[Gambas-user] New component: gb.args

[Benoît Minisini]

Le 19/10/2012 12:19, Bruce a écrit :
> On Tue, 2012-10-16 at 02:06 +0200, Benoît Minisini wrote:
>> Hi,
>>
>> In the last revision, I added a new component 'gb.args', which replaces
>> the unmaintained 'gb.option'. By the way, does anyone use 'gb.option'?
>>
>> The goal of this component made in Gambas is analyzing the command-line
>> arguments and return the value of options.
>>
>> It works like that:
>>
>> ' Start the analyze : UsageString is an optional string describing
>> ' the global syntax of the command with its name.
>>
>> Args.Begin(UsageString)
>>
>> ' This method returns if an option is present or not, with the form
>> ' "-s" or "--long"
>>
>> Args.Has("s", "long", ("description"))
>>
>> ' This method defines an option that takes one string argument, and
>> ' returns it.
>>
>> Args.Get("s", "long", ("description"), ("argument name"))
>>
>> ' This method defines an option that takes one integer argument, and
>> ' returns it. The argument can be prefixed by "0x" for an hexadecimal
>> ' number.
>>
>> Args.GetInteger("s", "long", ("description"), ("argument name"),
>>     DefaultValue)
>>
>> ' This method ends the analyze, and returns all extra arguments (that
>> ' usually are file paths to process). The arguments are returned into
>> ' a String array.
>>
>> Args.End()
>>
>> Moreover, the End() method automatically handles:
>>
>> - An '-h/--help' option that prints the program usage by using the usage
>> string sent to the Begin() function and all option descriptions.
>>
>> - A '-V/--version' option that prints the program version.
>>
>> Tell me what you think about that component!
>>
>> Regards,
>>
> Hi Benoît,
>
> I've given this (gb.args) a bit of a try and I quite like it.  One
> question arose though.
>
> We have some components and libraries that search Application.Args for
> an occurrence of a command line arg.  For example one component, our
> central db connection manager looks for a "--reconfiguredb" CL option
> that allows/forces the user to re-enter the database connection
> parameters when we have released a new version of the database.  (So if
> we move from auctions030108 to auctions030109 on our central database,
> we let them know that they have to run our main app with the
> --reconfiguredb option.)
>
> Here's the question.  It would be nice, or to put it another way, is it
> possible to declare the Args.Has("","--reconfiguredb", "Reset the
> central database connection") in the component or do we have to do it in
> any/all the apps that use that component?
>
> regards
> Bruce
>

Mmm... The current syntax prevents that, because everything is done 
between Args.Begin() and Args.End().

Note that you must just collect the result of Args.Has() and Args.Get() 
before calling Args.End(). All processing must be done after!

You can:

- Call Args.Has("", "--reconfiguredb") in all projects explicitely.

- Or call it after testing that a specific component is used, with 
Component.IsLoaded()

- Or override Args in the component, reimplement Args.End() to add the 
Args.Has("", ""--reconfiguredb")

The last solution needs no change in the projects. Only in the components.

Regards,

-- 
Benoît Minisini