. // accessed externally via `this`, though.
contract mortal is owned { contract Mortal is Owned {
function kill() public { function kill() public {
if (msg.sender == owner) selfdestruct(owner); if (msg.sender == owner) selfdestruct(owner);
} }
} }
// These abstract contracts are only provided to make the // These abstract contracts are only provided to make the
// interface known to the compiler. Note the function // interface known to the compiler. Note the function
// without body. If a contract does not implement all // without body. If a contract does not implement all
@ -50,15 +53,17 @@ Details are given in the following example.
function lookup(uint id) public returns (address adr); function lookup(uint id) public returns (address adr);
} }
contract NameReg { contract NameReg {
function register(bytes32 name) public; function register(bytes32 name) public;
function unregister() public; function unregister() public;
} }
// Multiple inheritance is possible. Note that `owned` is // Multiple inheritance is possible. Note that `owned` is
// also a base class of `mortal`, yet there is only a single // also a base class of `mortal`, yet there is only a single
// instance of `owned` (as for virtual inheritance in C++). // instance of `owned` (as for virtual inheritance in C++).
contract named is owned, mortal { contract Named is Owned, Mortal {
constructor(bytes32 name) public { constructor(bytes32 name) public {
Config config = Config(0xD5f9D8D94886E70b06E474c3fB14Fd43E2f23970); Config config = Config(0xD5f9D8D94886E70b06E474c3fB14Fd43E2f23970);
NameReg(config.lookup(1)).register(name); NameReg(config.lookup(1)).register(name);
@ -75,22 +80,23 @@ Details are given in the following example.
NameReg(config.lookup(1)).unregister(); NameReg(config.lookup(1)).unregister();
// It is still possible to call a specific // It is still possible to call a specific
// overridden function. // overridden function.
mortal.kill(); Mortal.kill();
} }
} }
} }
// If a constructor takes an argument, it needs to be // If a constructor takes an argument, it needs to be
// provided in the header (or modifier-invocation-style at // provided in the header (or modifier-invocation-style at
// the constructor of the derived contract (see below)). // the constructor of the derived contract (see below)).
contract PriceFeed is owned, mortal, named("GoldFeed") { contract PriceFeed is Owned, Mortal, Named("GoldFeed") {
function updateInfo(uint newInfo) public { function updateInfo(uint newInfo) public {
if (msg.sender == owner) info = newInfo; if (msg.sender == owner) info = newInfo;
} }
function get() public view returns(uint r) { return info; } function get() public view returns(uint r) { return info; }
uint info; uint info;
} }
Note that above, we call ``mortal.kill()`` to "forward" the Note that above, we call ``mortal.kill()`` to "forward" the