Help using optionparser

Ruby
1

Hi,

I wanted to take cmd line inputs of the form

File.rb -p A
File.rb -p B STRING
File.rb -p C STRING

Im using optionparser to parse the arguments.

I can create an arg and force it to accept inputs of A/B/C but how do i
ensure the extra arg is accepted only when its B/C?

opts.on("-p [STRING]", [:A,:B,:C], “”) do |v|
options[:p] = v
end

2

The non-flag command line arguments are left in ARGV after
OptionParser runs. So you would do something like

if options[:p] == ‘B’ or options[:p] == ‘C’
if ARGV.length != 0
raise ‘unexpected argument’
else
do_stuff ARGV[0]
end
end

– Matma R.

3

On Jun 15, 2012, at 6:11 PM, “cyber c.” [email protected] wrote:

opts.on(“-p [STRING]”, [:A,:B,:C], “”) do |v|
options[:p] = v
end

If it is positional, use Array instead of fixed values and check
manually:

opts.on “-p [STRING]”, Array do |ary|
raise OptionParser::InvalidArgument, “‘A’ cannot be followed by other
values”

…

end

File.rb -p A,String # fails
File.rb -p B,String

If you use this type of input multiple times you can create a validator
you can reuse, too

4

On Sat, Jun 16, 2012 at 11:32 AM, Bartosz Dziewoński
[email protected] wrote:

The non-flag command line arguments are left in ARGV after
OptionParser runs. So you would do something like

if options[:p] == ‘B’ or options[:p] == ‘C’
if ARGV.length != 0
raise ‘unexpected argument’
else
do_stuff ARGV[0]
end
end

Yes. Note that one has to use OptionParser#parse! in order to have it
remove options from the command line. I usually do

OptionParser.new do |opts|
opts.on …
end.parse! ARGV

Kind regards

robert

5

Thank you all for the suggestions :slight_smile: