How to correctly define a block for instance_exec

[aaronmallen]

What is the correct way to define the signature for an instance_exec block?

class ParameterBuild
  def define(parameter_name, &)
    @current_parameter = @data[parameter_name.to_sym] ||=
      PARAMETER_DEFAULTS.transform_values { |value| value == UNSPECIFIED ? value : value.dup }
                        .merge(name: parameter_name.to_sym)
    instance_exec(&) if block_given?
    self
  end
end

class ParameterBuilder
  def define: (String | Symbol parameter_name) ?{ (self) -> self } -> self
end

class BaseConstraint
  def self.parameter(parameter_name, &)
    parameter_builder.define(parameter_name, &).build!
  end

  parameter :my_param do
    ...
  end
end

class BaseConstraint
  def self.parameter: (String | Symbol parameter_name) ?{ (DSL::ParameterBuilder) -> DSL::ParameterBuilder } -> void
end

RBS::Test::Tester::TypeError:
  TypeError: [ParameterBuilder#define] BlockArgumentError: expected method type (::String | ::Symbol parameter_name) ?{ (self) -> self } -> self

[soutaro]

Seems like you can specify [self: self] constraint to the block types. And probably you need non-nil check of the block variable.

class ParameterBuilder
  def define: (String | Symbol parameter_name) ?{ (?) [self: self] -> void } -> self
end

class BaseConstraint
  attr_reader self.parameter_builder: ParameterBuilder

  def self.parameter: (String | Symbol parameter_name) ?{ (ParameterBuilder) [self: ParameterBuilder] -> ParameterBuilder } -> void
end

class ParameterBuilder
  def define(parameter_name, &block)
    instance_exec(&block) if block
    self
  end
end

class BaseConstraint
  def self.parameter(parameter_name, &)
    parameter_builder.define(parameter_name, &)
  end
end

Steep doesn't infer based on block_given? calls currently. A possible feature improvement.

[aaronmallen]

def define(parameter_name, &block)
  @current_parameter = @data[parameter_name.to_sym] ||=
    PARAMETER_DEFAULTS.transform_values { |value| value == UNSPECIFIED ? value : value.dup }.merge(name: parameter_name.to_sym)
  instance_exec(&block) if block
  self
end

class ParameterBuilder
  def define: (String | Symbol parameter_name) ?{ (?) [self: self] -> void } -> self
  
  def description: (String description_string) -> self
  alias desc description
end

class BaseConstraint
  def self.parameter: (String | Symbol parameter_name) { (DSL::ParameterBuilder) [self: DSL::ParameterBuilder] -> void } -> void
end

Failure/Error:
  desc ''

NoMethodError:
  undefined method `desc' for BaseConstraint:Class

Keep in mind the block most definitely works and specs pass with RBS disabled...