Introduce a new class Reline::Face to configure character attributes

.gitignore

@@ -2,7 +2,6 @@
 /.yardoc
 /_yardoc/
 /coverage/
-/doc/
 /pkg/
 /spec/reports/
 /tmp/

Gemfile

@@ -12,3 +12,4 @@ end
 gem 'bundler'
 gem 'rake'
 gem 'test-unit'
+gem 'test-unit-rr'

README.md

@@ -55,6 +55,13 @@ end
 
 See also: [test/reline/yamatanooroti/multiline_repl](https://github.com/ruby/reline/blob/master/test/reline/yamatanooroti/multiline_repl)
 
+## Documentation
+
+### Reline::Face
+
+You can modify the text color and text decorations in your terminal emulator.
+See [doc/reline/face.md](./doc/reline/face.md)
+
 ## Contributing
 
 Bug reports and pull requests are welcome on GitHub at https://github.com/ruby/reline.

doc/reline/face.md

@@ -0,0 +1,108 @@
+# Face
+
+With the `Reline::Face` class, you can modify the text color and text decorations in your terminal emulator.
+This is primarily used to customize the appearance of the method completion dialog in IRB.
+
+## Usage
+
+### ex: Change the background color of the completion dialog cyan to blue
+
+```ruby
+Reline::Face.config(:completion_dialog) do |conf|
+  conf.define :default, foreground: :white, background: :blue
+  #                                                     ^^^^^ `:cyan` by default
+  conf.define :enhanced, foreground: :white, background: :magenta
+  conf.define :scrollbar, foreground: :white, background: :blue
+end
+```
+
+If you provide the above code to an IRB session in some way, you can apply the configuration.
+It's generally done by writing it in `.irbrc`.
+
+Regarding `.irbrc`, please refer to the following link: [https://docs.ruby-lang.org/en/master/IRB.html](https://docs.ruby-lang.org/en/master/IRB.html)
+
+## Available parameters
+
+`Reline::Face` internally creates SGR (Select Graphic Rendition) code according to the block parameter of `Reline::Face.config` method.
+
+| Key         | Value             | SGR Code (numeric part following "\e[")|
+|:------------|:------------------|-----:|
+| :foreground | :black            | 30   |
+|             | :red              | 31   |
+|             | :green            | 32   |
+|             | :yellow           | 33   |
+|             | :blue             | 34   |
+|             | :magenta          | 35   |
+|             | :cyan             | 36   |
+|             | :white            | 37   |
+|             | :bright_black     | 90   |
+|             | :gray             | 90   |
+|             | :bright_red       | 91   |
+|             | :bright_green     | 92   |
+|             | :bright_yellow    | 93   |
+|             | :bright_blue      | 94   |
+|             | :bright_magenta   | 95   |
+|             | :bright_cyan      | 96   |
+|             | :bright_white     | 97   |
+| :background | :black            | 40   |
+|             | :red              | 41   |
+|             | :green            | 42   |
+|             | :yellow           | 43   |
+|             | :blue             | 44   |
+|             | :magenta          | 45   |
+|             | :cyan             | 46   |
+|             | :white            | 47   |
+|             | :bright_black     | 100  |
+|             | :gray             | 100  |
+|             | :bright_red       | 101  |
+|             | :bright_green     | 102  |
+|             | :bright_yellow    | 103  |
+|             | :bright_blue      | 104  |
+|             | :bright_magenta   | 105  |
+|             | :bright_cyan      | 106  |
+|             | :bright_white     | 107  |
+| :style      | :reset            | 0    |
+|             | :bold             | 1    |
+|             | :faint            | 2    |
+|             | :italicized       | 3    |
+|             | :underlined       | 4    |
+|             | :slowly_blinking  | 5    |
+|             | :blinking         | 5    |
+|             | :rapidly_blinking | 6    |
+|             | :negative         | 7    |
+|             | :concealed        | 8    |
+|             | :crossed_out      | 9    |
+
+- The value for `:style` can be both a Symbol and an Array
+    ```ruby
+      # Single symbol
+      conf.define :default, style: :bold
+      # Array
+      conf.define :default, style: [:bold, :negative]
+    ```
+- The availability of specific SGR codes depends on your terminal emulator
+- You can specify a hex color code to `:foreground` and `:background` color like `foreground: "#FF1020"`. Its availability also depends on your terminal emulator
+
+## Debugging
+
+You can see the current Face configuration by `Reline::Face.configs` method
+
+Example:
+
+```ruby
+irb(main):001:0> Reline::Face.configs
+=>
+{:default=>
+  {:default=>{:style=>:reset, :escape_sequence=>"\e[0m"},
+   :enhanced=>{:style=>:reset, :escape_sequence=>"\e[0m"},
+   :scrollbar=>{:style=>:reset, :escape_sequence=>"\e[0m"}},
+ :completion_dialog=>
+  {:default=>{:foreground=>:white, :background=>:cyan, :escape_sequence=>"\e[0m\e[37;46m"},
+   :enhanced=>{:foreground=>:white, :background=>:magenta, :escape_sequence=>"\e[0m\e[37;45m"},
+   :scrollbar=>{:foreground=>:white, :background=>:cyan, :escape_sequence=>"\e[0m\e[37;46m"}}}
+```
+
+## Backlog
+
+- Support for 256-color terminal emulator. Fallback hex color code such as "#FF1020" to 256 colors
+

lib/reline.rb

@@ -7,6 +7,7 @@
 require 'reline/line_editor'
 require 'reline/history'
 require 'reline/terminfo'
+require 'reline/face'
 require 'rbconfig'
 
 module Reline
@@ -36,10 +37,8 @@ def match?(other)
   DialogRenderInfo = Struct.new(
     :pos,
     :contents,
-    :bg_color,
-    :pointer_bg_color,
-    :fg_color,
-    :pointer_fg_color,
+    :face,
+    :bg_color, # For the time being, this line should stay here for the compatibility with IRB.
     :width,
     :height,
     :scrollbar,
@@ -260,10 +259,7 @@ def get_screen_size
         contents: result,
         scrollbar: true,
         height: [15, preferred_dialog_height].min,
-        bg_color: 46,
-        pointer_bg_color: 45,
-        fg_color: 37,
-        pointer_fg_color: 37
+        face: :completion_dialog
       )
     }
     Reline::DEFAULT_DIALOG_CONTEXT = Array.new
@@ -606,4 +602,6 @@ def self.update_iogate
   io
 end
 
+Reline::Face.load_initial_config
+
 Reline::HISTORY = Reline::History.new(Reline.core.config)

lib/reline/face.rb

@@ -0,0 +1,157 @@
+# frozen_string_literal: true
+
+class Reline::Face
+  SGR_PARAMETERS = {
+    foreground: {
+      black: 30,
+      red: 31,
+      green: 32,
+      yellow: 33,
+      blue: 34,
+      magenta: 35,
+      cyan: 36,
+      white: 37,
+      bright_black: 90,
+      gray: 90,
+      bright_red: 91,
+      bright_green: 92,
+      bright_yellow: 93,
+      bright_blue: 94,
+      bright_magenta: 95,
+      bright_cyan: 96,
+      bright_white: 97
+    },
+    background: {
+      black: 40,
+      red: 41,
+      green: 42,
+      yellow: 43,
+      blue: 44,
+      magenta: 45,
+      cyan: 46,
+      white: 47,
+      bright_black: 100,
+      gray: 100,
+      bright_red: 101,
+      bright_green: 102,
+      bright_yellow: 103,
+      bright_blue: 104,
+      bright_magenta: 105,
+      bright_cyan: 106,
+      bright_white: 107,
+    },
+    style: {
+      reset: 0,
+      bold: 1,
+      faint: 2,
+      italicized: 3,
+      underlined: 4,
+      slowly_blinking: 5,
+      blinking: 5,
+      rapidly_blinking: 6,
+      negative: 7,
+      concealed: 8,
+      crossed_out: 9
+    }
+  }.freeze
+
+  class Config
+    ESSENTIAL_DEFINE_NAMES = %i(default enhanced scrollbar).freeze
+    RESET_SGR = "\e[0m".freeze
+
+    def initialize(name, &block)
+      @definition = {}
+      block.call(self)
+      ESSENTIAL_DEFINE_NAMES.each do |name|
+        @definition[name] ||= { style: :reset, escape_sequence: RESET_SGR }
+      end
+    end
+
+    attr_reader :definition
+
+    def define(name, **values)
+      values[:escape_sequence] = format_to_sgr(values.to_a).freeze
+      @definition[name] = values
+    end
+
+    def [](name)
+      @definition.dig(name, :escape_sequence) or raise ArgumentError, "unknown face: #{name}"
+    end
+
+    private
+
+    def sgr_rgb(key, value)
+      return nil unless rgb_expression?(value)
+      case key
+      when :foreground
+       "38;2;"
+      when :background
+        "48;2;"
+      end + value[1, 6].scan(/../).map(&:hex).join(";")
+    end
+
+    def format_to_sgr(ordered_values)
+      sgr = "\e[" + ordered_values.map do |key_value|
+        key, value = key_value
+        case key
+        when :foreground, :background
+          case value
+          when Symbol
+            SGR_PARAMETERS[key][value]
+          when String
+            sgr_rgb(key, value)
+          end
+        when :style
+          [ value ].flatten.map do |style_name|
+            SGR_PARAMETERS[:style][style_name]
+          end.then do |sgr_parameters|
+            sgr_parameters.include?(nil) ? nil : sgr_parameters
+          end
+        end.then do |rendition_expression|
+          unless rendition_expression
+            raise ArgumentError, "invalid SGR parameter: #{value.inspect}"
+          end
+          rendition_expression
+        end
+      end.join(';') + "m"
+      sgr == RESET_SGR ? RESET_SGR : RESET_SGR + sgr
+    end
+
+    def rgb_expression?(color)
+      color.respond_to?(:match?) and color.match?(/\A#[0-9a-fA-F]{6}\z/)
+    end
+  end
+
+  private_constant :SGR_PARAMETERS, :Config
+
+  def self.[](name)
+    @configs[name]
+  end
+
+  def self.config(name, &block)
+    @configs ||= {}
+    @configs[name] = Config.new(name, &block)
+  end
+
+  def self.configs
+    @configs.transform_values(&:definition)
+  end
+
+  def self.load_initial_config
+    config(:default) do |conf|
+      conf.define :default, style: :reset
+      conf.define :enhanced, style: :reset
+      conf.define :scrollbar, style: :reset
+    end
+    config(:completion_dialog) do |conf|
+      conf.define :default, foreground: :white, background: :cyan
+      conf.define :enhanced, foreground: :white, background: :magenta
+      conf.define :scrollbar, foreground: :white, background: :cyan
+    end
+  end
+
+  def self.reset_to_initial_config
+    @configs = {}
+    load_initial_config
+  end
+end

lib/reline/line_editor.rb

@@ -831,27 +831,24 @@ def add_dialog_proc(name, p, context = nil)
       dialog.column = 0
       dialog.width = @screen_size.last
     end
+    face = Reline::Face[dialog_render_info.face || :default]
+    scrollbar_sgr = face[:scrollbar]
+    default_sgr = face[:default]
+    enhanced_sgr = face[:enhanced]
     dialog.contents = contents.map.with_index do |item, i|
-      if i == pointer
-        fg_color = dialog_render_info.pointer_fg_color
-        bg_color = dialog_render_info.pointer_bg_color
-      else
-        fg_color = dialog_render_info.fg_color
-        bg_color = dialog_render_info.bg_color
-      end
+      line_sgr = i == pointer ? enhanced_sgr : default_sgr
       str_width = dialog.width - (scrollbar_pos.nil? ? 0 : @block_elem_width)
       str = padding_space_with_escape_sequences(Reline::Unicode.take_range(item, 0, str_width), str_width)
-      colored_content = "\e[#{bg_color}m\e[#{fg_color}m#{str}"
+      colored_content = "#{line_sgr}#{str}"
       if scrollbar_pos
-        color_seq = "\e[37m"
         if scrollbar_pos <= (i * 2) and (i * 2 + 1) < (scrollbar_pos + bar_height)
-          colored_content + color_seq + @full_block
+          colored_content + scrollbar_sgr + @full_block
         elsif scrollbar_pos <= (i * 2) and (i * 2) < (scrollbar_pos + bar_height)
-          colored_content + color_seq + @upper_half_block
+          colored_content + scrollbar_sgr + @upper_half_block
         elsif scrollbar_pos <= (i * 2 + 1) and (i * 2) < (scrollbar_pos + bar_height)
-          colored_content + color_seq + @lower_half_block
+          colored_content + scrollbar_sgr + @lower_half_block
         else
-          colored_content + color_seq + ' ' * @block_elem_width
+          colored_content + scrollbar_sgr + ' ' * @block_elem_width
         end
       else
         colored_content

test/reline/helper.rb

@@ -4,6 +4,7 @@
 
 require 'reline'
 require 'test/unit'
+require 'test/unit/rr'
 
 begin
   require 'rbconfig'