Class: MetaBuilder::Parameter

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/MetaBuilder/parameter.rb,
lib/MetaBuilder/Qt4/parameter.rb

Overview

A parameter describes a way of storing some information into an instance of an object. No type checking is done on the target object when the actual reading/writing is done. However, the type checking is done upstream by the Description system.

A Parameter consists of several things:

  • a #name, to identify it in a unique fashion;

  • a #type, used to convert to and from String and for user interaction in general;

  • some explanative text, used to inform the user: #long_name and #description

  • two symbols that are used to gain read and write access of the parameter on the target object.

The Parameter class can be used to maintain a set of meta-informations about types in a given object.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, writer_symbol, reader_symbol, long_name, type, description, attributes = {}) ⇒ Parameter

Creates a new Parameter with the given symbols. Remember that if you don’t intend to use #get, #get_raw, #set and #set_raw, you don’t need to pass meaningful values to writer_symbol and reader_symbol.



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# File 'lib/MetaBuilder/parameter.rb', line 307

def initialize(name, writer_symbol,
               reader_symbol,
               long_name, 
               type,
               description, attributes = {})
  @name = name
  @writer_symbol = writer_symbol
  @reader_symbol = reader_symbol
  @description = description
  @long_name = long_name
  @type_spec = type
  type_class = ParameterType.get_param_type(@type_spec)
  raise "Parameter type not recognized: #{@type_spec}" unless type_class
  
  @param_type = type_class.new(@type_spec)
  @attributes = attributes
end

Instance Attribute Details

#description ⇒ Object

The (text) description of the parameter



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# File 'lib/MetaBuilder/parameter.rb', line 282

def description
  @description
end

#long_name ⇒ Object

The long name of the parameter, to be translated



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# File 'lib/MetaBuilder/parameter.rb', line 274

def long_name
  @long_name
end

#name ⇒ Object

The short name of the parameter



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# File 'lib/MetaBuilder/parameter.rb', line 271

def name
  @name
end

#param_type ⇒ Object

The actual ParameterType subclass instance in charge of handling the conversion from string.



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# File 'lib/MetaBuilder/parameter.rb', line 289

def param_type
  @param_type
end

#reader_symbol ⇒ Object

The function names that should be used to set the symbol and retrieve it’s current value. The corresponding functions should read or return a string, and writer(reader) should be a noop.



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# File 'lib/MetaBuilder/parameter.rb', line 279

def reader_symbol
  @reader_symbol
end

#type_spec ⇒ Object

The way the type was specified to the system



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# File 'lib/MetaBuilder/parameter.rb', line 285

def type_spec
  @type_spec
end

#writer_symbol ⇒ Object

The function names that should be used to set the symbol and retrieve it’s current value. The corresponding functions should read or return a string, and writer(reader) should be a noop.



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# File 'lib/MetaBuilder/parameter.rb', line 279

def writer_symbol
  @writer_symbol
end

Instance Method Details

#get(target) ⇒ Object

Aquires the value from the backend, and returns it in the form of a string



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# File 'lib/MetaBuilder/parameter.rb', line 344

def get(target)
  return type_to_string(get_raw(target))
end

#get_raw(target) ⇒ Object

Aquires the value from the backend, and returns it.



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# File 'lib/MetaBuilder/parameter.rb', line 349

def get_raw(target)
  target.send(@reader_symbol)
end

#option_parser_option(parser, name, instance) ⇒ Object

Creates an option in the OptionParser parser, with the name name, that will change the settings of the object instance



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# File 'lib/MetaBuilder/parameter.rb', line 355

def option_parser_option(parser, name, instance)
  obj = instance # copy needed to avoid problems with
  # overwritten local variables
  block = proc do |value|
    set_raw(obj, value)
  end

  # The use of #attributes is already deprecated. Don't use !!!
#       if attributes.has_key?(:option_parser_short)
#         @param_type.option_parser_raw(parser, attributes[:option_parser_short],
#                                       @param_type.option_parser_long_option(name), 
#                                       description, &block) 
#       else
  @param_type.option_parser_option(parser, name, description, &block) 
#       end
end

#set(target, str) ⇒ Object

Uses the #writer_symbol of the target to set the value of the parameter to the one converted from the String str



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# File 'lib/MetaBuilder/parameter.rb', line 337

def set(target, str)
  set_raw(target, string_to_type(str)) 
end

#set_raw(target, val) ⇒ Object

Sets directly the target parameter, without type conversion



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# File 'lib/MetaBuilder/parameter.rb', line 331

def set_raw(target, val)
  target.send(@writer_symbol, val) 
end