Re: [CLI] Switches ?

[John Keyes]

Sounds like a nice plan.  I forgot about switches as well, thanks for
the heads up Herve.
-John K

On Wednesday, Jul 2, 2003, at 16:26 Europe/Dublin, Rob Oxspring wrote:

Hi Herve,

Cheers for the pointer, I'd forgotten about switches.

I figured I'd use this opportunity to plug my own CLI2 proposal a 
little more so here's how I see switches slotting in:

A SwitchBuilder would be created to deal with a specific pair of 
enable / disable prefixes:
    SwitchBuilder sBuilder = new SwitchBuilder("+","-");

Then a SwitchOption would be created with a particular name:
    SwitchOption scrollbar = sBuilder.withName("sb").create();
The getPrefixes() for SwitchOption would return [+sb,-sb] and the 
CommandLine object would probably gain a method along the
following lines; returning TRUE iff the enabled version was present, 
FALSE iff the disabled version was present or null otherwise:
    Boolean getSwitch(SwitchOption)
(And an associated setSwitch(SwitchOption,Boolean) method)

Separating the prefixes allows us to use the same code to handle 
./configure style options such as "--enable-FEATURE" and
"--disable-FEATURE" simply by supplying "--enable" and "--disable" 
instead of "+" and "-".

If we make the SwitchOption extend ParentOption then we can even 
compose one with an Argument as follows:

    // build the switch
    SwitchOption sslSwitch = new 
SwitchBuilder("--with-","--without-").withName("ssl").create();

    // wrap in an argument
    Argument sslArgument = new 
ArgumentBuilder().withName("DIR").withChild(sslSwitch).create();

    ...

    // deal with ssl
    if(commandLine.getOption("--with-ssl")==Boolean.TRUE){
        sslDir = findSsl(commandLine.getValues("--with-ssl"));
    }
Thus the complex ./configure style options such as 
"--with-ssl=/usr/share/ssl" / "--without-ssl" would be supported out 
of the box.
The implementation should be pretty straight forward - new classes 
SwitchOption & SwitchBuilder, some addition to CommandLine and
lots of tests.  IMO, minimal impact for a handy new feature.

Rob

----- Original Message -----
From: "Herve Quiroz" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, July 01, 2003 3:19 PM
Subject: [CLI] Switches ?

Hi,

As you are still in design stage for CLI 2.0, I thought I might just
submit another feature that is used by command line parsers for some 
apps:
switches.

In CLI, the PREFIX for a command-line option is '-' but may be 
overriden
to become anything else.  Some apps have several different prefixes to
manage switches. When you consider xterm for example, you get two 
flavors
for the same option, one that "enable" it (with -option) and one that
"disable" it (with +option). For instance,

 '-sb' means you want the scrollbar
 '+sb' means you don't want it
Personally, I wouldn't use such a scheme to parse command line 
arguments
so I won't need it in a future version of CLI (BTW I find the next 
version
quite interesting). Thus, I am not requesting a new feature from CLI 
here.
Anyway, you might want to decide now if you plan to support such a 
feature
in the near future now that you are defining the API...

Regards,

Herve

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