Class: Dhall::TypeChecker::RecordSelection::Selector

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

Direct Known Subclasses

TypeSelector

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(type) ⇒ Selector

Returns a new instance of Selector.



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# File 'lib/dhall/typecheck.rb', line 549

def initialize(type)
	@fetch_from = type.record
end

Class Method Details

.for(annotated_record) ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 539

def self.for(annotated_record)
	if annotated_record.type == Builtins[:Type]
		TypeSelector.new(annotated_record.value)
	elsif annotated_record.type.class == Dhall::RecordType
		new(annotated_record.type)
	else
		raise TypeError, "RecordSelection on #{annotated_record.type}"
	end
end

Instance Method Details

#select(selector) ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 553

def select(selector)
	@fetch_from.fetch(selector) do
		raise TypeError, "#{@fetch_from} has no field #{@selector}"
	end
end