Class: Dhall::TypeChecker::Merge::AnnotatedMerge

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

Instance Method Summary collapse

Constructor Details

#initialize(merge:, record:, input:) ⇒ AnnotatedMerge

Returns a new instance of AnnotatedMerge.



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# File 'lib/dhall/typecheck.rb', line 807

def initialize(merge:, record:, input:)
	@merge = merge.with(record: record, input: input)
	@handlers = Handlers.new(record)
	@record = record
	@union = input

	TypeChecker.assert @union.type, Dhall::UnionType,
	                   "Merge expected Union got: #{@union.type}"

	assert_union_and_handlers_match
end

Instance Method Details

#annotation ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 819

def annotation
	Dhall::TypeAnnotation.new(
		value: @merge,
		type:  type
	)
end

#assert_kind(context) ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 830

def assert_kind(context)
	kind = TypeChecker.for(type).annotate(context).type

	TypeChecker.assert(
		kind,
		Builtins[:Type],
		"Merge must have kind Type"
	)

	kind
end

#assert_union_and_handlers_match ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 842

def assert_union_and_handlers_match
	extras = @handlers.keys ^ @union.type.alternatives.keys
	TypeChecker.assert extras.to_a, [],
	                   "Merge handlers unknown alternatives: #{extras}"

	@union.type.alternatives.each do |k, atype|
		atype.nil? || TypeChecker.assert(
			@handlers.fetch_input_type(k),
			atype,
			"Handler argument does not match alternative type: #{atype}"
		)
	end
end

#type ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 826

def type
	@type ||= @handlers.output_type(@merge.type)
end