51 lines
1.9 KiB
Ruby
51 lines
1.9 KiB
Ruby
module Vm
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# class that acts like a class, but is really the object
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# described in the ruby language book as the eigenclass, what you get with
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# class MyClass
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# class << self <--- this is called the eigenclass, or metaclass, and really is just the class object
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# .... but gives us the ability to use the syntax as if it were a class
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# PS: can't say i fancy the << self syntax and am considerernig adding a keyword for it, like meta
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# In effect it is a very similar construct to def self.function(...)
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# So one could write def meta.function(...) and thus define on the meta-class
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class MetaClass < ObjectConstant
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# no name, nor nothing. as this is just the object really
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def initialize(object)
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super()
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@functions = []
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@me_self = object
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end
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# in a non-booting version this should map to _add_singleton_method
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def add_function function
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raise "not a function #{function}" unless function.is_a? Function
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raise "syserr " unless function.name.is_a? Symbol
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@functions << function
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end
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def get_function name
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name = name.to_sym
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f = @functions.detect{ |f| f.name == name }
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puts "no function for :#{name} in Meta #{@me_self.inspect}" unless f
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f
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end
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# get the function and if not found, try superclasses. raise error if not found
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def resolve_function name
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fun = get_function name
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# TODO THE BOOK says is class A derives from B , then the metaclass of A derives from the metaclass of B
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# just get to it ! (and stop whimpering)
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raise "Method not found #{name} , for #{inspect}" unless fun
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fun
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end
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def inspect
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"MetaClass on #{@me_self}, #{@functions.length} functions"
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end
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def to_s
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inspect
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end
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end
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end
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