feat: add configurable whitespace markers

src/ruby_config.rb

@@ -143,6 +143,7 @@ module Vamp
       @labels = {}
       @scroll_distance = 0
       @highlight_trailing_whitespace = false
+      @whitespace_characters = {}
       @diff_context_lines = 10
       @diff_expand_lines = 15
       @diff_view_mode = "split"
@@ -230,6 +231,19 @@ module Vamp
       @highlight_trailing_whitespace = enabled
     end
 
+    # @param characters [Hash{String => String}] whitespace character to single-cell marker
+    # @return [Hash{String => String}]
+    def whitespace_characters=(characters)
+      raise TypeError, "whitespace_characters must be a Hash" unless characters.is_a?(Hash)
+
+      characters.each do |whitespace, marker|
+        unless [whitespace, marker].all? { |value| value.is_a?(String) && value.length == 1 }
+          raise TypeError, "whitespace_characters keys and values must be single-character Strings"
+        end
+      end
+      @whitespace_characters = characters.dup
+    end
+
     # @param lines [Integer] nonnegative context lines around each diff change
     # @return [Integer]
     def diff_context_lines=(lines)
@@ -303,6 +317,7 @@ module Vamp
         "git_gutter" => @git_gutter,
         "scroll_distance" => @scroll_distance,
         "highlight_trailing_whitespace" => @highlight_trailing_whitespace,
+        "whitespace_characters" => @whitespace_characters,
         "top_bar" => @bar.top, "bottom_bar" => @bar.bottom, "labels" => @labels,
         "popup" => { "command" => @popup.command, "search" => @popup.search },
         "diff_context_lines" => @diff_context_lines, "diff_expand_lines" => @diff_expand_lines,