class ActiveModel::Type::Decimal
Active Model
Decimal Type¶ ↑
Attribute
type for decimal, high-precision floating point numeric representation. It is registered under the :decimal
key.
class BagOfCoffee include ActiveModel::Attributes attribute :weight, :decimal end
Numeric instances are converted to BigDecimal instances. Any other objects are cast using their to_d
method, except for blank strings, which are cast to nil
. If a to_d
method is not defined, the object is converted to a string using to_s
, which is then cast using to_d
.
bag = BagOfCoffee.new bag.weight = 0.01 bag.weight # => 0.1e-1 bag.weight = "0.01" bag.weight # => 0.1e-1 bag.weight = "" bag.weight # => nil bag.weight = :arbitrary bag.weight # => nil (the result of `.to_s.to_d`)
Decimal
precision defaults to 18, and can be customized when declaring an attribute:
class BagOfCoffee include ActiveModel::Attributes attribute :weight, :decimal, precision: 24 end
Constants
- BIGDECIMAL_PRECISION
Public Instance Methods
Source
# File lib/active_model/type/decimal.rb, line 53 def type_cast_for_schema(value) value.to_s.inspect end
Private Instance Methods
Source
# File lib/active_model/type/decimal.rb, line 98 def apply_scale(value) if scale value.round(scale) else value end end
Source
# File lib/active_model/type/decimal.rb, line 58 def cast_value(value) casted_value = \ case value when ::Float convert_float_to_big_decimal(value) when ::Numeric BigDecimal(value, precision || BIGDECIMAL_PRECISION) when ::String begin value.to_d rescue ArgumentError BigDecimal(0) end else if value.respond_to?(:to_d) value.to_d else cast_value(value.to_s) end end apply_scale(casted_value) end
Source
# File lib/active_model/type/decimal.rb, line 82 def convert_float_to_big_decimal(value) if precision BigDecimal(apply_scale(value), float_precision) else value.to_d end end
Source
# File lib/active_model/type/decimal.rb, line 90 def float_precision if precision.to_i > ::Float::DIG + 1 ::Float::DIG + 1 else precision.to_i end end