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authorJim McDonald <Jim@mcdee.net>2017-12-13 02:47:30 +0800
committerJim McDonald <Jim@mcdee.net>2017-12-13 02:47:30 +0800
commit6e521d59b0a30fa0673aaf84559d5b74dbb1eed7 (patch)
tree618b00999c2de8432f222c7b990f51ef4de6b1f0 /docs/control-structures.rst
parent7614b16dc9b2bb1e267e8f46834b40220fb9f9fb (diff)
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Fix Solidity warnings
Diffstat (limited to 'docs/control-structures.rst')
-rw-r--r--docs/control-structures.rst58
1 files changed, 31 insertions, 27 deletions
diff --git a/docs/control-structures.rst b/docs/control-structures.rst
index bcb597cf..079b14c7 100644
--- a/docs/control-structures.rst
+++ b/docs/control-structures.rst
@@ -20,10 +20,10 @@ For example, suppose we want our contract to
accept one kind of external calls with two integers, we would write
something like::
- pragma solidity ^0.4.0;
+ pragma solidity ^0.4.16;
contract Simple {
- function taker(uint _a, uint _b) {
+ function taker(uint _a, uint _b) public pure {
// do something with _a and _b.
}
}
@@ -36,10 +36,14 @@ The output parameters can be declared with the same syntax after the
the sum and the product of the two given integers, then we would
write::
- pragma solidity ^0.4.0;
+ pragma solidity ^0.4.16;
contract Simple {
- function arithmetics(uint _a, uint _b) returns (uint o_sum, uint o_product) {
+ function arithmetics(uint _a, uint _b)
+ public
+ pure
+ returns (uint o_sum, uint o_product)
+ {
o_sum = _a + _b;
o_product = _a * _b;
}
@@ -95,11 +99,11 @@ Internal Function Calls
Functions of the current contract can be called directly ("internally"), also recursively, as seen in
this nonsensical example::
- pragma solidity ^0.4.0;
+ pragma solidity ^0.4.16;
contract C {
- function g(uint a) returns (uint ret) { return f(); }
- function f() returns (uint ret) { return g(7) + f(); }
+ function g(uint a) public pure returns (uint ret) { return f(); }
+ function f() internal pure returns (uint ret) { return g(7) + f(); }
}
These function calls are translated into simple jumps inside the EVM. This has
@@ -125,13 +129,13 @@ the gas can be specified with special options ``.value()`` and ``.gas()``, respe
pragma solidity ^0.4.0;
contract InfoFeed {
- function info() payable returns (uint ret) { return 42; }
+ function info() public payable returns (uint ret) { return 42; }
}
contract Consumer {
InfoFeed feed;
- function setFeed(address addr) { feed = InfoFeed(addr); }
- function callFeed() { feed.info.value(10).gas(800)(); }
+ function setFeed(address addr) public { feed = InfoFeed(addr); }
+ function public callFeed() { feed.info.value(10).gas(800)(); }
}
The modifier ``payable`` has to be used for ``info``, because otherwise, the `.value()`
@@ -180,11 +184,11 @@ parameters from the function declaration, but can be in arbitrary order.
pragma solidity ^0.4.0;
contract C {
- function f(uint key, uint value) {
+ function f(uint key, uint value) public {
// ...
}
- function g() {
+ function g() public {
// named arguments
f({value: 2, key: 3});
}
@@ -198,11 +202,11 @@ Those parameters will still be present on the stack, but they are inaccessible.
::
- pragma solidity ^0.4.0;
+ pragma solidity ^0.4.16;
contract C {
// omitted name for parameter
- function func(uint k, uint) returns(uint) {
+ function func(uint k, uint) public pure returns(uint) {
return k;
}
}
@@ -225,7 +229,7 @@ creation-dependencies are not possible.
contract D {
uint x;
- function D(uint a) payable {
+ function D(uint a) public payable {
x = a;
}
}
@@ -233,11 +237,11 @@ creation-dependencies are not possible.
contract C {
D d = new D(4); // will be executed as part of C's constructor
- function createD(uint arg) {
+ function createD(uint arg) public {
D newD = new D(arg);
}
- function createAndEndowD(uint arg, uint amount) payable {
+ function createAndEndowD(uint arg, uint amount) public payable {
// Send ether along with the creation
D newD = (new D).value(amount)(arg);
}
@@ -270,16 +274,16 @@ Destructuring Assignments and Returning Multiple Values
Solidity internally allows tuple types, i.e. a list of objects of potentially different types whose size is a constant at compile-time. Those tuples can be used to return multiple values at the same time and also assign them to multiple variables (or LValues in general) at the same time::
- pragma solidity ^0.4.0;
+ pragma solidity ^0.4.16;
contract C {
uint[] data;
- function f() returns (uint, bool, uint) {
+ function f() public pure returns (uint, bool, uint) {
return (7, true, 2);
}
- function g() {
+ function g() public {
// Declares and assigns the variables. Specifying the type explicitly is not possible.
var (x, b, y) = f();
// Assigns to a pre-existing variable.
@@ -326,10 +330,10 @@ As a result, the following code is illegal and cause the compiler to throw an er
// This will not compile
- pragma solidity ^0.4.0;
+ pragma solidity ^0.4.16;
contract ScopingErrors {
- function scoping() {
+ function scoping() public {
uint i = 0;
while (i++ < 1) {
@@ -341,7 +345,7 @@ As a result, the following code is illegal and cause the compiler to throw an er
}
}
- function minimalScoping() {
+ function minimalScoping() public {
{
uint same2 = 0;
}
@@ -351,7 +355,7 @@ As a result, the following code is illegal and cause the compiler to throw an er
}
}
- function forLoopScoping() {
+ function forLoopScoping() public {
for (uint same3 = 0; same3 < 1; same3++) {
}
@@ -364,9 +368,9 @@ In addition to this, if a variable is declared, it will be initialized at the be
As a result, the following code is legal, despite being poorly written::
pragma solidity ^0.4.0;
-
+
contract C {
- function foo() returns (uint) {
+ function foo() public pure returns (uint) {
// baz is implicitly initialized as 0
uint bar = 5;
if (true) {
@@ -412,7 +416,7 @@ and how ``assert`` can be used for internal error checking::
pragma solidity ^0.4.0;
contract Sharer {
- function sendHalf(address addr) payable returns (uint balance) {
+ function sendHalf(address addr) public payable returns (uint balance) {
require(msg.value % 2 == 0); // Only allow even numbers
uint balanceBeforeTransfer = this.balance;
addr.transfer(msg.value / 2);