Class: Optser::OptSet

Inherits:
Object
  • Object
show all
Defined in:
lib/optser/opt_set.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ OptSet

Returns a new instance of OptSet.



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# File 'lib/optser/opt_set.rb', line 8

def initialize(options)
  @options = Hashie::Mash.new options
end

Instance Attribute Details

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/optser/opt_set.rb', line 6

def options
  @options
end

Instance Method Details

#get(key, default = nil, &block) ⇒ Object

Lookup an option from our options set.

Examples:

# Optional parameter whose default value is nil.
do_extra = opt_set.get :do_extra

# Optional params that defaults to [1,2,3]
start_array = opt_set.get :start_array, [1,2,3]

Returns default value when:

  • Key is non-existent in Options Hash.

  • OR when the value of the key in the Options Hash is nil.

Returns nil when:

  • Default is nil and the Options Hash lookup returns a nil. Options Hash returns a nil because of either a non-existent key or a nil value in said hash for said key.



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# File 'lib/optser/opt_set.rb', line 32

def get(key, default=nil, &block)
  value = options[key]
  value = default if value.nil?
  value = block.call if value.nil? && block
  return value
end

#get!(key, default = nil, &block) ⇒ Object

Use this the option is mandatory.

There are cases where an option may have a default value for a feature, but the caller may just want to disable said feature. To do so, users of this module should allow for the caller to pass in ‘false’ as an option value instead of nil to disable said feature. The implementer will have to do a boolean check of the returned option value and disable accordingly.

Examples:

# Has a default logger, but we can disable logging by passing false.
# If caller had passed in nil for :logger, it would have
# defaulted to ::Log4r['my_logger'].
logger = opt_set.get! :logger, ::Log4r['my_logger']

# Here we force the end user to pass in a Non-nil option as a
# mandatory parameter.
max_threads = opt_set.get! :max_threads

Raises error when ‘get` returns a nil.



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# File 'lib/optser/opt_set.rb', line 62

def get!(key, default=nil, &block)
  value = get key, default, &block
  raise "Nil value found for option: #{key}, #{default}" if value.nil?
  return value
end