Class: Babl::Utils::Value

Inherits:
Object
  • Object
show all
Defined in:
lib/babl/utils/value.rb

Overview

Construct deeply immutable value objects Similar to Struct, but:

  • Properties are assumed deeply immutable (#hash is assumed constant)

  • Constructor requires all arguments

  • #== has the same meaning as #eql?

Class Method Summary collapse

Class Method Details

.new(*fields) ⇒ Object 



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# File 'lib/babl/utils/value.rb', line 12

def self.new(*fields)
    ::Class.new(::Struct.new(:_cached_hash, *fields)) do
        field_aliases = ::Array.new(fields.size) { |i| "v#{i}" }
        const_set(:FIELDS, fields.map(&:to_sym))
        class_eval "            def initialize(\#{field_aliases.join(',')})\n                super(\#{['nil', field_aliases].join(',')})\n                hash\n                freeze\n            end\n\n            def hash\n                self._cached_hash ||= super\n            end\n\n            def ==(other)\n                eql?(other)\n            end\n\n            def self.with(hash = Utils::Hash::EMPTY)\n                raise ::ArgumentError unless ::Hash === hash && (hash.keys - FIELDS).empty?\n                new(*FIELDS.map { |f| hash.fetch(f) })\n            end\n        RUBY\n    end\nend\n"