`class Resource`

A Resource represents a fixed amount of a named currency or material.

Definitions

`def self.parse(string, default_name: nil)`

Parse a string representation of a resource.

Signature

parameter　string　String: e.g "5 NZD".
returns　Resource: The Resource that represents the parsed string.

Implementation

def self.parse(string, default_name: nil)
	amount, name = string.split(/\s+/, 2)
	
	self.new(amount, name || default_name)
end

`def self.load(input)`

Load a string representation of a resource.

Signature

parameter　string　String | Nil: e.g. "5 NZD" or nil.
returns　Resource | Nil: The Resource that represents the parsed string.

Implementation

def self.load(input)
	if input.is_a?(String)
		input = input.strip
		return parse(input) unless input.empty?
	end
end

`def self.dump(resource)`

Dump a string representation of a resource.

Signature

parameter　resource　Resource: The resource to dump.
returns　String | Nil: A string that represents the class Latinum::Resource.

Implementation

def self.dump(resource)
	resource.to_s if resource
end

`attr :amount`

The amount of the resource.

Signature

attribute　BigDecimal

`attr :name`

The name of the resource.

Signature

attribute　String

`def + other`

Add two resources. Must have the same name.

Signature

returns　Resource: A resource with the added amount.

Implementation

def + other
	raise DifferentResourceNameError if @name != other.name
	
	self.class.new(@amount + other.amount, @name)
end

`def - other`

Subtract two resources. Must have the same name.

Signature

returns　Resource: A resource with the subtracted amount.

Implementation

def - other
	raise DifferentResourceNameError if @name != other.name
	
	self.class.new(@amount - other.amount, @name)
end

`def -@`

Invert the amount of the resource.

Signature

returns　Resource: A resource with the negated amount.

Implementation

def -@
	self.class.new(-@amount, @name)
end

`def * factor`

Multiplies the resource by a given factor.

Signature

returns　Resource: A resource with the updated amount.

Implementation

def * factor
	self.class.new(@amount * factor, @name)
end

`def / factor`

Divides the resource by a given factor.

Signature

returns　Resource: A resource with the updated amount.

Implementation

def / factor
	if factor.is_a? self.class
		raise DifferentResourceNameError if @name != factor.name
		
		@amount / factor.amount
	else
		self.class.new(@amount / factor, @name)
	end
end

`def exchange(rate, name, precision = nil)`

Compute a new resource using the given exchange rate for the specified name.

Signature

parameter　rate　Numeric: The exchange rate to use.
parameter　name　String: The name of the new resource.
parameter　precision　Integer | Nil: The number of decimal places to round to.

Implementation

def exchange(rate, name, precision = nil)
	return self if @name == name
	
	exchanged_amount = @amount * rate
	
	exchanged_amount = exchanged_amount.round(precision) if precision
	
	self.class.new(exchanged_amount, name)
end

`def to_s`

A human readable string representation of the resource amount and name.

Signature

returns　String: e.g. "5 NZD".

Implementation

def to_s
	"#{@amount.to_s('F')} #{@name}"
end

`def to_digits`

A human readable string representation of the resource amount.

Signature

returns　String: e.g. "5.00".

Implementation

def to_digits
	@amount.to_s('F')
end

`def <=> other`

Compare with another class Latinum::Resource or a Numeric value.

Implementation

def <=> other
	if other.is_a? self.class
		result = @amount <=> other.amount
		return result unless result == 0
		
		result = @name <=> other.name
		return result
	elsif other.is_a? Numeric
		@amount <=> other
	end
end

`def zero?`

Whether the amount of the resource is zero.

Signature

returns　Boolean

Implementation

def zero?
	@amount.zero?
end