Command

[silverweed]

Addresses #4. Many ideas were taken from https://github.com/golang/go/blob/master/src/cmd/go.

What I changed

Basically I slightly changed the way that wapty subcommands are organized. Now every package that exports a standalone main must declare a *common.Command variable which contains the information needed to run it, the flags it accepts (if any) and the usage description.

More specifically, these packages should have a init.go file containing:

1. the Command exported variable, like:

package decode
var CmdDecode = &common.Command{
    // ...
}

2. optionally, the init() function of that package. I suggest this be in the same file as the exported Command variable as it can be used to initialize the command flagset if needed (see decode/init.go for an example).

The wapty main entrypoint was changed to adapt to these changes, but the logic remains the same.
Note that the proxy and the version commands were also changed to adapt to this interface.

What I added

I added a common package, containing the definition of a Command plus a convenient FindCommand function which contains the logic that was previously in invokeMain. I factored this logic out since the new help package needed the same exact thing. The new function returns an error instead of setting a success bool variable.

I also added a help package which exports a help command that just prints the detailed information about a subcommand (which is different from the -h of that command).

How the flags work now

As I mentioned, every Command contains its flagset, whose parsing is now completely done by the invokeMain function. This is convenient as it eliminates repeated flag parsing logic in every command's entrypoint.
So, if your command needs some custom flags, do this:

1. in the file containing your command's entrypoint, declare your flag variables (e.g. flagMyBool);
2. create an init.go file for your package and define your Command atop of it;
3. in the init function call CmdMyCommand.Flag.BoolVar(&flagMyBool, "false", "blah", "blah");
4. when your main will be called, the flags will be ready for use, so just use them normally.

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Ideas/critiques/suggestions are welcome :-)

[silverweed]

By the way, I couldn't really test if this change broke something in decode as I don't know how it works, so please review that part very carefully :D