Class: Roby::DelayedArgumentFromObject

Inherits:
Object
  • Object
show all
Extended by:
Roby::DRoby::V5::Builtins::ClassDumper
Includes:
Roby::DRoby::V5::DelayedArgumentFromObjectDumper
Defined in:
lib/roby/task_arguments.rb,
lib/roby/droby/enable.rb

Overview

Placeholder that can be used to assign an argument from an object’s attribute, reading the attribute only when the task is started

This will usually not be used directly. One should use Task.from instead

Direct Known Subclasses

DelayedArgumentFromState

Instance Method Summary collapse

Methods included from Roby::DRoby::V5::Builtins::ClassDumper

droby_dump

Methods included from Roby::DRoby::V5::DelayedArgumentFromObjectDumper

#droby_dump

Constructor Details

#initialize(object, weak = true) ⇒ DelayedArgumentFromObject

Returns a new instance of DelayedArgumentFromObject.



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# File 'lib/roby/task_arguments.rb', line 289

def initialize(object, weak = true)
    @object = object
    @methods = []
    @expected_class = Object
    @weak = weak
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(m, *args) ⇒ Object 



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# File 'lib/roby/task_arguments.rb', line 335

def method_missing(m, *args)
    if args.empty? && !block_given?
        @methods << m
        self
    else
        super
    end
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/roby/task_arguments.rb', line 344

def ==(other)
    other.kind_of?(DelayedArgumentFromObject) &&
        @object.object_id == other.instance_variable_get(:@object).object_id &&
        @methods == other.instance_variable_get(:@methods)
end

#evaluate_delayed_argument(task) ⇒ Object 



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# File 'lib/roby/task_arguments.rb', line 301

def evaluate_delayed_argument(task)
    result = @methods.inject(@object || task) do |v, m|
        if v.kind_of?(Roby::Task) && v.model.has_argument?(m)
            # We are trying to access a task argument, throw no_value if the
            # argument is not set
            if !v.arguments.has_key?(m)
                throw :no_value
            end

            argument = v.arguments.values[m]
            if TaskArguments.delayed_argument?(argument)
                argument.evaluate_delayed_argument(v)
            else
                argument
            end
        elsif v.respond_to?(m)
            begin v.send(m)
            rescue Exception
                throw :no_value
            end
        elsif @weak
            throw :no_value
        else
            task.failed_to_start!("#{v} has no method called #{m}")
            throw :no_value
        end
    end

    if @expected_class && !result.kind_of?(@expected_class)
        throw :no_value
    end
    result
end

#of_type(expected_class) ⇒ Object 



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# File 'lib/roby/task_arguments.rb', line 296

def of_type(expected_class)
    @expected_class = expected_class
    self
end

#pretty_print(pp) ⇒ Object 



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# File 'lib/roby/task_arguments.rb', line 354

def pretty_print(pp)
    pp.text to_s
end

#to_s ⇒ Object 



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# File 'lib/roby/task_arguments.rb', line 350

def to_s
    "delayed_argument_from(#{@object || 'task'}.#{@methods.map(&:to_s).join(".")})"
end