module BanditMask::Banditry
Public Instance Methods
bandit_mask(attribute, as:, with: BanditMask)
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Creates wrapper methods for reading, writing, and querying the bitmask stored in attribute
using the class with
. with
defaults to BanditMask
, but you can (and probably should) define your own class inheriting from BanditMask
to fill this role. The name of the accessor methods will be derived from as
, e.g., if as
is :foo
, the methods will be named :foo
, :foo=
, and :foo?
.
The reader method will return a BanditMask
representation of attribute
.
The writer method overwrites the current bitmask if with an Array of bits, or it updates the current bitmask if sent an individual bit, e.g., using +#|+.
In addition to the accessor methods, a query method that delegates to BanditMask#include?
will be added.
class FileMask < BanditMask bit :r, 0b001 bit :w, 0b010 bit :e, 0b100 end class FileObject attr_accessor :mode_mask extend BanditMask::Banditry bandit_mask :mode_mask, as: :mode, with: FileMask end file = FileObject.new file.mode_mask # => nil file.mode |= :r file.mode_mask # => 1 file.mode |= :w file.mode_mask # => 3 file.mode = [:r, :x] file.mode_mask # => 5
# File lib/banditmask/banditry.rb, line 44 def bandit_mask(attribute, as:, with: BanditMask) class_eval do generate_reader attribute, as, with generate_writer attribute, as, with generate_query attribute, as, with end end
Private Instance Methods
generate_query(attr, virt, cls)
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# File lib/banditmask/banditry.rb, line 80 def generate_query(attr, virt, cls) respond_to? :"#{virt}?" and raise MethodCollisionError, "method `#{virt}?` already exists" define_method :"#{virt}?" do |*bits| cls.new(send(attr)).include? *bits end end
generate_reader(attr, virt, cls)
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# File lib/banditmask/banditry.rb, line 54 def generate_reader(attr, virt, cls) respond_to? virt and raise MethodCollisionError, "method `#{virt}` already exists" define_method virt do instance_variable_get(:"@#{virt}") || instance_variable_set(:"@#{virt}", cls.new(send(attr))) end end
generate_writer(attr, virt, cls)
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# File lib/banditmask/banditry.rb, line 64 def generate_writer(attr, virt, cls) respond_to? :"#{virt}=" and raise MethodCollisionError, "method `#{virt}=` already exists" define_method :"#{virt}=" do |bits| mask = case bits when BanditMask bits else bits.inject(cls.new) { |bm, bit| bm << bit } end send :"#{attr}=", Integer(mask) instance_variable_set :"@#{virt}", mask end end