Class: Taoism::Environment

Inherits:
Object
  • Object
show all
Defined in:
lib/taoism/environment.rb

Instance Method Summary collapse

Constructor Details

#initialize(outer = nil) ⇒ Environment

Returns a new instance of Environment.



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# File 'lib/taoism/environment.rb', line 3

def initialize(outer = nil)
  @outer = outer
  @scope = {}
end

Instance Method Details

#define(name, value, mutable:) ⇒ Object 



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# File 'lib/taoism/environment.rb', line 8

def define(name, value, mutable:)
  if @scope.key?(name)
    raise Runtime::Error, "already defined variable: #{name}"
  end

  @scope[name] = { value: value, mutable: mutable }
end

#get(name) ⇒ Object 



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# File 'lib/taoism/environment.rb', line 16

def get(name)
  if @scope.key?(name)
    @scope[name][:value]
  elsif @outer
    @outer.get(name)
  else
    raise Runtime::Error, "undefined variable: #{name}"
  end
end

#has?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/taoism/environment.rb', line 40

def has?(name)
  @scope.key?(name) or @outer&.has?(name)
end

#set(name, value) ⇒ Object 



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# File 'lib/taoism/environment.rb', line 26

def set(name, value)
  if @scope.key?(name)
    if @scope[name][:mutable]
      @scope[name][:value] = value
    else
      raise Runtime::Error, "cannot assign to immutable variable"
    end
  elsif @outer
    @outer.set(name, value)
  else
    raise Runtime::Error, "undefined variable: #{name}"
  end
end