您如何在多行代码中链接命令? [英] how do you chain commands on several lines in go?

问题描述

我想通过这种方式链接命令:

I want to chain commands this way :

var cmdGroups = []*commands.CmdGroup {
    commands.MakeCmdGroup("foo", cmd1, cmd2, cmd3).AddConstraint(cmd1, cmd2).AddConstraint(cmd2, cmd1, cmd3),
    commands.MakeCmdGroup("bar", cmd1, cmd4).AddConstraint(cmd1, cmd4),
}

出于80列长度的原因，我想将链分成几行，但是Go不允许我编译它:

I'd like to split my chains on several lines for 80-column-lengths reasons, but Go won't let me compile this :

var cmdGroups = []*commands.CmdGroup {
    commands.MakeCmdGroup("foo", cmd1, cmd2, cmd3)
            .AddConstraint(cmd1, cmd2)
            .AddConstraint(cmd2, cmd1, cmd3),
    commands.MakeCmdGroup("bar", cmd1, cmd4)
            .AddConstraint(cmd1, cmd4),
}

我该怎么办?

推荐答案

正如FUZxxl指出的那样，您的问题是分号的自动插入.规范说:

As FUZxxl pointed out, your problem is the automatic insertion of semicolons. The spec says:

当输入被分解为标记时，将自动使用分号如果非空白行的末尾插入到令牌流中，该行的最终令牌是

When the input is broken into tokens, a semicolon is automatically inserted into the token stream at the end of a non-blank line if the line's final token is

• 标识符
• 整数，浮点数，虚数，符文或字符串文字
• 其中一个关键字会中断，继续，失败或返回
• 运算符和定界符++，-，)，]或}

您有一个函数调用，该函数计数为)，因此在行的末尾添加了分号.

You have a function call, which counts for a ) so a semicolon is added at the end of the line.

要避免自动分号转换，您可以使用以下任一方式编写呼叫方式:

To circumvent automatic semicolon conversion you can write your calls in one of the following ways:

使用.代替分号:

x.
Method(p1,p2,p3)

在参数列表开头而不是函数之前中断:

Break after beginning of parameter list instead of before the function:

x.Method(
   p1,p2,p3, // , at the end is important to prevent semicolon insertion
)

如果您不喜欢上述方法，则可以(从go1.1开始)将这些方法视为第一类市民并临时创建可能更短的快捷方式:

If you dislike the methods above, you can (as of go1.1) treat the methods as first class citizens and temporarily create shortcuts which might be shorter:

f = x.Method
f(p1,p2,p3).f(p3,p4,p5)

我还没想好这个例子.当然不可能使用 f(...).f(...)，因为 f 的返回值没有成员 f .必须重新分配 f .这样您一无所获.

I haven't thought enough with this example. f(...).f(...) is of course not possible, as the return value of f has no member f. One would have to reassign f. So you gain nothing from that.

这篇关于您如何在多行代码中链接命令?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！