RBS::VarianceCalculator

Attributes

builder[R]

Public Class Methods

new(builder:) click to toggle source

 
               # File rbs-2.1.0/lib/rbs/variance_calculator.rb, line 76
def initialize(builder))
  @builder = builder
end

Public Instance Methods

env() click to toggle source

 
               # File rbs-2.1.0/lib/rbs/variance_calculator.rb, line 80
def env
  builder.env
end

function(type, result:, context:) click to toggle source

 
               # File rbs-2.1.0/lib/rbs/variance_calculator.rb, line 164
def function(type, result,, context))
  type.each_param do |param|
    type(param.type, result: result, context: negate(context))
  end
  type(type.return_type, result: result, context: context)
end

in_inherit(name:, args:, variables:) click to toggle source

 
               # File rbs-2.1.0/lib/rbs/variance_calculator.rb, line 96
def in_inherit(name,, args,, variables))
  type = if name.class?
           Types::ClassInstance.new(name: name, args: args, location: nil)
         else
           Types::Interface.new(name: name, args: args, location: nil)
         end

  Result.new(variables: variables).tap do |result|
    type(type, result: result, context: :covariant)
  end
end

in_method_type(method_type:, variables:) click to toggle source

 
               # File rbs-2.1.0/lib/rbs/variance_calculator.rb, line 84
def in_method_type(method_type,, variables))
  result = Result.new(variables: variables)

  function(method_type.type, result: result, context: :covariant)

  if block = method_type.block
    function(block.type, result: result, context: :contravariant)
  end

  result
end

in_type_alias(name:) click to toggle source

 
               # File rbs-2.1.0/lib/rbs/variance_calculator.rb, line 108
def in_type_alias(name))
  decl = env.alias_decls[name].decl or raise
  variables = decl.type_params.each.map(&:name)
  Result.new(variables: variables).tap do |result|
    type(decl.type, result: result, context: :covariant)
  end
end

negate(variance) click to toggle source

 
               # File rbs-2.1.0/lib/rbs/variance_calculator.rb, line 171
def negate(variance)
  case variance
  when :invariant
    :invariant
  when :covariant
    :contravariant
  when :contravariant
    :covariant
  else
    raise
  end
end

type(type, result:, context:) click to toggle source

 
               # File rbs-2.1.0/lib/rbs/variance_calculator.rb, line 116
def type(type, result,, context))
  case type
  when Types::Variable
    if result.include?(type.name)
      case context
      when :covariant
        result.covariant(type.name)
      when :contravariant
        result.contravariant(type.name)
      when :invariant
        result.invariant(type.name)
      end
    end
  when Types::ClassInstance, Types::Interface, Types::Alias
    NoTypeFoundError.check!(type.name,
                            env: env,
                            location: type.location)

    type_params = case type
                  when Types::ClassInstance
                    env.class_decls[type.name].type_params
                  when Types::Interface
                    env.interface_decls[type.name].decl.type_params
                  when Types::Alias
                    env.alias_decls[type.name].decl.type_params
                  end

    type.args.each.with_index do |ty, i|
      if var = type_params[i]
        case var.variance
        when :invariant
          type(ty, result: result, context: :invariant)
        when :covariant
          type(ty, result: result, context: context)
        when :contravariant
          type(ty, result: result, context: negate(context))
        end
      end
    end
  when Types::Proc
    function(type.type, result: result, context: context)
  else
    type.each_type do |ty|
      type(ty, result: result, context: context)
    end
  end
end

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RBS::VarianceCalculator

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