Class: StackProf::Report

Inherits:
Object
  • Object
show all
Defined in:
lib/stackprof/report.rb

Defined Under Namespace

Classes: StackCursor

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ Report

Returns a new instance of Report.



8
9
10
# File 'lib/stackprof/report.rb', line 8

def initialize(data)
  @data = data
end

Instance Attribute Details

#dataObject (readonly)

Returns the value of attribute data.



11
12
13
# File 'lib/stackprof/report.rb', line 11

def data
  @data
end

Instance Method Details

#+(other) ⇒ Object

Raises:

  • (ArgumentError)


615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
# File 'lib/stackprof/report.rb', line 615

def +(other)
  raise ArgumentError, "cannot combine #{other.class}" unless self.class == other.class
  raise ArgumentError, "cannot combine #{modeline} with #{other.modeline}" unless modeline == other.modeline
  raise ArgumentError, "cannot combine v#{version} with v#{other.version}" unless version == other.version

  f1, f2 = normalized_frames, other.normalized_frames
  frames = (f1.keys + f2.keys).uniq.inject(Hash.new) do |hash, id|
    if f1[id].nil?
      hash[id] = f2[id]
    elsif f2[id]
      hash[id] = f1[id]
      hash[id][:total_samples] += f2[id][:total_samples]
      hash[id][:samples] += f2[id][:samples]
      if f2[id][:edges]
        edges = hash[id][:edges] ||= {}
        f2[id][:edges].each do |edge, weight|
          edges[edge] ||= 0
          edges[edge] += weight
        end
      end
      if f2[id][:lines]
        lines = hash[id][:lines] ||= {}
        f2[id][:lines].each do |line, weight|
          lines[line] = add_lines(lines[line], weight)
        end
      end
    else
      hash[id] = f1[id]
    end
    hash
  end

  d1, d2 = data, other.data
  data = {
    version: version,
    mode: d1[:mode],
    interval: d1[:interval],
    samples: d1[:samples] + d2[:samples],
    gc_samples: d1[:gc_samples] + d2[:gc_samples],
    missed_samples: d1[:missed_samples] + d2[:missed_samples],
    frames: frames
  }

  self.class.new(data)
end

#add_lines(a, b) ⇒ Object



58
59
60
61
62
63
# File 'lib/stackprof/report.rb', line 58

def add_lines(a, b)
  return b if a.nil?
  return a+b if a.is_a? Integer
  return [ a[0], a[1]+b ] if b.is_a? Integer
  [ a[0]+b[0], a[1]+b[1] ]
end

#convert_to_d3_flame_graph_format(name, stacks, depth) ⇒ Object



201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
# File 'lib/stackprof/report.rb', line 201

def convert_to_d3_flame_graph_format(name, stacks, depth)
  weight = 0
  children = []
  stacks.chunk do |stack|
    if depth == stack.length - 1
      :leaf
    else
      stack[depth]
    end
  end.each do |val, child_stacks|
    if val == :leaf
      child_stacks.each do |stack|
        weight += stack.last
      end
    else
      frame = @data[:frames][val]
      child_name = "#{ frame[:name] } : #{ frame[:file] }"
      child_data = convert_to_d3_flame_graph_format(child_name, child_stacks, depth + 1)
      weight += child_data["value"]
      children << child_data
    end
  end

  {
    "name" => name,
    "value" => weight,
    "children" => children,
  }
end

#filesObject



46
47
48
49
50
51
52
53
54
55
56
# File 'lib/stackprof/report.rb', line 46

def files
  @data[:files] ||= @data[:frames].inject(Hash.new) do |hash, (addr, frame)|
    if file = frame[:file] and lines = frame[:lines]
      hash[file] ||= Hash.new
      lines.each do |line, weight|
        hash[file][line] = add_lines(hash[file][line], weight)
      end
    end
    hash
  end
end

#flamegraph_row(f, x, y, weight, addr) ⇒ Object



194
195
196
197
198
199
# File 'lib/stackprof/report.rb', line 194

def flamegraph_row(f, x, y, weight, addr)
  frame = @data[:frames][addr]
  f.print ',' if @rows_started
  @rows_started = true
  f.puts %{{"x":#{x},"y":#{y},"width":#{weight},"frame_id":#{addr},"frame":#{frame[:name].dump},"file":#{frame[:file].dump}}}
end

#frames(sort_by_total = false) ⇒ Object



13
14
15
16
# File 'lib/stackprof/report.rb', line 13

def frames(sort_by_total=false)
  @data[:"sorted_frames_#{sort_by_total}"] ||=
    @data[:frames].sort_by{ |iseq, stats| -stats[sort_by_total ? :total_samples : :samples] }.inject({}){|h, (k, v)| h[k] = v; h}
end

#max_samplesObject



42
43
44
# File 'lib/stackprof/report.rb', line 42

def max_samples
  @data[:max_samples] ||= @data[:frames].values.max_by{ |frame| frame[:samples] }[:samples]
end

#modelineObject



34
35
36
# File 'lib/stackprof/report.rb', line 34

def modeline
  "#{@data[:mode]}(#{@data[:interval]})"
end

#normalized_framesObject



18
19
20
21
22
23
24
25
26
27
28
# File 'lib/stackprof/report.rb', line 18

def normalized_frames
  id2hash = {}
  @data[:frames].each do |frame, info|
    id2hash[frame.to_s] = info[:hash] = Digest::MD5.hexdigest("#{info[:name]}#{info[:file]}#{info[:line]}")
  end
  @data[:frames].inject(Hash.new) do |hash, (frame, info)|
    info = hash[id2hash[frame.to_s]] = info.dup
    info[:edges] = info[:edges].inject(Hash.new){ |edges, (edge, weight)| edges[id2hash[edge.to_s]] = weight; edges } if info[:edges]
    hash
  end
end

#overall_samplesObject



38
39
40
# File 'lib/stackprof/report.rb', line 38

def overall_samples
  @data[:samples]
end


94
95
96
# File 'lib/stackprof/report.rb', line 94

def print_alphabetical_flamegraph(f=STDOUT, skip_common=true)
  print_flamegraph(f, skip_common, true)
end


492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
# File 'lib/stackprof/report.rb', line 492

def print_callgrind(f = STDOUT)
  f.puts "version: 1"
  f.puts "creator: stackprof"
  f.puts "pid: 0"
  f.puts "cmd: ruby"
  f.puts "part: 1"
  f.puts "desc: mode: #{modeline}"
  f.puts "desc: missed: #{@data[:missed_samples]})"
  f.puts "positions: line"
  f.puts "events: Instructions"
  f.puts "summary: #{@data[:samples]}"

  list = frames
  list.each do |addr, frame|
    f.puts "fl=#{frame[:file]}"
    f.puts "fn=#{frame[:name]}"
    frame[:lines].each do |line, weight|
      f.puts "#{line} #{weight.is_a?(Array) ? weight[1] : weight}"
    end if frame[:lines]
    frame[:edges].each do |edge, weight|
      oframe = list[edge]
      f.puts "cfl=#{oframe[:file]}" unless oframe[:file] == frame[:file]
      f.puts "cfn=#{oframe[:name]}"
      f.puts "calls=#{weight} #{frame[:line] || 0}\n#{oframe[:line] || 0} #{weight}"
    end if frame[:edges]
    f.puts
  end

  f.puts "totals: #{@data[:samples]}"
end


231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
# File 'lib/stackprof/report.rb', line 231

def print_d3_flamegraph(f=STDOUT, skip_common=true)
  raise "profile does not include raw samples (add `raw: true` to collecting StackProf.run)" unless raw = data[:raw]

  stacks = []
  max_x = 0
  max_y = 0
  while len = raw.shift
    max_y = len if len > max_y
    stack = raw.slice!(0, len+1)
    stacks << stack
    max_x += stack.last
  end

  # d3-flame-grpah supports only alphabetical flamegraph
  stacks.sort!

  require "json"
  json = JSON.generate(convert_to_d3_flame_graph_format("<root>", stacks, 0), max_nesting: false)

  # This html code is almost copied from d3-flame-graph sample code.
  # (Apache License 2.0)
  # https://github.com/spiermar/d3-flame-graph/blob/gh-pages/index.html

  f.print <<-END
<!DOCTYPE html>
<html lang="en">
  <head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/spiermar/[email protected]/dist/d3-flamegraph.css">

<style>

/* Space out content a bit */
body {
  padding-top: 20px;
  padding-bottom: 20px;
}

/* Custom page header */
.header {
  padding-bottom: 20px;
  padding-right: 15px;
  padding-left: 15px;
  border-bottom: 1px solid #e5e5e5;
}

/* Make the masthead heading the same height as the navigation */
.header h3 {
  margin-top: 0;
  margin-bottom: 0;
  line-height: 40px;
}

/* Customize container */
.container {
  max-width: 990px;
}

address {
  text-align: right;
}
</style>

<title>stackprof (mode: #{ data[:mode] })</title>

<!-- HTML5 shim and Respond.js for IE8 support of HTML5 elements and media queries -->
<!--[if lt IE 9]>
  <script src="https://oss.maxcdn.com/html5shiv/3.7.2/html5shiv.min.js"></script>
  <script src="https://oss.maxcdn.com/respond/1.4.2/respond.min.js"></script>
<![endif]-->
  </head>
  <body>
<div class="container">
  <div class="header clearfix">
    <nav>
      <div class="pull-right">
        <form class="form-inline" id="form">
          <a class="btn" href="javascript: resetZoom();">Reset zoom</a>
          <a class="btn" href="javascript: clear();">Clear</a>
          <div class="form-group">
            <input type="text" class="form-control" id="term">
          </div>
          <a class="btn btn-primary" href="javascript: search();">Search</a>
        </form>
      </div>
    </nav>
    <h3 class="text-muted">stackprof (mode: #{ data[:mode] })</h3>
  </div>
  <div id="chart">
  </div>
  <address>
    powered by <a href="https://github.com/spiermar/d3-flame-graph">d3-flame-graph</a>
  </address>
  <hr>
  <div id="details">
  </div>
</div>

<!-- D3.js -->
<script src="https://d3js.org/d3.v4.min.js" charset="utf-8"></script>

<!-- d3-tip -->
<script type="text/javascript" src=https://cdnjs.cloudflare.com/ajax/libs/d3-tip/0.9.1/d3-tip.min.js></script>

<!-- d3-flamegraph -->
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/spiermar/[email protected]/dist/d3-flamegraph.min.js"></script>

<script type="text/javascript">
var flameGraph = d3.flamegraph()
  .width(960)
  .cellHeight(18)
  .transitionDuration(750)
  .minFrameSize(5)
  .transitionEase(d3.easeCubic)
  .sort(true)
  //Example to sort in reverse order
  //.sort(function(a,b){ return d3.descending(a.name, b.name);})
  .title("")
  .onClick(onClick)
  .differential(false)
  .selfValue(false);


// Example on how to use custom tooltips using d3-tip.
// var tip = d3.tip()
//   .direction("s")
//   .offset([8, 0])
//   .attr('class', 'd3-flame-graph-tip')
//   .html(function(d) { return "name: " + d.data.name + ", value: " + d.data.value; });

// flameGraph.tooltip(tip);

var details = document.getElementById("details");
flameGraph.setDetailsElement(details);

// Example on how to use custom labels
// var label = function(d) {
//  return "name: " + d.name + ", value: " + d.value;
// }
// flameGraph.label(label);

// Example of how to set fixed chart height
// flameGraph.height(540);

d3.select("#chart")
    .datum(#{ json })
    .call(flameGraph);

document.getElementById("form").addEventListener("submit", function(event){
  event.preventDefault();
  search();
});

function search() {
  var term = document.getElementById("term").value;
  flameGraph.search(term);
}

function clear() {
  document.getElementById('term').value = '';
  flameGraph.clear();
}

function resetZoom() {
  flameGraph.resetZoom();
}

function onClick(d) {
  console.info("Clicked on " + d.data.name);
}
</script>
  </body>
</html>
  END
end


65
66
67
# File 'lib/stackprof/report.rb', line 65

def print_debug
  pp @data
end


69
70
71
# File 'lib/stackprof/report.rb', line 69

def print_dump(f=STDOUT)
  f.puts Marshal.dump(@data.reject{|k,v| k == :files })
end


607
608
609
610
611
612
613
# File 'lib/stackprof/report.rb', line 607

def print_file(filter, f = STDOUT)
  filter = /#{Regexp.escape filter}/ unless Regexp === filter
  list = files.select{ |name, lines| name =~ filter }
  list.sort_by{ |file, vals| -vals.values.inject(0){ |sum, n| sum + (n.is_a?(Array) ? n[1] : n) } }.each do |file, lines|
    source_display(f, file, lines)
  end
end


597
598
599
600
601
602
603
604
605
# File 'lib/stackprof/report.rb', line 597

def print_files(sort_by_total=false, limit=nil, f = STDOUT)
  list = files.map{ |file, vals| [file, vals.values.inject([0,0]){ |sum, n| add_lines(sum, n) }] }
  list = list.sort_by{ |file, samples| -samples[1] }
  list = list.first(limit) if limit
  list.each do |file, vals|
    total_samples, samples = *vals
    f.printf "% 5d  (%5.1f%%) / % 5d  (%5.1f%%)   %s\n", total_samples, (100.0*total_samples/overall_samples), samples, (100.0*samples/overall_samples), file
  end
end


124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
# File 'lib/stackprof/report.rb', line 124

def print_flamegraph(f, skip_common, alphabetical=false)
  raise "profile does not include raw samples (add `raw: true` to collecting StackProf.run)" unless raw = data[:raw]

  stacks = []
  max_x = 0
  max_y = 0

  idx = 0
  loop do
    len = raw[idx]
    break unless len
    max_y = len if len > max_y

    stack = StackCursor.new(raw, idx, len)
    stacks << stack
    max_x += stack.weight

    idx += len + 2
  end

  stacks.sort! if alphabetical

  f.puts 'flamegraph(['
  max_y.times do |y|
    row_prev = nil
    row_width = 0
    x = 0

    stacks.each do |stack|
      weight = stack.weight
      cell = stack[y] unless y == stack.length-1

      if cell.nil?
        if row_prev
          flamegraph_row(f, x - row_width, y, row_width, row_prev)
        end

        row_prev = nil
        x += weight
        next
      end

      if row_prev.nil?        # start new row with this cell
        row_width = weight
        row_prev = cell
        x += weight

      elsif row_prev == cell  # grow current row along x-axis
        row_width += weight
        x += weight

      else                    # end current row and start new row
        flamegraph_row(f, x - row_width, y, row_width, row_prev)
        x += weight
        row_prev = cell
        row_width = weight
      end

      row_prev = cell
    end

    if row_prev
      next if skip_common && row_width == max_x

      flamegraph_row(f, x - row_width, y, row_width, row_prev)
    end
  end
  f.puts '])'
end


411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
# File 'lib/stackprof/report.rb', line 411

def print_graphviz(options = {}, f = STDOUT)
  if filter = options[:filter]
    mark_stack = []
    list = frames(true)
    list.each{ |addr, frame| mark_stack << addr if frame[:name] =~ filter }
    while addr = mark_stack.pop
      frame = list[addr]
      unless frame[:marked]
        mark_stack += frame[:edges].map{ |addr, weight| addr if list[addr][:total_samples] <= weight*1.2 }.compact if frame[:edges]
        frame[:marked] = true
      end
    end
    list = list.select{ |addr, frame| frame[:marked] }
    list.each{ |addr, frame| frame[:edges] && frame[:edges].delete_if{ |k,v| list[k].nil? } }
    list
  else
    list = frames(true)
  end


  limit = options[:limit]
  fraction = options[:node_fraction]

  included_nodes = {}
  node_minimum = fraction ? (fraction * overall_samples).ceil : 0

  f.puts "digraph profile {"
  f.puts "Legend [shape=box,fontsize=24,shape=plaintext,label=\""
  f.print "Total samples: #{overall_samples}\\l"
  f.print "Showing top #{limit} nodes\\l" if limit
  f.print "Dropped nodes with < #{node_minimum} samples\\l" if fraction
  f.puts "\"];"

  list.each_with_index do |(frame, info), index|
    call, total = info.values_at(:samples, :total_samples)
    break if total < node_minimum || (limit && index >= limit)

    sample = ''
    sample << "#{call} (%2.1f%%)\\rof " % (call*100.0/overall_samples) if call < total
    sample << "#{total} (%2.1f%%)\\r" % (total*100.0/overall_samples)
    fontsize = (1.0 * call / max_samples) * 28 + 10
    size = (1.0 * total / overall_samples) * 2.0 + 0.5

    f.puts "  \"#{frame}\" [size=#{size}] [fontsize=#{fontsize}] [penwidth=\"#{size}\"] [shape=box] [label=\"#{info[:name]}\\n#{sample}\"];"
    included_nodes[frame] = true
  end

  list.each do |frame, info|
    next unless included_nodes[frame]

    if edges = info[:edges]
      edges.each do |edge, weight|
        next unless included_nodes[edge]

        size = (1.0 * weight / overall_samples) * 2.0 + 0.5
        f.puts "  \"#{frame}\" -> \"#{edge}\" [label=\"#{weight}\"] [weight=\"#{weight}\"] [penwidth=\"#{size}\"];"
      end
    end
  end
  f.puts "}"
end


73
74
75
76
# File 'lib/stackprof/report.rb', line 73

def print_json(f=STDOUT)
  require "json"
  f.puts JSON.generate(@data, max_nesting: false)
end


523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
# File 'lib/stackprof/report.rb', line 523

def print_method(name, f = STDOUT)
  name = /#{name}/ unless Regexp === name
  frames.each do |frame, info|
    next unless info[:name] =~ name
    file, line = info.values_at(:file, :line)
    line ||= 1

    lines = info[:lines]
    maxline = lines ? lines.keys.max : line + 5
    f.printf "%s (%s:%d)\n", info[:name], file, line
    f.printf "  samples: % 5d self (%2.1f%%)  /  % 5d total (%2.1f%%)\n", info[:samples], 100.0*info[:samples]/overall_samples, info[:total_samples], 100.0*info[:total_samples]/overall_samples

    if (callers = callers_for(frame)).any?
      f.puts "  callers:"
      callers = callers.sort_by(&:last).reverse
      callers.each do |name, weight|
        f.printf "   % 5d  (% 8s)  %s\n", weight, "%3.1f%%" % (100.0*weight/info[:total_samples]), name
      end
    end

    if callees = info[:edges]
      f.printf "  callees (%d total):\n", info[:total_samples]-info[:samples]
      callees = callees.map{ |k, weight| [data[:frames][k][:name], weight] }.sort_by{ |k,v| -v }
      callees.each do |name, weight|
        f.printf "   % 5d  (% 8s)  %s\n", weight, "%3.1f%%" % (100.0*weight/(info[:total_samples]-info[:samples])), name
      end
    end

    f.puts "  code:"
    source_display(f, file, lines, line-1..maxline)
  end
end


78
79
80
81
82
83
84
85
86
87
88
# File 'lib/stackprof/report.rb', line 78

def print_stackcollapse
  raise "profile does not include raw samples (add `raw: true` to collecting StackProf.run)" unless raw = data[:raw]

  while len = raw.shift
    frames = raw.slice!(0, len)
    weight = raw.shift

    print frames.map{ |a| data[:frames][a][:name] }.join(';')
    puts " #{weight}"
  end
end


473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
# File 'lib/stackprof/report.rb', line 473

def print_text(sort_by_total=false, limit=nil, select_files= nil, reject_files=nil, select_names=nil, reject_names=nil, f = STDOUT)
  f.puts "=================================="
  f.printf "  Mode: #{modeline}\n"
  f.printf "  Samples: #{@data[:samples]} (%.2f%% miss rate)\n", 100.0*@data[:missed_samples]/(@data[:missed_samples]+@data[:samples])
  f.printf "  GC: #{@data[:gc_samples]} (%.2f%%)\n", 100.0*@data[:gc_samples]/@data[:samples]
  f.puts "=================================="
  f.printf "% 10s    (pct)  % 10s    (pct)     FRAME\n" % ["TOTAL", "SAMPLES"]
  list = frames(sort_by_total)
  list.select!{|_, info| select_files.any?{|path| info[:file].start_with?(path)}} if select_files
  list.select!{|_, info| select_names.any?{|reg| info[:name] =~ reg}} if select_names
  list.reject!{|_, info| reject_files.any?{|path| info[:file].start_with?(path)}} if reject_files
  list.reject!{|_, info| reject_names.any?{|reg| info[:name] =~ reg}} if reject_names
  list = list.first(limit) if limit
  list.each do |frame, info|
    call, total = info.values_at(:samples, :total_samples)
    f.printf "% 10d % 8s  % 10d % 8s     %s\n", total, "(%2.1f%%)" % (total*100.0/overall_samples), call, "(%2.1f%%)" % (call*100.0/overall_samples), info[:name]
  end
end


90
91
92
# File 'lib/stackprof/report.rb', line 90

def print_timeline_flamegraph(f=STDOUT, skip_common=true)
  print_flamegraph(f, skip_common, false)
end

#versionObject



30
31
32
# File 'lib/stackprof/report.rb', line 30

def version
  @data[:version]
end

#walk_method(name) ⇒ Object

Walk up and down the stack from a given starting point (name). Loops until ‘:exit` is selected



558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
# File 'lib/stackprof/report.rb', line 558

def walk_method(name)
  method_choice  = /#{Regexp.escape name}/
  invalid_choice = false

  # Continue walking up and down the stack until the users selects "exit"
  while method_choice != :exit
    print_method method_choice unless invalid_choice
    STDOUT.puts "\n\n"

    # Determine callers and callees for the current frame
    new_frames  = frames.select  {|_, info| info[:name] =~ method_choice }
    new_choices = new_frames.map {|frame, info| [
      callers_for(frame).sort_by(&:last).reverse.map(&:first),
      (info[:edges] || []).map{ |k, w| [data[:frames][k][:name], w] }.sort_by{ |k,v| -v }.map(&:first)
    ]}.flatten + [:exit]

    # Print callers and callees for selection
    STDOUT.puts "Select next method:"
    new_choices.each_with_index do |method, index|
      STDOUT.printf "%2d)  %s\n", index + 1, method.to_s
    end

    # Pick selection
    STDOUT.printf "> "
    selection = STDIN.gets.chomp.to_i - 1
    STDOUT.puts "\n\n\n"

    # Determine if it was a valid choice
    # (if not, don't re-run .print_method)
    if new_choice = new_choices[selection]
      invalid_choice = false
      method_choice = new_choice == :exit ? :exit : %r/^#{Regexp.escape new_choice}$/
    else
      invalid_choice = true
      STDOUT.puts "Invalid choice.  Please select again..."
    end
  end
end