class PM::Cursor

A PM::Cursor knows the current PM::SongList, PM::Song, and PM::Patch, how to move between songs and patches, and how to find them given name regexes.

Attributes

patch[R]
song[R]
song_list[R]

Public Class Methods

new(pm) click to toggle source
# File lib/patchmaster/cursor.rb, line 10
def initialize(pm)
  @pm = pm
  clear
end

Public Instance Methods

clear() click to toggle source

Set @song_list, @song, and @patch to nil.

# File lib/patchmaster/cursor.rb, line 16
def clear
  @song_list = @song = @patch = nil
  # Do not erase names saved by #mark.
end
dameraulevenshtein(seq1, seq2) click to toggle source

gist.github.com/182759 (git://gist.github.com/182759.git) Referenced from en.wikipedia.org/wiki/Damerau%E2%80%93Levenshtein_distance

# File lib/patchmaster/cursor.rb, line 154
def dameraulevenshtein(seq1, seq2)
  oneago = nil
  thisrow = (1..seq2.size).to_a + [0]
  seq1.size.times do |x|
    twoago, oneago, thisrow = oneago, thisrow, [0] * seq2.size + [x + 1]
    seq2.size.times do |y|
      delcost = oneago[y] + 1
      addcost = thisrow[y - 1] + 1
      subcost = oneago[y - 1] + ((seq1[x] != seq2[y]) ? 1 : 0)
      thisrow[y] = [delcost, addcost, subcost].min
      if (x > 0 and y > 0 and seq1[x] == seq2[y-1] and seq1[x-1] == seq2[y] and seq1[x] != seq2[y])
        thisrow[y] = [thisrow[y], twoago[y-2] + 1].min
      end
    end
  end
  return thisrow[seq2.size - 1]
end
find_nearest_match(list, str) click to toggle source

List must contain objects that respond to name. If str is nil or list is nil or empty then nil is returned.

# File lib/patchmaster/cursor.rb, line 144
def find_nearest_match(list, str)
  return nil unless str && list && !list.empty?

  str = str.downcase
  distances = list.collect { |item| dameraulevenshtein(str, item.name.downcase) }
  list[distances.index(distances.min)]
end
goto_song(name_regex) click to toggle source
# File lib/patchmaster/cursor.rb, line 75
def goto_song(name_regex)
  new_song_list = new_song = new_patch = nil
  new_song = @song_list.find(name_regex) if @song_list
  new_song = @@pm.all_songs.find(name_regex) unless new_song
  new_patch = new_song ? new_song.patches.first : nil

  if (new_song && new_song != @song) || # moved to new song
      (new_song == @song && @patch != new_patch) # same song but not at same first patch

    @patch.stop if @patch

    if @song_list.songs.include?(new_song)
      new_song_list = @song_list
    else
      # Not found in current song list. Switch to @pm.all_songs list.
      new_song_list = @@pm.all_songs
    end

    @song_list = new_song_list
    @song = new_song
    @patch = new_patch
    @patch.start
  end
end
goto_song_list(name_regex) click to toggle source
# File lib/patchmaster/cursor.rb, line 100
def goto_song_list(name_regex)
  name_regex = Regexp.new(name_regex.to_s, true) # make case-insensitive
  new_song_list = @pm.song_lists.detect { |song_list| song_list.name =~ name_regex }
  return unless new_song_list

  @song_list = new_song_list

  new_song = @song_list.songs.first
  new_patch = new_song ? new_song.patches.first : nil

  if new_patch != @patch
    @patch.stop if @patch
    new_patch.start if new_patch
  end
  @song = new_song
  @patch = new_patch
end
init() click to toggle source

Set @song_list to All Songs, @song to first song, and @patch to song's first patch. Song and patch may be nil.

# File lib/patchmaster/cursor.rb, line 23
def init
  @song_list = @pm.song_lists.first
  @song = @song_list.songs.first
  if @song
    @patch = @song.patches.first
  else
    @patch = nil
  end
end
mark() click to toggle source

Remembers the names of the current song list, song, and patch. Used by restore.

# File lib/patchmaster/cursor.rb, line 120
def mark
  @song_list_name = @song_list ? @song_list.name : nil
  @song_name = @song ? @song.name : nil
  @patch_name = @patch ? @patch.name : nil
end
next_patch() click to toggle source
# File lib/patchmaster/cursor.rb, line 53
def next_patch
  return unless @song
  if @song.patches.last == @patch
    next_song
  elsif @patch
    @patch.stop
    @patch = @song.patches[@song.patches.index(@patch) + 1]
    @patch.start
  end
end
next_song() click to toggle source
# File lib/patchmaster/cursor.rb, line 33
def next_song
  return unless @song_list
  return if @song_list.songs.last == @song

  @patch.stop if @patch
  @song = @song_list.songs[@song_list.songs.index(@song) + 1]
  @patch = @song.patches.first
  @patch.start
end
prev_patch() click to toggle source
# File lib/patchmaster/cursor.rb, line 64
def prev_patch
  return unless @song
  if @song.patches.first == @patch
    prev_song
  elsif @patch
    @patch.stop
    @patch = @song.patches[@song.patches.index(@patch) - 1]
    @patch.start
  end
end
prev_song() click to toggle source
# File lib/patchmaster/cursor.rb, line 43
def prev_song
  return unless @song_list
  return if @song_list.songs.first == @song

  @patch.stop if @patch
  @song = @song_list.songs[@song_list.songs.index(@song) - 1]
  @patch = @song.patches.first
  @patch.start
end
restore() click to toggle source

Using the names saved by save, try to find them now.

Since names can change we use Damerau-Levenshtein distance on lowercase versions of all strings.

# File lib/patchmaster/cursor.rb, line 130
def restore
  return unless @song_list_name   # will be nil on initial load

  @song_list = find_nearest_match(@pm.song_lists, @song_list_name) || @pm.all_songs
  @song = find_nearest_match(@song_list.songs, @song_name) || @song_list.songs.first
  if @song
    @patch = find_nearest_match(@song.patches, @patch_name) || @song.patches.first
  else
    @patch = nil
  end
end