Add support for adding a custom suffix to suggested word completion

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Added
 * Add to line the ability to find a word to complete before the cursor
 * Add ability to complete words
+* Add support for adding a custom suffix to suggested word completion
 * Add :history_size keyword to allow configuration of maximum history size
 * Add the ability to replace a current line in the history buffer
 * Add support for preserving edits to lines stored in history

lib/tty/reader.rb

@@ -62,6 +62,11 @@ def self.windows?
     # @api public
     attr_reader :completion_handler
 
+    # The suffix to add to suggested word completion
+    #
+    # @api public
+    attr_reader :completion_suffix
+
     attr_reader :console
 
     attr_reader :cursor
@@ -86,14 +91,16 @@ def self.windows?
     #   exclude lines from history, by default all lines are stored
     # @param [Proc] completion_handler
     #   the hanlder for finding word completion suggestions
+    # @param [String] completion_suffix
+    #   the suffix to add to suggested word completion
     #
     # @api public
     def initialize(input: $stdin, output: $stdout, interrupt: :error,
                    env: ENV, track_history: true, history_cycle: false,
                    history_exclude: History::DEFAULT_EXCLUDE,
                    history_size: History::DEFAULT_SIZE,
                    history_duplicates: false,
-                   completion_handler: nil)
+                   completion_handler: nil, completion_suffix: "")
       @input = input
       @output = output
       @interrupt = interrupt
@@ -104,7 +111,9 @@ def initialize(input: $stdin, output: $stdout, interrupt: :error,
       @history_duplicates = history_duplicates
       @history_size = history_size
       @completion_handler = completion_handler
-      @completer = Completer.new(handler: completion_handler)
+      @completion_suffix = completion_suffix
+      @completer = Completer.new(handler: completion_handler,
+                                 suffix: completion_suffix)
 
       @console = select_console(input)
       @history = History.new(history_size) do |h|
@@ -126,6 +135,17 @@ def completion_handler=(handler)
       @completer.handler = handler
     end
 
+    # Set completion suffix
+    #
+    # @param [String] suffix
+    #   the suffix to add to suggested word completion
+    #
+    # @api public
+    def completion_suffix=(suffix)
+      @completion_suffix = suffix
+      @completer.suffix = suffix
+    end
+
     alias old_subcribe subscribe
 
     # Subscribe to receive key events

lib/tty/reader/completer.rb

@@ -14,14 +14,18 @@ class Completer
       # The handler for finding word completion suggestions
       attr_accessor :handler
 
+      # The suffix to add to suggested word completion
+      attr_accessor :suffix
+
       # The word to complete
       attr_reader :word
 
       # Create a Completer instance
       #
       # @api private
-      def initialize(handler: nil)
+      def initialize(handler: nil, suffix: "")
         @handler = handler
+        @suffix = suffix
         @completions = Completions.new
         @show_initial = false
         @word = ""
@@ -60,7 +64,7 @@ def complete_initial(line)
         completed_word = completions.get
 
         line.remove(word.length)
-        line.insert(completed_word)
+        line.insert(completed_word + suffix)
 
         completed_word
       end
@@ -90,8 +94,11 @@ def complete_next(line)
           completed_word = completions.get
         end
 
-        line.remove(previous_suggestion.length)
-        line.insert(completed_word)
+        length_to_remove = previous_suggestion.length
+        length_to_remove += suffix.length if previous_suggestion != word
+
+        line.remove(length_to_remove)
+        line.insert("#{completed_word}#{suffix unless @show_initial}")
 
         completed_word
       end

spec/unit/complete_word_spec.rb

@@ -144,4 +144,54 @@
 
     expect(answer).to eq(%W[aa\n ab])
   end
+
+  it "adds space suffix to suggested word completion on the first tab" do
+    @completions = %w[aa ab ac]
+    options[:completion_suffix] = " "
+    reader = described_class.new(**options)
+    input << "x " << "a" << "\t" << "\n"
+    input.rewind
+
+    answer = reader.read_line
+
+    expect(answer).to eq("x aa \n")
+  end
+
+  it "adds space suffix to suggested word completion on the second tab" do
+    @completions = %w[aa ab ac]
+    options[:completion_suffix] = " "
+    reader = described_class.new(**options)
+    input << "x " << "a" << "\t" << "\t" << "\n"
+    input.rewind
+
+    answer = reader.read_line
+
+    expect(answer).to eq("x ab \n")
+  end
+
+  it "skips adding space suffix to the original word" do
+    @completions = %w[aa ab ac]
+    options[:completion_suffix] = " "
+    reader = described_class.new(**options)
+    input << "x " << "a" << "\t" << "\t" << "\t" << "\t" << "\n"
+    input.rewind
+
+    answer = reader.read_line
+
+    expect(answer).to eq("x a\n")
+    expect(reader.completion_suffix).to eq(" ")
+  end
+
+  it "adds two chars suffix to suggested word completion" do
+    @completions = %w[aa ab ac]
+    reader = described_class.new(**options)
+    reader.completion_suffix = "??"
+    input << "x " << "a" << "\t" << "\t" << "\n"
+    input.rewind
+
+    answer = reader.read_line
+
+    expect(answer).to eq("x ab??\n")
+    expect(reader.completion_suffix).to eq("??")
+  end
 end