Class: RBS::AST::TypeParam

Inherits:
Object
  • Object
show all
Includes:
_ToJson
Defined in:
lib/rbs/ast/type_param.rb,
sig/type_param.rbs

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name:, variance:, upper_bound:, lower_bound:, location:, default_type: nil, unchecked: false) ⇒ TypeParam

Returns a new instance of TypeParam.

Parameters:

  • name: (Symbol)
  • variance: (variance)
  • upper_bound: (Types::t, nil)
  • lower_bound: (Types::t, nil)
  • location: (loc, nil)
  • default_type: (Types::t, nil) (defaults to: nil)
  • unchecked: (Boolean) (defaults to: false) 


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# File 'lib/rbs/ast/type_param.rb', line 8

def initialize(name:, variance:, upper_bound:, lower_bound:, location:, default_type: nil, unchecked: false)
  @name = name
  @variance = variance
  @upper_bound_type = upper_bound
  @lower_bound_type = lower_bound
  @location = location
  @default_type = default_type
  @unchecked = unchecked
end

Instance Attribute Details

#default_type ⇒ Types::t? (readonly)

Returns the value of attribute default_type.

Returns:

  • (Types::t, nil) 


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# File 'lib/rbs/ast/type_param.rb', line 6

def default_type
  @default_type
end

#location ⇒ loc? (readonly)

Returns the value of attribute location.

Returns:

  • (loc, nil) 


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# File 'lib/rbs/ast/type_param.rb', line 6

def location
  @location
end

#lower_bound_type ⇒ Types::t? (readonly)

Returns the value of attribute lower_bound_type.

Returns:

  • (Types::t, nil) 


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# File 'lib/rbs/ast/type_param.rb', line 6

def lower_bound_type
  @lower_bound_type
end

#name ⇒ Symbol (readonly)

Returns the value of attribute name.

Returns:

  • (Symbol) 


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# File 'lib/rbs/ast/type_param.rb', line 6

def name
  @name
end

#upper_bound_type ⇒ Types::t? (readonly)

Returns the value of attribute upper_bound_type.

Returns:

  • (Types::t, nil) 


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# File 'lib/rbs/ast/type_param.rb', line 6

def upper_bound_type
  @upper_bound_type
end

#variance ⇒ variance (readonly)

Returns the value of attribute variance.

Returns:



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# File 'lib/rbs/ast/type_param.rb', line 6

def variance
  @variance
end

Class Method Details

.application(params, args) ⇒ Substitution?

Returns an application with respect to type params' default

Parameters:

Returns:



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# File 'sig/type_param.rbs', line 92

def self.application(params, args)
  if params.empty?
    return nil
  end

  optional_params, required_params = params.partition {|param| param.default_type }

  param_subst = Substitution.new()
  app_subst = Substitution.new()

  required_params.zip(args.take(required_params.size)).each do |param, arg|
    arg ||= Types::Bases::Any.new(location: nil)
    param_subst.add(from: param.name, to: arg)
    app_subst.add(from: param.name, to: arg)
  end

  optional_params.each do |param|
    param_subst.add(from: param.name, to: Types::Bases::Any.new(location: nil))
  end

  optional_params.zip(args.drop(required_params.size)).each do |param, arg|
    if arg
      app_subst.add(from: param.name, to: arg)
    else
      param.default_type or raise
      app_subst.add(from: param.name, to: param.default_type.sub(param_subst))
    end
  end

  app_subst
end

.normalize_args(params, args) ⇒ Array[Types::t]

Returns an array of type args, that fills omitted types with the defaults

interface _Foo[T, S = untyped]
end

Normalizing type args with _Foo works as following:

_Foo[String]                   # => _Foo[String, untyped]
_Foo[String, Integer]          # => _Foo[String, Integer]
_Foo                           # => _Foo                            (Omitting missing args)
_Foo[String, Integer, untyped] # => _Foo[String, Integer, untyped]  (Keeping extra args)

Note that it allows invalid arities, returning the args immediately.

Parameters:

Returns:

  • (Array[Types::t]) 


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# File 'sig/type_param.rbs', line 112

def self.normalize_args(params, args)
  app = application(params, args) or return args

  min_count = params.count { _1.default_type.nil? }
  unless min_count <= args.size && args.size <= params.size
    return args
  end

  params.zip(args).filter_map do |param, arg|
    if arg
      arg
    else
      if param.default_type
        param.default_type.sub(app)
      else
        Types::Bases::Any.new(location: nil)
      end
    end
  end
end

.rename(params, new_names:) ⇒ Array[TypeParam]

Rename type parameter name.

The renaming cannot be done separately because a set of TypeParam decls may be mutual recursive.

Example:

  • Renaming A -> X, B -> Y
  • Input [A, B < _Pushable[A]]
  • Result [X, Y < _Pushable[X]]

Parameters:

  • (Array[TypeParam])
  • new_names: (Array[Symbol])

Returns:



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# File 'sig/type_param.rbs', line 79

def self.rename(params, new_names:)
  raise unless params.size == new_names.size

  subst = Substitution.build(new_names, Types::Variable.build(new_names))

  params.map.with_index do |param, index|
    new_name = new_names[index]

    TypeParam.new(
      name: new_name,
      variance: param.variance,
      upper_bound: param.upper_bound_type&.map_type {|type| type.sub(subst) },
      lower_bound: param.lower_bound_type&.map_type {|type| type.sub(subst) },
      location: param.location,
      default_type: param.default_type&.map_type {|type| type.sub(subst) }
    ).unchecked!(param.unchecked?)
  end
end

.resolve_variables(params) ⇒ void

This method returns an undefined value.

Helper function to resolve class instance types to type variables.

We need this step because RBS language has an identical syntax for both unqualified class instance types and type variables. String may be an instance of ::String class or type variable depending on the list of bound type variables.

So, we need second pass to parse the following generics parameter declaration.

class Foo[X < _Each[Y], Y]
                  # ^ We want this `Y` to be a type variable.
end

Parameters:



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# File 'sig/type_param.rbs', line 65

def self.resolve_variables(params)
  return if params.empty?

  vars = Set.new(params.map(&:name))

  params.map! do |param|
    param.map_type {|bound| _ = subst_var(vars, bound) }
  end
end

.subst_var(vars, type) ⇒ Types::t

Parameters:

  • (Set[Symbol])
  • (Types::t)

Returns:

  • (Types::t) 


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# File 'lib/rbs/ast/type_param.rb', line 102

def self.subst_var(vars, type)
  case type
  when Types::ClassInstance
    namespace = type.name.namespace
    if namespace.relative? && namespace.empty? && vars.member?(type.name.name)
      return Types::Variable.new(name: type.name.name, location: type.location)
    end
  end

  type.map_type {|t| subst_var(vars, t) }
end

.validate(type_params) ⇒ Array[TypeParam]?

Validates TypeParams if it refers another optional type params

  • Returns array of TypeParam objects that refers other optional type params
  • Returns nil if all type params are valid

Parameters:

Returns:



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# File 'sig/type_param.rbs', line 88

def self.validate(type_params)
  optionals = type_params.filter {|param| param.default_type }

  optional_param_names = optionals.map(&:name).sort

  optionals.filter! do |param|
    default_type = param.default_type or raise
    optional_param_names.any? { default_type.free_variables.include?(_1) }
  end

  unless optionals.empty?
    optionals
  end
end

Instance Method Details

#==(other) ⇒ Boolean Also known as: eql?

Parameters:

  • (Object)

Returns:

  • (Boolean) 


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# File 'lib/rbs/ast/type_param.rb', line 41

def ==(other)
  other.is_a?(TypeParam) &&
    other.name == name &&
    other.variance == variance &&
    other.upper_bound_type == upper_bound_type &&
    other.lower_bound_type == lower_bound_type &&
    other.default_type == default_type &&
    other.unchecked? == unchecked?
end

#hash ⇒ Integer

Returns:

  • (Integer) 


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# File 'lib/rbs/ast/type_param.rb', line 53

def hash
  self.class.hash ^ name.hash ^ variance.hash ^ upper_bound_type.hash ^ lower_bound_type.hash ^ unchecked?.hash ^ default_type.hash
end

#lower_bound ⇒ Object 



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# File 'lib/rbs/ast/type_param.rb', line 25

def lower_bound
  case lower_bound_type
  when Types::ClassInstance, Types::ClassSingleton, Types::Interface
    lower_bound_type
  end
end

#map_type {|arg0| ... } ⇒ TypeParam

Yields:

Yield Parameters:

  • arg0 (Types::t)

Yield Returns:

  • (Types::t)

Returns:



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# File 'lib/rbs/ast/type_param.rb', line 69

def map_type(&block)
  if b = upper_bound_type
    _upper_bound_type = yield(b)
  end

  if b = lower_bound_type
    _lower_bound_type = yield(b)
  end

  if dt = default_type
    _default_type = yield(dt)
  end

  TypeParam.new(
    name: name,
    variance: variance,
    upper_bound: _upper_bound_type,
    lower_bound: _lower_bound_type,
    location: location,
    default_type: _default_type
  ).unchecked!(unchecked?)
end

#to_json(state = JSON::State.new) ⇒ Object 



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# File 'lib/rbs/ast/type_param.rb', line 57

def to_json(state = JSON::State.new)
  {
    name: name,
    variance: variance,
    unchecked: unchecked?,
    location: location,
    upper_bound: upper_bound_type,
    lower_bound: lower_bound_type,
    default_type: default_type
  }.to_json(state)
end

#to_s ⇒ String

Returns:

  • (String) 


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# File 'lib/rbs/ast/type_param.rb', line 133

def to_s
  s = +""

  if unchecked?
    s << "unchecked "
  end

  case variance
  when :invariant
    # nop
  when :covariant
    s << "out "
  when :contravariant
    s << "in "
  end

  s << name.to_s

  if type = upper_bound_type
    s << " < #{type}"
  end

  if type = lower_bound_type
    s << " > #{type}"
  end

  if dt = default_type
    s << " = #{dt}"
  end

  s
end

#unchecked!(value = true) ⇒ self

Parameters:

  • (boolish)

Returns:

  • (self) 


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# File 'lib/rbs/ast/type_param.rb', line 32

def unchecked!(value = true)
  @unchecked = value ? true : false
  self
end

#unchecked? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rbs/ast/type_param.rb', line 37

def unchecked?
  @unchecked
end

#upper_bound ⇒ Object 



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# File 'lib/rbs/ast/type_param.rb', line 18

def upper_bound
  case upper_bound_type
  when Types::ClassInstance, Types::ClassSingleton, Types::Interface
    upper_bound_type
  end
end