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.



772
773
774
775
776
777
 
# File 'lib/dhall/typecheck.rb', line 772

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 



795
796
797
798
799
800
801
802
803
 
# File 'lib/dhall/typecheck.rb', line 795

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 



791
792
793
 
# File 'lib/dhall/typecheck.rb', line 791

def keys
	Set.new(@type.record.keys)
end

#output_type(output_annotation = nil) ⇒ Object 



779
780
781
782
783
784
785
786
787
788
789
 
# File 'lib/dhall/typecheck.rb', line 779

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