Implement reverse-i-search on ctrl+r, and add a disable_search? h…

…ook.

README.md

@@ -12,10 +12,10 @@ It includes the following features:
 * Hook for Auto formatting
 * Hook for Auto indentation
 * Hook for Auto completion (Experimental)
+* History Reverse i-search
 * Work on Windows 10
 
 It doesn't support yet:
-* History reverse i-search
 * Customizable hotkeys
 * Unicode characters
 

src/char_reader.cr

@@ -19,6 +19,7 @@ module Reply
       CTRL_K
       CTRL_N
       CTRL_P
+      CTRL_R
       CTRL_U
       CTRL_X
       CTRL_UP
@@ -141,6 +142,8 @@ module Reply
         Sequence::CTRL_N
       when ctrl('p')
         Sequence::CTRL_P
+      when ctrl('r')
+        Sequence::CTRL_R
       when ctrl('u')
         Sequence::CTRL_U
       when ctrl('x')

src/expression_editor.cr

@@ -83,8 +83,10 @@ module Reply
 
     @scroll_offset = 0
     @header_height = 0
+    @footer_height = 0
 
     @header : IO, Int32 -> Int32 = ->(io : IO, previous_height : Int32) { 0 }
+    @footer : IO, Int32 -> Int32 = ->(io : IO, previous_height : Int32) { 0 }
     @highlight = ->(code : String) { code }
 
     # The list of characters delimiting words.
@@ -101,11 +103,19 @@ module Reply
     # Sets a `Proc` allowing to display a header above the prompt. (used by auto-completion)
     #
     # *io*: The IO in which the header should be displayed.
-    # *previous_hight*: Previous header height, useful to keep a header size constant.
+    # *previous_height*: Previous header height, useful to keep a header size constant.
     # Should returns the exact *height* printed in the io.
     def set_header(&@header : IO, Int32 -> Int32)
     end
 
+    # Sets a `Proc` allowing to display a footer under the prompt. (used by search)
+    #
+    # *io*: The IO in which the footer should be displayed.
+    # *previous_height*: Previous footer height.
+    # Should returns the exact *height* printed in the io.
+    def set_footer(&@footer : IO, Int32 -> Int32)
+    end
+
     # Sets the `Proc` to highlight the expression.
     def set_highlight(&@highlight : String -> String)
     end
@@ -383,7 +393,7 @@ module Reply
     #
     # The expression scrolls if it's higher than epression_max_height.
     private def epression_max_height
-      self.height - @header_height
+      self.height - @header_height - @footer_height
     end
 
     def move_cursor_left(allow_scrolling = true)
@@ -724,6 +734,13 @@ module Reply
       end
     end
 
+    # Calls the footer proc and saves the *footer_height*
+    private def update_footer : String
+      String.build do |io|
+        @footer_height = @footer.call(io, @footer_height)
+      end
+    end
+
     def replace(lines : Array(String))
       update { @lines = lines }
     end
@@ -873,6 +890,7 @@ module Reply
     private def print_expression_and_header(height_to_clear, force_full_view = false)
       height_to_clear += @header_height
       header = update_header()
+      footer = update_footer()
 
       if force_full_view
         start, end_ = 0, Int32::MAX
@@ -945,6 +963,17 @@ module Reply
         @output.print header
         @output.print display
 
+        if @footer_height != 0
+          # Display footer, then rewind cursor at the top left of the footer
+          @output.puts
+          @output.print footer
+          @output.print Term::Cursor.column(1)
+          move_real_cursor(x: @prompt_size, y: 1 - @footer_height)
+
+          cursor_move_y += 1
+          cursor_move_x = 0
+        end
+
         # Retrieve the real cursor at its corresponding cursor position (`@x`, `@y`)
         x_save, y_save = @x, @y
         @y = cursor_move_y

src/history.cr

@@ -2,12 +2,16 @@ module Reply
   class History
     getter history = Deque(Array(String)).new
     getter max_size = 10_000
-    @index = 0
+    getter index = 0
 
     # Hold the history lines being edited, always contains one element more than @history
     # because it can also contain the current line (not yet in history)
     @edited_history = [nil] of Array(String)?
 
+    def size
+      @history.size
+    end
+
     def <<(lines)
       lines = lines.dup # make history elements independent
 
@@ -45,8 +49,34 @@ module Reply
         @edited_history[@index] = current_edited_lines
 
         @index += 1
-        (@edited_history[@index]? || @history[@index]).dup
+        (@edited_history[@index]? || @history[@index]? || [""]).dup
+      end
+    end
+
+    def go_to(index)
+      if 0 <= index < @history.size
+        @index = index
+
+        @history[@index].dup
+      end
+    end
+
+    def search_up(query, from_index = @index - 1)
+      return nil, 0, 0 if query.empty?
+      return nil, 0, 0 unless 0 <= from_index < @history.size
+
+      # Search the history starting by `from_index` until first entry,
+      # then cycle the search by searching from last entry to `from_index`
+      from_index.downto(0).chain(
+        (@history.size - 1).downto(from_index + 1)
+      ).each do |i|
+        @history[i].each_with_index do |line, y|
+          x = line.index query
+          return i, x, y if x
+        end
       end
+
+      return nil, 0, 0
     end
 
     def max_size=(max_size)

src/reader.cr

@@ -2,6 +2,7 @@ require "./history"
 require "./expression_editor"
 require "./char_reader"
 require "./auto_completion"
+require "./search"
 
 module Reply
   # Reader for your REPL.
@@ -45,12 +46,14 @@ module Reply
     #                        ^    ^
     #                        |    |
     #                   History  AutoCompletion
+    #                   +Search
     # ```
 
     getter history = History.new
     getter editor : ExpressionEditor
     @auto_completion : AutoCompletion
     @char_reader = CharReader.new
+    @search = Search.new
     getter line_number = 1
 
     delegate :color?, :color=, :lines, :output, :output=, to: @editor
@@ -72,6 +75,10 @@ module Reply
         @auto_completion.display_entries(io, color?, max_height: {10, Term::Size.height - 1}.min, min_height: previous_height)
       end
 
+      @editor.set_footer do |io, _previous_height|
+        @search.footer(io, color?)
+      end
+
       @editor.set_highlight(&->highlight(String))
 
       if file = self.history_file
@@ -118,7 +125,7 @@ module Reply
       0
     end
 
-    # Override to select with expression is saved in history.
+    # Override to select which expression is saved in history.
     #
     # default: `!expression.blank?`
     def save_in_history?(expression : String)
@@ -132,6 +139,13 @@ module Reply
       nil
     end
 
+    # Override with `true` to disable the reverse i-search (ctrl-r).
+    #
+    # default: `true` (disabled) if `history_file` not set.
+    def disable_search?
+      history_file.nil?
+    end
+
     # Override to integrate auto-completion.
     #
     # *current_word* is picked following `word_delimiters`.
@@ -232,6 +246,7 @@ module Reply
         in .ctrl_delete?    then @editor.update { delete_word }
         in .alt_d?          then @editor.update { delete_word }
         in .ctrl_c?         then on_ctrl_c
+        in .ctrl_r?         then on_ctrl_r
         in .ctrl_d?
           if @editor.empty?
             output.puts
@@ -244,6 +259,12 @@ module Reply
           return nil
         end
 
+        if (read.is_a?(CharReader::Sequence) && (read.ctrl_r? || read.backspace?)) || read.is_a?(Char) || read.is_a?(String)
+        else
+          @search.close
+          @editor.update
+        end
+
         if read.is_a?(CharReader::Sequence) && (read.tab? || read.enter? || read.alt_enter? || read.shift_tab? || read.escape? || read.backspace? || read.ctrl_c?)
         else
           if @auto_completion.open?
@@ -278,6 +299,8 @@ module Reply
     end
 
     private def on_char(char)
+      return search_and_replace(@search.query + char) if @search.open?
+
       @editor.update do
         @editor << char
         line = @editor.current_line.rstrip(' ')
@@ -294,13 +317,21 @@ module Reply
     end
 
     private def on_string(string)
+      return search_and_replace(@search.query + string) if @search.open?
+
       @editor.update do
         @editor << string
       end
     end
 
     private def on_enter(alt_enter = false, ctrl_enter = false, &)
       @auto_completion.close
+      if @search.open?
+        @search.close
+        @editor.update
+        return
+      end
+
       if alt_enter || ctrl_enter || (@editor.cursor_on_last_line? && continue?(@editor.expression))
         @editor.update do
           insert_new_line(indent: self.indentation_level(@editor.expression_before_cursor))
@@ -338,6 +369,8 @@ module Reply
     end
 
     private def on_back
+      return search_and_replace(@search.query.rchop) if @search.open?
+
       auto_complete_remove_char if @auto_completion.open?
       @editor.update { back }
     end
@@ -365,12 +398,21 @@ module Reply
 
     private def on_ctrl_c
       @auto_completion.close
+      @search.close
       @editor.end_editing
       output.puts "^C"
       @history.set_to_last
       @editor.prompt_next
     end
 
+    private def on_ctrl_r
+      return if disable_search?
+
+      @auto_completion.close
+      @search.open
+      search_and_replace(reuse_index?: true)
+    end
+
     private def on_tab(shift_tab = false)
       if @auto_completion.open?
         if shift_tab
@@ -390,6 +432,7 @@ module Reply
 
     private def on_escape
       @auto_completion.close
+      @search.close
       @editor.update
     end
 
@@ -446,6 +489,16 @@ module Reply
       end
     end
 
+    private def search_and_replace(query = nil, reuse_index? = false)
+      @search.query = query if query
+
+      from_index = reuse_index? ? @history.index - 1 : @history.size - 1
+      result, x, y = @search.search(@history, from_index)
+      @editor.replace(result || [""])
+
+      @editor.move_cursor_to(x + @search.query.size, y) if result
+    end
+
     private def submit_expr(*, history = true)
       formated = format(@editor.expression).try &.split('\n')
       @editor.end_editing(replacement: formated)

src/search.cr

@@ -0,0 +1,39 @@
+module Reply
+  class Search
+    getter? open = false
+    property query = ""
+    getter? failed = false
+
+    def footer(io : IO, color? : Bool)
+      if open?
+        io << "search: #{@query.colorize.toggle(failed? && color?).bold.red}_"
+        1
+      else
+        0
+      end
+    end
+
+    def open
+      @open = true
+      @failed = false
+    end
+
+    def close
+      @open = false
+      @query = ""
+    end
+
+    def search(history, from_index = history.index)
+      index, x, y = history.search_up(@query, from_index: from_index)
+      if index
+        @failed = false
+        result = history.go_to index
+        return result, x, y
+      end
+
+      @failed = true
+      history.set_to_last
+      return nil, 0, 0
+    end
+  end
+end