小编0xF*_*0xF的帖子

为了git cherry-pick导致冲突,为什么Git建议的更改不仅仅来自给定的提交？

例:

-bash-4.2$ git init
Initialized empty Git repository in /home/pfusik/cp-so/.git/
-bash-4.2$ echo one >f
-bash-4.2$ git add f
-bash-4.2$ git commit -m "one"
[master (root-commit) d65bcac] one
 1 file changed, 1 insertion(+)
 create mode 100644 f
-bash-4.2$ git checkout -b foo
Switched to a new branch 'foo'
-bash-4.2$ echo two >>f
-bash-4.2$ git commit -a -m "two"
[foo 346ce5e] two
 1 file changed, 1 insertion(+)
-bash-4.2$ echo three >>f
-bash-4.2$ git commit -a -m "three"
[foo …

我知道我可以使用以下方法创建表达式树

1. 工厂方法.

2. 编译器将lambda表达式转换为Expression.

对于复杂的表达式树,我更喜欢2,因为它更简洁.

是否可以Expressions使用这种方式引用已构建的？

using System;
using System.Linq.Expressions;

public class Test
{
    public static Expression<Func<int, int>> Add(Expression expr)
    {
#if false
        // works
        ParameterExpression i = Expression.Parameter(typeof(int));
        return Expression.Lambda<Func<int, int>>(Expression.Add(i, expr), i);
#else
        // compiler error, can I pass expr here somehow?
        return i => i + expr;
#endif
    }

    public static void Main()
    {
        Func<int, int> f = Add(Expression.Constant(42)).Compile();
        Console.WriteLine(f(1));
    }
}

我有一个关于转发引用的具体问题。（我认为）我理解 r 值引用和std::move，但我无法理解转发引用：

#include <iostream>
#include <utility>

template <typename T> class TD; // from "Effective Modern C++"

void consume(const int &i) { std::cout << "lvalue\n"; }
void consume(int &&i)      { std::cout << "rvalue\n"; }

template <typename T>
void foo(T&& x) {
//    TD<decltype(x)> xType; - prints int&&
    consume(x);
}

int main() {
    foo(1 + 2);
}

T是int，没关系。如果x是 type int&&，为什么它打印“lvalue”而我们需要std::forward？我的意思是，从哪里转换int&&到const int&这里？

我想将SVG中的实心方块彼此相邻放置,但它们之间有细线.如何消除这些线？

例:

<svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="3cm" height="3cm" viewBox="0 0 10 10">
    <rect x="0" y="0" width="1" height="1" fill="black" />
    <rect x="2" y="0" width="1" height="1" fill="black" />
    <rect x="4" y="0" width="1" height="1" fill="black" />
    <rect x="6" y="0" width="1" height="1" fill="black" />
    <rect x="8" y="0" width="1" height="1" fill="black" />
    <rect x="0" y="1" width="1" height="1" fill="black" />
    <rect x="2" y="1" width="1" height="1" fill="black" />
    <rect x="3" y="1" width="1" height="1" fill="black" />
    <rect x="4" y="1" width="1" height="1" fill="black" />
    <rect x="5" y="1" width="1" height="1" fill="black" …