Cannot see switches default value

[Tereci]

Hi, I have a problem - maybe it is just my misunderstanding of how to use gli - that inside of c.action I cannot see any value for commands switch even if I set a default one. I use version 1.6.0.

I generated the stub using "gli init project_name commands" and I added a switch like:

desc ''
arg_name 'Describe arguments to synchronize_datasets here'
command :synchronize_datasets do |c|
c.desc 'Model directory'
c.default_value '.'
c.flag [:m, :model_dir]

c.desc ''
c.default_value true
c.switch [:e, :execute]

c.action do |global_options,options,args|
pp options
end
end

and I get only {:m=>".", :model_dir=>"."} . Is it not possible to set a default value to a switch?
Thank you - didnt know where else to ask.
T.

[Tereci]

One more thing I found out - I also use argv and if I call the command with no arguments, the switch get initialized properly... But if I call the command with an argument (utils synchronize_datasets file.xml) I got what I described above.

[davetron5000]

Switches are just true or false, and the default value is currently assumed to be false. In GLI 1.x there is no way to specify a switch as false on the command line, so if the switch were defaulted to true, the user could never turn it "off".

This is somewhat rectified in GLI 2 (which is not yet available via RubyGems)

For your case, you can get around this like so:

c.desc "Don't actually execute anything"
c.switch [:n,:'dry-run']

Basically reversing the meaning of the switch. Now, you would do something like:

do_execute unless options['dry-run']

Also, you should not use ARGV in a GLI app; GLI will modify ARGV when it parses, and the value of args to your c.action block will be whatever was left in ARGV after parsing the command-line options and command-name

[bdiz]

I'm using GLI 2. What are you referring to wrt this issue being "rectified"? default_value still seems to work only for flags. Switches work great for turning things on, but if you want to default to on and have a switch to turn something off.. I can't seem to figure it out.

[davetron5000]

I guess what I'm saying is that switches only ever have a default value of false. You cannot set their default value to true via the DSL.

If you want a switch that defaults to on, you can handle it directly like so:

desc 'execute for real (defaults true)'
switch 'execute', :negatable => true

pre do |global_options,options,args|
  global_options[:execute] = true if global_options[:execute].nil?
end

command :foo do |c|
  c.action do |global_options,options,args|
    if global_options[:execute] # will be true if the user omitted it on the command line
  end
end

I agree that's a bit of a kludge, but it's pretty unusual (at least in my experience) to have a switch that, if omitted, defaults to true. Usually a switch is used to switch something on that is off by default, and the negatable form is to allow overriding a switch that was set "on" in a config file or environment variable.

[bdiz]

I have a switch which removes borders from the table it prints. By default borders are on. I can try using the pre hook. Would be nice to have a default_value for wierdos like me. Thanks.

-----Original Message-----
From: David Copeland [mailto:reply@reply.github.com]
Sent: Monday, July 09, 2012 7:12 AM
To: Delsol, Ben
Subject: Re: [gli] Cannot see switches default value (#86)

I guess what I'm saying is that switches only ever have a default value of false. You cannot set their default value to true via the DSL.

If you want a switch that defaults to on, you can handle it directly like so:

desc 'execute for real (defaults true)'
switch 'execute', :negatable => true

pre do |global_options,options,args|
  global_options[:execute] = true if global_options[:execute].nil?
end

command :foo do |c|
  c.action do |global_options,options,args|
    if global_options[:execute] # will be true if the user omitted it on the command line
  end
end

I agree that's a bit of a kludge, but it's pretty unusual (at least in my experience) to have a switch that, if omitted, defaults to true. Usually a switch is used to switch something on that is off by default, and the negatable form is to allow overriding a switch that was set "on" in a config file or environment variable.

---

Reply to this email directly or view it on GitHub:
#86 (comment)

[bdiz]

I've noticed that the pre hook trick works for global options, but for sub-command switches, the switch value is always false. I've had to look into ARGV myself to see if the sub-command switch is present.

[pdf]

Can we re-open this to get default_value working for switches?

[davetron5000]

I'm fine re-opening it, but I do feel like having a switch default to true would be a very confusing user experience. That said, it's probably not too much effort to implement…

[davetron5000]

Should be in 2.5.0

[davetron5000]

Also, be mindful that you don't make a switch that defaults to true, but is not negatable - GLI will fail with an error in that case