-
Notifications
You must be signed in to change notification settings - Fork 784
/
enumerator.rb
635 lines (604 loc) · 15.6 KB
/
enumerator.rb
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
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
193
194
195
196
197
198
199
200
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
230
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
410
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
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
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
522
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
555
556
557
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
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
##
# enumerator.rb Enumerator class
# See Copyright Notice in mruby.h
##
# A class which allows both internal and external iteration.
#
# An Enumerator can be created by the following methods.
# - {Kernel#to_enum}
# - {Kernel#enum_for}
# - {Enumerator#initialize Enumerator.new}
#
# Most methods have two forms: a block form where the contents
# are evaluated for each item in the enumeration, and a non-block form
# which returns a new Enumerator wrapping the iteration.
#
# enumerator = %w(one two three).each
# puts enumerator.class # => Enumerator
#
# enumerator.each_with_object("foo") do |item, obj|
# puts "#{obj}: #{item}"
# end
#
# # foo: one
# # foo: two
# # foo: three
#
# enum_with_obj = enumerator.each_with_object("foo")
# puts enum_with_obj.class # => Enumerator
#
# enum_with_obj.each do |item, obj|
# puts "#{obj}: #{item}"
# end
#
# # foo: one
# # foo: two
# # foo: three
#
# This allows you to chain Enumerators together. For example, you
# can map a list's elements to strings containing the index
# and the element as a string via:
#
# puts %w[foo bar baz].map.with_index { |w, i| "#{i}:#{w}" }
# # => ["0:foo", "1:bar", "2:baz"]
#
# An Enumerator can also be used as an external iterator.
# For example, Enumerator#next returns the next value of the iterator
# or raises StopIteration if the Enumerator is at the end.
#
# e = [1,2,3].each # returns an enumerator object.
# puts e.next # => 1
# puts e.next # => 2
# puts e.next # => 3
# puts e.next # raises StopIteration
#
# You can use this to implement an internal iterator as follows:
#
# def ext_each(e)
# while true
# begin
# vs = e.next_values
# rescue StopIteration
# return $!.result
# end
# y = yield(*vs)
# e.feed y
# end
# end
#
# o = Object.new
#
# def o.each
# puts yield
# puts yield(1)
# puts yield(1, 2)
# 3
# end
#
# # use o.each as an internal iterator directly.
# puts o.each {|*x| puts x; [:b, *x] }
# # => [], [:b], [1], [:b, 1], [1, 2], [:b, 1, 2], 3
#
# # convert o.each to an external iterator for
# # implementing an internal iterator.
# puts ext_each(o.to_enum) {|*x| puts x; [:b, *x] }
# # => [], [:b], [1], [:b, 1], [1, 2], [:b, 1, 2], 3
#
class Enumerator
include Enumerable
##
# @overload initialize(size = nil, &block)
# @overload initialize(obj, method = :each, *args)
#
# Creates a new Enumerator object, which can be used as an
# Enumerable.
#
# In the first form, iteration is defined by the given block, in
# which a "yielder" object, given as block parameter, can be used to
# yield a value by calling the +yield+ method (aliased as +<<+):
#
# fib = Enumerator.new do |y|
# a = b = 1
# loop do
# y << a
# a, b = b, a + b
# end
# end
#
# p fib.take(10) # => [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
#
def initialize(obj=nil, meth=:each, *args, &block)
if block_given?
obj = Generator.new(&block)
else
raise ArgumentError unless obj
end
@obj = obj
@meth = meth
@args = args.dup
@fib = nil
@dst = nil
@lookahead = nil
@feedvalue = nil
@stop_exc = false
end
attr_accessor :obj, :meth, :args, :fib
private :obj, :meth, :args, :fib
def initialize_copy(obj)
raise TypeError, "can't copy type #{obj.class}" unless obj.kind_of? Enumerator
raise TypeError, "can't copy execution context" if obj.fib
@obj = obj.obj
@meth = obj.meth
@args = obj.args
@fib = nil
@lookahead = nil
@feedvalue = nil
self
end
##
# call-seq:
# e.with_index(offset = 0) {|(*args), idx| ... }
# e.with_index(offset = 0)
#
# Iterates the given block for each element with an index, which
# starts from +offset+. If no block is given, returns a new Enumerator
# that includes the index, starting from +offset+
#
# +offset+:: the starting index to use
#
def with_index(offset=0)
return to_enum :with_index, offset unless block_given?
raise TypeError, "no implicit conversion of #{offset.class} into Integer" unless offset.respond_to?(:to_int)
n = offset.to_int - 1
enumerator_block_call do |i|
n += 1
yield [i,n]
end
end
##
# call-seq:
# e.each_with_index {|(*args), idx| ... }
# e.each_with_index
#
# Same as Enumerator#with_index(0), i.e. there is no starting offset.
#
# If no block is given, a new Enumerator is returned that includes the index.
#
def each_with_index
with_index
end
##
# call-seq:
# e.each_with_object(obj) {|(*args), obj| ... }
# e.each_with_object(obj)
# e.with_object(obj) {|(*args), obj| ... }
# e.with_object(obj)
#
# Iterates the given block for each element with an arbitrary object, +obj+,
# and returns +obj+
#
# If no block is given, returns a new Enumerator.
#
# @example
# to_three = Enumerator.new do |y|
# 3.times do |x|
# y << x
# end
# end
#
# to_three_with_string = to_three.with_object("foo")
# to_three_with_string.each do |x,string|
# puts "#{string}: #{x}"
# end
#
# # => foo:0
# # => foo:1
# # => foo:2
#
def with_object(object)
return to_enum(:with_object, object) unless block_given?
enumerator_block_call do |i|
yield [i,object]
end
object
end
def inspect
return "#<#{self.class}: uninitialized>" unless @obj
if @args && @args.size > 0
args = @args.join(", ")
"#<#{self.class}: #{@obj}:#{@meth}(#{args})>"
else
"#<#{self.class}: #{@obj}:#{@meth}>"
end
end
##
# call-seq:
# enum.each { |elm| block } -> obj
# enum.each -> enum
# enum.each(*appending_args) { |elm| block } -> obj
# enum.each(*appending_args) -> an_enumerator
#
# Iterates over the block according to how this Enumerator was constructed.
# If no block and no arguments are given, returns self.
#
# === Examples
#
# "Hello, world!".scan(/\w+/) #=> ["Hello", "world"]
# "Hello, world!".to_enum(:scan, /\w+/).to_a #=> ["Hello", "world"]
# "Hello, world!".to_enum(:scan).each(/\w+/).to_a #=> ["Hello", "world"]
#
# obj = Object.new
#
# def obj.each_arg(a, b=:b, *rest)
# yield a
# yield b
# yield rest
# :method_returned
# end
#
# enum = obj.to_enum :each_arg, :a, :x
#
# enum.each.to_a #=> [:a, :x, []]
# enum.each.equal?(enum) #=> true
# enum.each { |elm| elm } #=> :method_returned
#
# enum.each(:y, :z).to_a #=> [:a, :x, [:y, :z]]
# enum.each(:y, :z).equal?(enum) #=> false
# enum.each(:y, :z) { |elm| elm } #=> :method_returned
#
def each(*argv, &block)
obj = self
if 0 < argv.length
obj = self.dup
args = obj.args
if !args.empty?
args = args.dup
args.concat argv
else
args = argv.dup
end
obj.args = args
end
return obj unless block_given?
enumerator_block_call(&block)
end
def enumerator_block_call(&block)
@obj.__send__ @meth, *@args, &block
end
private :enumerator_block_call
##
# call-seq:
# e.next -> object
#
# Returns the next object in the enumerator, and move the internal position
# forward. When the position reached at the end, StopIteration is raised.
#
# === Example
#
# a = [1,2,3]
# e = a.to_enum
# p e.next #=> 1
# p e.next #=> 2
# p e.next #=> 3
# p e.next #raises StopIteration
#
# Note that enumeration sequence by +next+ does not affect other non-external
# enumeration methods, unless the underlying iteration methods itself has
# side-effect
#
def next
next_values.__svalue
end
##
# call-seq:
# e.next_values -> array
#
# Returns the next object as an array in the enumerator, and move the
# internal position forward. When the position reached at the end,
# StopIteration is raised.
#
# This method can be used to distinguish <code>yield</code> and <code>yield
# nil</code>.
#
# === Example
#
# o = Object.new
# def o.each
# yield
# yield 1
# yield 1, 2
# yield nil
# yield [1, 2]
# end
# e = o.to_enum
# p e.next_values
# p e.next_values
# p e.next_values
# p e.next_values
# p e.next_values
# e = o.to_enum
# p e.next
# p e.next
# p e.next
# p e.next
# p e.next
#
# ## yield args next_values next
# # yield [] nil
# # yield 1 [1] 1
# # yield 1, 2 [1, 2] [1, 2]
# # yield nil [nil] nil
# # yield [1, 2] [[1, 2]] [1, 2]
#
# Note that +next_values+ does not affect other non-external enumeration
# methods unless underlying iteration method itself has side-effect
#
def next_values
if @lookahead
vs = @lookahead
@lookahead = nil
return vs
end
raise @stop_exc if @stop_exc
curr = Fiber.current
if !@fib || !@fib.alive?
@dst = curr
@fib = Fiber.new do
result = each do |*args|
feedvalue = nil
Fiber.yield args
if @feedvalue
feedvalue = @feedvalue
@feedvalue = nil
end
feedvalue
end
@stop_exc = StopIteration.new "iteration reached an end"
@stop_exc.result = result
Fiber.yield nil
end
@lookahead = nil
end
vs = @fib.resume curr
if @stop_exc
@fib = nil
@dst = nil
@lookahead = nil
@feedvalue = nil
raise @stop_exc
end
vs
end
##
# call-seq:
# e.peek -> object
#
# Returns the next object in the enumerator, but doesn't move the internal
# position forward. If the position is already at the end, StopIteration
# is raised.
#
# === Example
#
# a = [1,2,3]
# e = a.to_enum
# p e.next #=> 1
# p e.peek #=> 2
# p e.peek #=> 2
# p e.peek #=> 2
# p e.next #=> 2
# p e.next #=> 3
# p e.next #raises StopIteration
#
def peek
peek_values.__svalue
end
##
# call-seq:
# e.peek_values -> array
#
# Returns the next object as an array, similar to Enumerator#next_values, but
# doesn't move the internal position forward. If the position is already at
# the end, StopIteration is raised.
#
# === Example
#
# o = Object.new
# def o.each
# yield
# yield 1
# yield 1, 2
# end
# e = o.to_enum
# p e.peek_values #=> []
# e.next
# p e.peek_values #=> [1]
# p e.peek_values #=> [1]
# e.next
# p e.peek_values #=> [1, 2]
# e.next
# p e.peek_values # raises StopIteration
#
def peek_values
if @lookahead.nil?
@lookahead = next_values
end
@lookahead.dup
end
##
# call-seq:
# e.rewind -> e
#
# Rewinds the enumeration sequence to the beginning.
#
# If the enclosed object responds to a "rewind" method, it is called.
#
def rewind
@obj.rewind if @obj.respond_to? :rewind
@fib = nil
@dst = nil
@lookahead = nil
@feedvalue = nil
@stop_exc = false
self
end
##
# call-seq:
# e.feed obj -> nil
#
# Sets the value to be returned by the next yield inside +e+.
#
# If the value is not set, the yield returns nil.
#
# This value is cleared after being yielded.
#
# # Array#map passes the array's elements to "yield" and collects the
# # results of "yield" as an array.
# # Following example shows that "next" returns the passed elements and
# # values passed to "feed" are collected as an array which can be
# # obtained by StopIteration#result.
# e = [1,2,3].map
# p e.next #=> 1
# e.feed "a"
# p e.next #=> 2
# e.feed "b"
# p e.next #=> 3
# e.feed "c"
# begin
# e.next
# rescue StopIteration
# p $!.result #=> ["a", "b", "c"]
# end
#
# o = Object.new
# def o.each
# x = yield # (2) blocks
# p x # (5) => "foo"
# x = yield # (6) blocks
# p x # (8) => nil
# x = yield # (9) blocks
# p x # not reached w/o another e.next
# end
#
# e = o.to_enum
# e.next # (1)
# e.feed "foo" # (3)
# e.next # (4)
# e.next # (7)
# # (10)
#
def feed(value)
raise TypeError, "feed value already set" if @feedvalue
@feedvalue = value
nil
end
# just for internal
class Generator
include Enumerable
def initialize(&block)
raise TypeError, "wrong argument type #{self.class} (expected Proc)" unless block.kind_of? Proc
@proc = block
end
def each(*args, &block)
args.unshift Yielder.new(&block)
@proc.call(*args)
end
end
# just for internal
class Yielder
def initialize(&block)
raise LocalJumpError, "no block given" unless block_given?
@proc = block
end
def yield(*args)
@proc.call(*args)
end
def << *args
self.yield(*args)
self
end
end
end
module Kernel
##
# call-seq:
# obj.to_enum(method = :each, *args) -> enum
# obj.enum_for(method = :each, *args) -> enum
# obj.to_enum(method = :each, *args) {|*args| block} -> enum
# obj.enum_for(method = :each, *args){|*args| block} -> enum
#
# Creates a new Enumerator which will enumerate by calling +method+ on
# +obj+, passing +args+ if any.
#
# If a block is given, it will be used to calculate the size of
# the enumerator without the need to iterate it (see Enumerator#size).
#
# === Examples
#
# str = "xyz"
#
# enum = str.enum_for(:each_byte)
# enum.each { |b| puts b }
# # => 120
# # => 121
# # => 122
#
# # protect an array from being modified by some_method
# a = [1, 2, 3]
# some_method(a.to_enum)
#
# It is typical to call to_enum when defining methods for
# a generic Enumerable, in case no block is passed.
#
# Here is such an example, with parameter passing and a sizing block:
#
# module Enumerable
# # a generic method to repeat the values of any enumerable
# def repeat(n)
# raise ArgumentError, "#{n} is negative!" if n < 0
# unless block_given?
# return to_enum(__method__, n) do # __method__ is :repeat here
# sz = size # Call size and multiply by n...
# sz * n if sz # but return nil if size itself is nil
# end
# end
# each do |*val|
# n.times { yield *val }
# end
# end
# end
#
# %i[hello world].repeat(2) { |w| puts w }
# # => Prints 'hello', 'hello', 'world', 'world'
# enum = (1..14).repeat(3)
# # => returns an Enumerator when called without a block
# enum.first(4) # => [1, 1, 1, 2]
#
def to_enum(meth=:each, *args)
Enumerator.new self, meth, *args
end
alias :enum_for :to_enum
end
module Enumerable
# use Enumerator to use infinite sequence
def zip(*arg)
ary = []
arg = arg.map{|a|a.each}
i = 0
self.each do |*val|
a = []
a.push(val.__svalue)
idx = 0
while idx < arg.size
begin
a.push(arg[idx].next)
rescue StopIteration
a.push(nil)
end
idx += 1
end
ary.push(a)
i += 1
end
ary
end
end