Class: Dhall::Union

Inherits:

Expression

• Object
• Expression
• Dhall::Union

Defined in:

lib/dhall/ast.rb,
lib/dhall/binary.rb,
lib/dhall/normalize.rb

Direct Known Subclasses

Enum

Class Method Summary

• .decode(tag, value, alternatives) ⇒ Object
• .from(alts, tag, value) ⇒ Object

Instance Method Summary

• #as_json ⇒ Object
• #extract ⇒ Object
• #normalize ⇒ Object
• #reduce(handlers) ⇒ Object
• #selection_syntax ⇒ Object
• #syntax ⇒ Object
• #to_s ⇒ Object

Methods inherited from Expression

#&, #*, #+, #annotate, #as_dhall, #cache_key, #call, #concat, #deep_merge, #deep_merge_type, #dhall_eq, #digest, #fetch, #fusion, #merge, #resolve, #shift, #slice, #substitute, #to_binary, #to_cbor, #to_proc, #|

Class Method Details

.decode(tag, value, alternatives) ⇒ Object

# File 'lib/dhall/binary.rb', line 184

def self.decode(tag, value, alternatives)
  new(
    tag:          tag,
    value:        Dhall.decode(value),
    alternatives: UnionType.decode(alternatives)
  )
end

.from(alts, tag, value) ⇒ Object

# File 'lib/dhall/ast.rb', line 1024

def self.from(alts, tag, value)
  if value.nil?
    Enum.new(tag: tag, alternatives: alts.without(tag))
  else
    new(
      tag:          tag,
      value:        TypeAnnotation.new(value: value, type: alts[tag]),
      alternatives: alts.without(tag)
    )
  end
end

Instance Method Details

#as_json ⇒ Object

# File 'lib/dhall/ast.rb', line 1071

def as_json
  if value.respond_to?(:type)
    syntax.as_json
  else
    [12, tag, value&.as_json, alternatives.as_json.last]
  end
end

#extract ⇒ Object

# File 'lib/dhall/ast.rb', line 1040

def extract
  if value.is_a?(TypeAnnotation)
    value.value
  else
    value
  end
end

#normalize ⇒ Object

# File 'lib/dhall/normalize.rb', line 378

def normalize
  val = if value.is_a?(TypeAnnotation)
    value.with(ExpressionVisitor.new(&:normalize).visit(value))
  else
    value&.normalize
  end

  with(value: val, alternatives: alternatives.normalize)
end

#reduce(handlers) ⇒ Object

# File 'lib/dhall/ast.rb', line 1048

def reduce(handlers)
  handlers = handlers.to_h
  handler = handlers.fetch(tag.to_sym) { handlers.fetch(tag) }
  (handler.respond_to?(:to_proc) ? handler.to_proc : handler)
    .call(extract)
end

#selection_syntax ⇒ Object

# File 'lib/dhall/ast.rb', line 1055

def selection_syntax
  RecordSelection.new(
    record:   alternatives.merge(
      UnionType.new(alternatives: { tag => value&.type })
    ),
    selector: tag
  )
end

#syntax ⇒ Object

# File 'lib/dhall/ast.rb', line 1064

def syntax
  Application.new(
    function: selection_syntax,
    argument: value.is_a?(TypeAnnotation) ? value.value : value
  )
end

#to_s ⇒ Object

# File 'lib/dhall/ast.rb', line 1036

def to_s
  extract.to_s
end