Module: Canon::DiffFormatter::Legend

Defined in:
lib/canon/diff_formatter/legend.rb

Overview

Module for building Unicode character visualization legends

Class Method Summary collapse

Class Method Details

.build_diff_symbol_legend(use_color: true) ⇒ String

Build diff symbol legend

Parameters:

  • use_color (Boolean) (defaults to: true) —

    Whether to use colors

Returns:

  • (String) —

    Formatted diff symbol legend



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# File 'lib/canon/diff_formatter/legend.rb', line 106

def self.build_diff_symbol_legend(use_color: true)
  output = []
  separator = "━" * 60

  output << colorize("Diff Symbol Legend:", :cyan, :bold, use_color)
  output << colorize(separator, :cyan, :bold, use_color)

  # Formatting-only changes
  output << colorize("Formatting Changes (cosmetic only):", :yellow,
                     :bold, use_color)
  output << "  #{colorize('[', :black, :bold,
                          use_color)}: Line removed (formatting only - dark gray)"
  output << "  #{colorize(']', :white, :bold,
                          use_color)}: Line added (formatting only - light gray)"
  output << ""

  # Informative changes
  output << colorize("Informative Changes (do not affect equivalence):",
                     :yellow, :bold, use_color)
  output << "  #{colorize('<', :blue, :bold,
                          use_color)}: Line removed (informative - blue)"
  output << "  #{colorize('>', :cyan, :bold,
                          use_color)}: Line added (informative - cyan)"
  output << ""

  # Normative changes
  output << colorize("Normative Changes (affect equivalence):", :yellow,
                     :bold, use_color)
  output << "  #{colorize('-', :red, :bold,
                          use_color)}: Line removed (normative difference - red)"
  output << "  #{colorize('+', :green, :bold,
                          use_color)}: Line added (normative difference - green)"
  output << ""

  output << colorize(separator, :cyan, :bold, use_color)
  output.join("\n")
end

.build_legend(detected_chars, use_color: true) ⇒ String?

Build formatted legend from detected characters

Parameters:

  • detected_chars (Hash) —

    Hash from detect_non_ascii

  • use_color (Boolean) (defaults to: true) —

    Whether to use colors

Returns:

  • (String, nil) —

    Formatted legend or nil if no characters



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# File 'lib/canon/diff_formatter/legend.rb', line 62

def self.build_legend(detected_chars, use_color: true)
  return nil if detected_chars.empty?

  # Group characters by category
  grouped = detected_chars.group_by { |_char, info| info[:category] }

  output = []
  separator = "━" * 60

  output << colorize("Character Visualization Legend:", :cyan, :bold,
                     use_color)
  output << colorize(separator, :cyan, :bold, use_color)

  # Display each category
  category_names = DiffFormatter::CHARACTER_CATEGORY_NAMES
  category_names.each do |category_key, category_name|
    chars = grouped[category_key]
    next unless chars

    output << colorize("#{category_name}:", :yellow, :bold, use_color)

    chars.sort_by { |char, _info| char.ord }.each do |char, info|
      # Format: '⏓': U+2005 (' ') Four-Per-Em Space
      vis = info[:visualization]
      code = info[:codepoint]
      name = format_name(info[:name])

      # Show original character in quotes, handling special cases
      original = format_original_char(char)

      line = "  '#{vis}': #{code} ('#{original}') #{name}"
      output << (use_color ? line : line)
    end
    output << ""
  end

  output << colorize(separator, :cyan, :bold, use_color)
  output.join("\n")
end

.detect_non_ascii(text, visualization_map) ⇒ Hash

Detect non-ASCII characters in text and return their information

Parameters:

  • text (String) —

    Text to analyze

  • visualization_map (Hash) —

    Character visualization map

Returns:

  • (Hash) —

    Hash of characters with their metadata



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# File 'lib/canon/diff_formatter/legend.rb', line 14

def self.detect_non_ascii(text, visualization_map)
  # each_char allocates a 1-char String per character — over two
  # full documents per render that is the presentation stage's
  # biggest allocation source. ASCII-only text (the common case)
  # needs no scan at all; otherwise scan codepoints and
  # materialize the character String only at non-ASCII offsets.
  return {} if text.ascii_only?

  detected = {}
  category_map = DiffFormatter::CHARACTER_CATEGORY_MAP
  metadata = DiffFormatter::CHARACTER_METADATA

  index = -1
  text.each_codepoint do |codepoint|
    index += 1
    next if codepoint <= 127

    char = text[index, 1]
    next if detected.key?(char)

    visualization = visualization_map.fetch(char, char)
    next if visualization == char # Skip if no visualization mapping

    codepoint = format("U+%04X", char.ord)

    # Use name from metadata if available, otherwise use Unicode::Name
    name = if metadata[char] && metadata[char][:name]
             metadata[char][:name]
           else
             Unicode::Name.of(char) || "UNKNOWN"
           end

    detected[char] = {
      visualization: visualization,
      codepoint: codepoint,
      name: name,
      category: category_map.fetch(char, :control),
    }
  end

  detected
end