Change to collapse parser various arguments into parameters list

lib/tty/option.rb

@@ -11,6 +11,9 @@ module Option
     # Raised when number of arguments doesn't match
     InvalidArity = Class.new(Error)
 
+    # Raised when attempting to register already registered parameter
+    ParameterConflict = Class.new(Error)
+
     # Enhance object with command line option parsing
     #
     # @api public
@@ -27,8 +30,7 @@ def params
       end
 
       def parse(argv = ARGV, env = ENV)
-        parser = Parser.new(self.class.arguments, self.class.keywords,
-                            self.class.environments)
+        parser = Parser.new(self.class.parameters)
         @params = parser.parse(argv, env)
       end
     end

lib/tty/option/dsl.rb

@@ -3,6 +3,7 @@
 require_relative "parameter/argument"
 require_relative "parameter/environment"
 require_relative "parameter/keyword"
+require_relative "parameters"
 
 module TTY
   module Option
@@ -11,7 +12,7 @@ module DSL
       #
       # @api public
       def argument(name, **settings, &block)
-        arguments << Parameter::Argument.create(name.to_sym, **settings, &block)
+        parameters << Parameter::Argument.create(name.to_sym, **settings, &block)
       end
 
       # Specify environment variable
@@ -21,7 +22,7 @@ def argument(name, **settings, &block)
       #
       # @api public
       def environment(name, **settings, &block)
-        environments << Parameter::Environment.create(name, **settings, &block)
+        parameters << Parameter::Environment.create(name.to_sym, **settings, &block)
       end
       alias env environment
 
@@ -32,19 +33,14 @@ def environment(name, **settings, &block)
       #
       # @api public
       def keyword(name, **settings, &block)
-        keywords << Parameter::Keyword.create(name.to_sym, **settings, &block)
+        parameters << Parameter::Keyword.create(name.to_sym, **settings, &block)
       end
 
-      def arguments
-        @arguments ||= []
-      end
-
-      def environments
-        @environments ||= []
-      end
-
-      def keywords
-        @keywords ||= []
+      # Holds all parameters
+      #
+      # @api public
+      def parameters
+        @parameters ||= Parameters.new
       end
     end # DSL
   end # Option

lib/tty/option/parameters.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require "set"
+
+module TTY
+  module Option
+    # A collection to hold all parameters
+    class Parameters
+      # A list of arguments
+      attr_reader :arguments
+
+      # A list of keywords
+      attr_reader :keywords
+
+      # A list of environments
+      attr_reader :environments
+
+      # A list of all parameters
+      attr_reader :all
+
+      # A parameters list
+      #
+      # @api private
+      def initialize
+        @arguments = []
+        @environments = []
+        @keywords = []
+        @all = []
+
+        @registered_names = Set.new
+      end
+
+      # Add parameter
+      #
+      # @api public
+      def <<(parameter)
+        if @registered_names.include?(parameter.name)
+          raise ParameterConflict,
+                "already registered parameter #{parameter.name.inspect}"
+        else
+          @registered_names << parameter.name
+        end
+
+        @all << parameter
+        arr = instance_variable_get("@#{parameter.to_sym}s")
+        arr.send :<<, parameter
+      end
+      alias add <<
+    end # Parameters
+  end # Option
+end # TTY

lib/tty/option/parser.rb

@@ -7,17 +7,20 @@
 module TTY
   module Option
     class Parser
+      %w[
+        arguments
+        environments
+        keywords
+      ].each do |name|
+        define_method(name) do
+          parameters.send(name)
+        end
+      end
 
-      attr_reader :arguments
-
-      attr_reader :environments
-
-      attr_reader :keywords
+      attr_reader :parameters
 
-      def initialize(arguments, keywords, environments)
-        @arguments = arguments
-        @keywords = keywords
-        @environments = environments
+      def initialize(parameters)
+        @parameters = parameters
       end
 
       def parse(argv, env)

spec/unit/parse_spec.rb

@@ -12,6 +12,17 @@ def new_command(&block)
 end
 
 RSpec.describe TTY::Option do
+  it "doesn't allow to register same name parameter" do
+    expect {
+      command do
+        argument :foo
+
+        keyword :foo
+      end
+    }.to raise_error(TTY::Option::ParameterConflict,
+                    "already registered parameter :foo")
+  end
+
   context "argument" do
     it "reads a single argument" do
       cmd = new_command do