Class: Slop::Option

Inherits:
Object
  • Object
show all
Defined in:
lib/slop/option.rb

Constant Summary collapse

DEFAULT_CONFIG = 
{
  help: true,
  tail: false,
  underscore_flags: true,
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(flags, desc, **config, &block) ⇒ Option

Returns a new instance of Option.



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# File 'lib/slop/option.rb', line 29

def initialize(flags, desc, **config, &block)
  @flags  = flags
  @desc   = desc
  @config = DEFAULT_CONFIG.merge(config)
  @block  = block
  reset
end

Instance Attribute Details

#block ⇒ Object (readonly)

A custom proc that yields the option value when it's executed.



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# File 'lib/slop/option.rb', line 24

def block
  @block
end

#config ⇒ Object (readonly)

A Hash of configuration options.



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# File 'lib/slop/option.rb', line 16

def config
  @config
end

#count ⇒ Object (readonly)

An Integer count for the total times this option has been executed.



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# File 'lib/slop/option.rb', line 20

def count
  @count
end

#desc ⇒ Object (readonly)

A custom description used for the help text.



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# File 'lib/slop/option.rb', line 13

def desc
  @desc
end

#flags ⇒ Object (readonly)

An Array of flags this option matches.



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# File 'lib/slop/option.rb', line 10

def flags
  @flags
end

#value ⇒ Object

Returns the value for this option. Falls back to the default (or nil).



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# File 'lib/slop/option.rb', line 90

def value
  @value || default_value
end

Instance Method Details

#call(_value) ⇒ Object

This method is called immediately when an option is found. Override it in sub-classes.

Raises:



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# File 'lib/slop/option.rb', line 66

def call(_value)
  raise NotImplementedError,
    "you must override the `call' method for option #{self.class}"
end

#default_value ⇒ Object

Returns the default value for this option (default is nil).



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# File 'lib/slop/option.rb', line 95

def default_value
  config[:default]
end

#ensure_call(value) ⇒ Object

Since call() can be used/overriden in subclasses, this method is used to do general tasks like increment count. This ensures you don't have to call super when overriding call(). It's used in the Parser.



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# File 'lib/slop/option.rb', line 48

def ensure_call(value)
  @count += 1

  if value.nil? && expects_argument?
    if default_value
      @value = default_value
    elsif !suppress_errors?
      raise Slop::MissingArgument.new("missing argument for #{flag}", flags)
    end
  else
    @value = call(value)
  end

  block.call(@value) if block.respond_to?(:call)
end

#expects_argument? ⇒ Boolean

Override this if this option type does not expect an argument (i.e a boolean option type).

Returns:

  • (Boolean) 


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# File 'lib/slop/option.rb', line 79

def expects_argument?
  true
end

#finish(_result) ⇒ Object

By default this method does nothing. It's called when all options have been parsed and allows you to mutate the @value attribute according to other options.



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# File 'lib/slop/option.rb', line 74

def finish(_result)
end

#flag ⇒ Object

Returns all flags joined by a comma. Used by the help string.



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# File 'lib/slop/option.rb', line 105

def flag
  flags.join(", ")
end

#help? ⇒ Boolean

Returns true if this option should be displayed in help text.

Returns:

  • (Boolean) 


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# File 'lib/slop/option.rb', line 122

def help?
  config[:help]
end

#key ⇒ Object

Returns the last key as a symbol. Used in Options.to_hash.



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# File 'lib/slop/option.rb', line 110

def key
  key = config[:key] || flags.last.sub(/\A--?/, '')
  key = key.tr '-', '_' if underscore_flags?
  key.to_sym
end

#null? ⇒ Boolean

Override this if you want to ignore the return value for an option (i.e so Result#to_hash does not include it).

Returns:

  • (Boolean) 


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# File 'lib/slop/option.rb', line 85

def null?
  false
end

#reset ⇒ Object

Reset the option count and value. Used when calling .reset on the Parser.



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# File 'lib/slop/option.rb', line 39

def reset
  @value = nil
  @count = 0
end

#suppress_errors? ⇒ Boolean

Returns true if we should ignore errors that cause exceptions to be raised.

Returns:

  • (Boolean) 


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# File 'lib/slop/option.rb', line 100

def suppress_errors?
  config[:suppress_errors]
end

#tail ⇒ Object

Returns 1 if this option should be added to the tail of the help text. Used for sorting.



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# File 'lib/slop/option.rb', line 133

def tail
  tail? ? 1 : -1
end

#tail? ⇒ Boolean

Returns true if this option should be added to the tail of the help text.

Returns:

  • (Boolean) 


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# File 'lib/slop/option.rb', line 127

def tail?
  config[:tail]
end

#to_s(offset: 0) ⇒ Object

Returns the help text for this option (flags and description).



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# File 'lib/slop/option.rb', line 138

def to_s(offset: 0)
  "%-#{offset}s  %s" % [flag, desc]
end

#underscore_flags? ⇒ Boolean

Returns true if this option should be displayed with dashes transformed into underscores.

Returns:

  • (Boolean) 


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# File 'lib/slop/option.rb', line 117

def underscore_flags?
  config[:underscore_flags]
end