Class: Dhall::TypeChecker::Merge::Handlers

Inherits:
Object
  • Object
show all
Defined in:
lib/dhall/typecheck.rb

Instance Method Summary collapse

Constructor Details

#initialize(annotation) ⇒ Handlers

Returns a new instance of Handlers.



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# File 'lib/dhall/typecheck.rb', line 732

def initialize(annotation)
	@type = annotation.type

	TypeChecker.assert @type, Dhall::RecordType,
	                   "Merge expected Record got: #{@type}"
end

Instance Method Details

#fetch_input_type(k) ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 755

def fetch_input_type(k)
	type = @type.record.fetch(k) do
		raise TypeError, "No merge handler for alternative: #{k}"
	end

	TypeChecker.assert type, Dhall::Forall, "Handler is not a function"

	type.type
end

#keys ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 751

def keys
	@type.record.keys
end

#output_type(output_annotation = nil) ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 739

def output_type(output_annotation=nil)
	@type.record.values.reduce(output_annotation) do |type_acc, htype|
		htype = htype.body.shift(-1, htype.var, 0) if htype.is_a?(Dhall::Forall)

		if type_acc && htype.normalize != type_acc.normalize
			raise TypeError, "Handler output types must all match"
		end

		htype
	end
end