dsl_scope_capture

🧩 Capturing Lexical Scope in DSLs

When building internal DSLs, define_method can capture outer variables, enabling clean and expressive APIs. By closing over local variables, you can generate methods that remember the context in which they were defined.

class ConfigDSL
  def initialize
    @settings = {}
  end

  def setting(name, &block)
    # Capture the block and name for later invocation
    define_method(name) do |*args|
      @settings[name] = block.call(*args)
    end
  end

  def settings
    @settings
  end
end

# Usage
dsl = ConfigDSL.new
dsl.setting(:timeout) { 5 * 60 }
dsl.timeout        # => 300
dsl.settings       # => { timeout: 300 }