Class: Dhall::TypeChecker::RecordProjection

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

Instance Method Summary collapse

Constructor Details

#initialize(projection) ⇒ RecordProjection

Returns a new instance of RecordProjection.



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# File 'lib/dhall/typecheck.rb', line 635

def initialize(projection)
  @projection = projection
  @record = TypeChecker.for(projection.record)
  @selectors = projection.selectors
end

Instance Method Details

#annotate(context) ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 641

def annotate(context)
  arecord = @record.annotate(context)

  TypeChecker.assert arecord.type.class.name, "Dhall::RecordType",
                     "RecordProjection on #{arecord.type}"

  slice = arecord.type.slice(@selectors)
  TypeChecker.assert slice.keys, @selectors,
                     "#{arecord.type} missing one of: #{@selectors}"

  Dhall::TypeAnnotation.new(
    value: @projection.with(record: arecord),
    type:  slice
  )
end