实现args功能

[guonaihong]

在shell里面，没有被当成命令行选项的参数，一般另有用途，clop提供args tag，用于保存下面的r.go pool.c会存放至cat.Args变量里。

cat -n r.go -T pool.c

clop用法

 type cat struct {
        NumberNonblank bool `clop:"-b;--number-nonblank"
                            usage:"number nonempty output lines, overrides"`

        ShowEnds bool `clop:"-E;--show-ends"
                            usage:"display $ at end of each line"`

        Number bool `clop:"-n;--number"
                            usage:"number all output lines"`

        SqueezeBlank bool `clop:"-s;--squeeze-blank"
                            usage:"suppress repeated empty output lines"`

        ShowTab bool `clop:"-T;--show-tabs"
                            usage:"display TAB characters as ^I"`

        ShowNonprinting bool `clop:"-v;--show-nonprinting"
                            usage:"use ^ and M- notation, except for LFD and TAB" `

        Args []string `clop:"args"`
    }   

c := cat{}
clop.Bind(&c)