Add Colors module to help users set text colors

lib/dry/cli/colors.rb

@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+
+module Dry
+  class CLI
+    # Collection of functions to colorize text.
+    #
+    # @since 1.3.0
+    module Colors
+      # since 1.3.0
+      def bold(text)
+        ensure_clean_sequence("\e[1m#{text}")
+      end
+
+      # since 1.3.0
+      def black(text)
+        ensure_clean_sequence("\e[30m#{text}")
+      end
+
+      # since 1.3.0
+      def red(text)
+        ensure_clean_sequence("\e[31m#{text}")
+      end
+
+      # since 1.3.0
+      def green(text)
+        ensure_clean_sequence("\e[32m#{text}")
+      end
+
+      # since 1.3.0
+      def yellow(text)
+        ensure_clean_sequence("\e[33m#{text}")
+      end
+
+      # since 1.3.0
+      def blue(text)
+        ensure_clean_sequence("\e[34m#{text}")
+      end
+
+      # since 1.3.0
+      def magenta(text)
+        ensure_clean_sequence("\e[35m#{text}")
+      end
+
+      # since 1.3.0
+      def cyan(text)
+        ensure_clean_sequence("\e[36m#{text}")
+      end
+
+      # since 1.3.0
+      def white(text)
+        ensure_clean_sequence("\e[37m#{text}")
+      end
+
+      # since 1.3.0
+      def on_black(text)
+        ensure_clean_sequence("\e[40m#{text}")
+      end
+
+      # since 1.3.0
+      def on_red(text)
+        ensure_clean_sequence("\e[41m#{text}")
+      end
+
+      # since 1.3.0
+      def on_green(text)
+        ensure_clean_sequence("\e[42m#{text}")
+      end
+
+      # since 1.3.0
+      def on_yellow(text)
+        ensure_clean_sequence("\e[43m#{text}")
+      end
+
+      # since 1.3.0
+      def on_blue(text)
+        ensure_clean_sequence("\e[44m#{text}")
+      end
+
+      # since 1.3.0
+      def on_magenta(text)
+        ensure_clean_sequence("\e[45m#{text}")
+      end
+
+      # since 1.3.0
+      def on_cyan(text)
+        ensure_clean_sequence("\e[46m#{text}")
+      end
+
+      # since 1.3.0
+      def on_white(text)
+        ensure_clean_sequence("\e[47m#{text}")
+      end
+
+      private
+
+      # @since 1.3.0
+      # @api private
+      def ensure_clean_sequence(text)
+        clen_text = text
+        clear = "\e[0m"
+        clen_text += clear unless text.end_with?(clear)
+        clen_text
+      end
+    end
+  end
+end

lib/dry/cli/command.rb

@@ -2,13 +2,16 @@
 
 require "forwardable"
 require "dry/cli/option"
+require "dry/cli/colors"
 
 module Dry
   class CLI
     # Base class for commands
     #
     # @since 0.1.0
     class Command
+      include Colors
+
       # @since 0.1.0
       # @api private
       def self.inherited(base)

spec/support/fixtures/colors

@@ -0,0 +1,49 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+$LOAD_PATH.unshift "#{__dir__}/../../../lib"
+require "dry/cli"
+
+module ColorsDemo
+  extend Dry::CLI::Registry
+
+  class Print < Dry::CLI::Command
+    desc "Demonstrate all available colors"
+
+    # rubocop:disable Metrics/AbcSize
+    def call
+      demo = <<~DEMO
+        # Style ###############################################################
+        Bold: #{bold("This is bold")}
+        # Foreground ##########################################################
+        Black:   #{black("This is black")}
+        Red:     #{red("This is red")}
+        Green:   #{green("This is green")}
+        Yellow:  #{yellow("This is yellow")}
+        Blue:    #{blue("This is blue")}
+        Magenta: #{magenta("This is magenta")}
+        Cyan:    #{cyan("This is cyan")}
+        White:   #{white("This is white")}
+        # Background ##########################################################
+        Black:   #{on_black("This is black")}
+        Red:     #{on_red("This is red")}
+        Green:   #{on_green("This is green")}
+        Yellow:  #{on_yellow("This is yellow")}
+        Blue:    #{on_blue("This is blue")}
+        Magenta: #{on_magenta("This is magenta")}
+        Cyan:    #{on_cyan("This is cyan")}
+        White:   #{on_white("This is white")}
+        # Combinations ########################################################
+        Bold+Foreground:            #{bold(red("This is bold red"))}
+        Bold+Background:            #{bold(on_green("This is bold on green"))}
+        Bold+Foreground+Background: #{bold(red(on_green("This is bold red on green")))}
+      DEMO
+      puts demo
+    end
+    # rubocop:enable Metrics/AbcSize
+  end
+
+  register "print", Print
+end
+
+Dry.CLI(ColorsDemo).call

spec/support/fixtures/foo

@@ -35,7 +35,7 @@ module Foo
         ]
 
         def call(engine: nil, **)
-          puts "console - engine: #{engine}"
+          puts blue(bold("console - engine: ")), magenta(engine.to_s)
         end
       end
 

spec/unit/dry/cli/colors_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+RSpec.describe "Colors" do
+  module Dummy
+    module_function
+
+    include Dry::CLI::Colors
+
+    def only_bold
+      bold("one")
+    end
+
+    def bold_and_black
+      black(bold("two"))
+    end
+  end
+
+  it "doesn't duplicate clean escape sequences" do
+    only_bold = Dummy.only_bold
+    expect(only_bold.end_with?("\e[0m")).to eq(true)
+    expect(only_bold.end_with?("\e[0m\e[0m")).to eq(false)
+    bold_and_black = Dummy.bold_and_black
+    expect(bold_and_black.end_with?("\e[0m")).to eq(true)
+    expect(bold_and_black.end_with?("\e[0m\e[0m")).to eq(false)
+  end
+end