Class: Lisp::PrimListSupport

Inherits:
Object
  • Object
show all
Defined in:
lib/rubylisp/prim_list_support.rb

Class Method Summary collapse

Class Method Details

.ad_impl(args, env, f) ⇒ Object

in support of all the CxR functions



130
131
132
133
134
 
# File 'lib/rubylisp/prim_list_support.rb', line 130

def self.ad_impl(args, env, f)
  l = args.car
  return Lisp::Debug.process_error("list required.", env) unless l.list?
  l.send(f)
end

.any_impl(args, env) ⇒ Object 



427
428
429
430
431
432
433
434
435
436
437
438
439
440
 
# File 'lib/rubylisp/prim_list_support.rb', line 427

def self.any_impl(args, env)
  p = args.car
  return Lisp::Debug.process_error("any requires a function as it's first argument", env) unless p.function? || p.primitive?
  lists = args.cdr.to_a
  return Lisp::Debug.process_error("any requires all subsequent arguments to be lists", env) unless lists.all? {|l| l.list?}

  while true
    cars = lists.collect {|l| l.nth(0)}
    return_val = p.apply_to(Lisp::ConsCell.array_to_list(cars), env)
    return Lisp::TRUE if return_val.value
    lists = lists.collect {|l| l.nth_tail(1)}
    return Lisp::FALSE if lists.any? {|l| l.empty?}
  end
end

.append_impl(args, env) ⇒ Object 



467
468
469
470
471
472
473
474
475
476
 
# File 'lib/rubylisp/prim_list_support.rb', line 467

def self.append_impl(args, env)
  l = args
  return Lisp::Debug.process_error("append requires lists", env) unless l.all? {|i| i.list? }
  new_items = []
  l.each do |sublist|
    sublist.each {|item| new_items << item.copy}
  end

  Lisp::ConsCell.array_to_list(new_items)
end

.appendbang_impl(args, env) ⇒ Object 



479
480
481
482
483
484
485
486
 
# File 'lib/rubylisp/prim_list_support.rb', line 479

def self.appendbang_impl(args, env)
  arg_array = args.to_a
  return Lisp::Debug.process_error("append! requires lists", env) unless arg_array.all? {|i| i.list?}
  (0...(arg_array.length-1)). each do |i|
    arg_array[i].last.set_cdr!(arg_array[i+1])
  end
  arg_array[0]
end

.cons_impl(args, env) ⇒ Object 



62
63
64
 
# File 'lib/rubylisp/prim_list_support.rb', line 62

def self.cons_impl(args, env)
  Lisp::ConsCell.cons(args.car, args.cadr)
end

.cons_star_impl(args, env) ⇒ Object 



67
68
69
70
71
 
# File 'lib/rubylisp/prim_list_support.rb', line 67

def self.cons_star_impl(args, env)
  return args.car if args.length == 1
  arg_ary = args.to_a
  Lisp::ConsCell::array_to_list(arg_ary[0..-2], arg_ary[-1])
end

.drop_impl(args, env) ⇒ Object 



286
287
288
289
290
291
292
293
 
# File 'lib/rubylisp/prim_list_support.rb', line 286

def self.drop_impl(args, env)
  k = args.car
  return Lisp::Debug.process_error("drop requires it's first argument to be an integer >= 0, but received #{l}", env) unless k.number? && k.value >= 0
  l = args.cadr
  return Lisp::Debug.process_error("drop requires it's second argument to be a list, but received #{l}", env) unless l.list?
  return Lisp::Debug.process_error("drop requires it's first argument to be <= the list length", env) unless k.value <= l.length
  l.nth_tail(k.value)
end

.eighth_impl(args, env) ⇒ Object 



199
200
201
202
203
204
 
# File 'lib/rubylisp/prim_list_support.rb', line 199

def self.eighth_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  return Lisp::Debug.process_error("list index out of bounds", env) unless l.length >= 8
  l.nth(7)
end

.every_impl(args, env) ⇒ Object 



443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
 
# File 'lib/rubylisp/prim_list_support.rb', line 443

def self.every_impl(args, env)
  p = args.car
  return Lisp::Debug.process_error("every requires a function as it's first argument", env) unless p.function? || p.primitive?
  lists = args.cdr.to_a
  return Lisp::Debug.process_error("every requires all subsequent arguments to be lists", env) unless lists.all? {|l| l.list?}

  
  while true
    cars = lists.collect {|l| l.nth(0)}
    return_val = p.apply_to(Lisp::ConsCell.array_to_list(cars), env)
    return Lisp::FALSE unless return_val.value
    lists = lists.collect {|l| l.nth_tail(1)}
    return Lisp::TRUE if lists.any? {|l| l.empty?}
  end
end

.fifth_impl(args, env) ⇒ Object 



175
176
177
178
179
180
 
# File 'lib/rubylisp/prim_list_support.rb', line 175

def self.fifth_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  return Lisp::Debug.process_error("list index out of bounds", env) unless l.length >= 5
  l.nth(4)
end

.filter_impl(args, env) ⇒ Object 



342
343
344
345
346
347
348
349
 
# File 'lib/rubylisp/prim_list_support.rb', line 342

def self.filter_impl(args, env)
  f = args.car
  return Lisp::Debug.process_error("filter requires a function as it's first argument but received #{args.car}.", env) unless f.function? || f.primitive?
  collection = args.cadr
  return Lisp::Debug.process_error("filter requires a list as it's second argument but received #{args.cadr}.", env) unless collection.list?
  results = collection.to_a.select {|item| f.apply_to_without_evaluating(Lisp::ConsCell.cons(item, nil), env).value }
  Lisp::ConsCell.array_to_list(results)
end

.first_impl(args, env) ⇒ Object 



137
138
139
140
141
142
 
# File 'lib/rubylisp/prim_list_support.rb', line 137

def self.first_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  return Lisp::Debug.process_error("list index out of bounds", env) unless l.length >= 1
  l.nth(0)
end

.flatten_impl(args, env) ⇒ Object 



489
490
491
492
493
 
# File 'lib/rubylisp/prim_list_support.rb', line 489

def self.flatten_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("flatten requires a list argument", env) unless l.list?
  l.flatten
end

.for_each_impl(args, env) ⇒ Object 



390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
 
# File 'lib/rubylisp/prim_list_support.rb', line 390

def self.for_each_impl(args, env)
  f = args.car
  return Lisp::Debug.process_error("for-each requires a function as it's first argument but received #{args.car}.", env) unless f.function? || f.primitive?
  collections = args.cdr
  return Lisp::Debug.process_error("for-each requires all subsequent arguments to be lists", env) unless collections.all? {|l| l.list?}
  lists = collections.collect {|l| l.to_a }
  
  map_args = []
  while (lists.all? {|l| !l.empty? })
    map_args << Lisp::ConsCell.array_to_list(lists.map {|l| l.shift })
  end
  map_args.collect {|item| f.apply_to_without_evaluating(item, env) }

  nil
end

.fourth_impl(args, env) ⇒ Object 



167
168
169
170
171
172
 
# File 'lib/rubylisp/prim_list_support.rb', line 167

def self.fourth_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  return Lisp::Debug.process_error("list index out of bounds", env) unless l.length >= 4
  l.nth(3)
end

.iota_impl(args, env) ⇒ Object 



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
 
# File 'lib/rubylisp/prim_list_support.rb', line 93

def self.iota_impl(args, env)
  arg1 = args.car
  return Lisp::Debug.process_error("iota requires an positive integer for it's first argument, received: #{arg1}", env) unless arg1.integer? && arg1.positive?
  count = arg1.value

  start = if args.length < 2
            0
          else
            arg2 = args.cadr
            return Lisp::Debug.process_error("iota requires an number for it's second argument, received: #{arg2}", env) unless arg2.number?
            arg2.value
          end

  step = if args.length < 3
            1
          else
            arg3 = args.caddr
            return Lisp::Debug.process_error("iota requires an number for it's third argument, received: #{arg3}", env) unless arg3.number?
            arg3.value
          end

  vals = []
  count.times do |c|
    vals << start
    start += step
  end

  Lisp::ConsCell::array_to_list(vals.map {|v| Number.with_value(v) })
end

.last_pair_impl(args, env) ⇒ Object 



296
297
298
299
300
 
# File 'lib/rubylisp/prim_list_support.rb', line 296

def self.last_pair_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("last_pair requires it's argument to be a list, but received #{l}", env) unless l.list?
  l.last
end

.length_impl(args, env) ⇒ Object 



124
125
126
 
# File 'lib/rubylisp/prim_list_support.rb', line 124

def self.length_impl(args, env)
  Lisp::Number.with_value(args.car.length)
end

.list_head_impl(args, env) ⇒ Object 



256
257
258
259
260
261
262
263
 
# File 'lib/rubylisp/prim_list_support.rb', line 256

def self.list_head_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("list_head requires it's first argument to be a list, but received #{l}", env) unless l.list?
  k = args.cadr
  return Lisp::Debug.process_error("list_head requires it's second argument to be a non-negative integer, but received #{k}", env) unless k.number? && k.value >= 0
  return Lisp::Debug.process_error("list_head requires it's second argument to be <= the list length", env) unless k.value <= l.length
  Lisp::ConsCell.array_to_list(l.to_a[0...k.value])
end

.list_impl(args, env) ⇒ Object 



74
75
76
 
# File 'lib/rubylisp/prim_list_support.rb', line 74

def self.list_impl(args, env)
  args
end

.list_tail_impl(args, env) ⇒ Object 



276
277
278
279
280
281
282
283
 
# File 'lib/rubylisp/prim_list_support.rb', line 276

def self.list_tail_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("list_head requires it's first argument to be a list, but received #{l}", env) unless l.list?
  k = args.cadr
  return Lisp::Debug.process_error("list_head requires it's second argument to be a non-negative integer, but received #{k}", env) unless k.number? && k.value >= 0
  return Lisp::Debug.process_error("list_head requires it's second argument to be <= the list length", env) unless k.value <= l.length
  l.nth_tail(k.value)
end

.make_list_impl(args, env) ⇒ Object 



79
80
81
82
83
84
85
86
87
88
89
90
 
# File 'lib/rubylisp/prim_list_support.rb', line 79

def self.make_list_impl(args, env)
  return Lisp::Debug.process_error("make-list requires an integer for it's first argument, received: #{args.car}", env) unless args.car.integer?
  count = args.car.value
  val = if args.length == 1
          nil
        else
          args.cadr
        end

  vals = Array.new(count, val)
  Lisp::ConsCell::array_to_list(vals)
end

.make_same_kind_as(sequence, value) ⇒ Object 



233
234
235
236
237
238
239
 
# File 'lib/rubylisp/prim_list_support.rb', line 233

def self.make_same_kind_as(sequence, value)
  if sequence.vector?
    Lisp::Vector.new(value)
  else
    Lisp::ConsCell.array_to_list(value)
  end
end

.map_impl(args, env) ⇒ Object 



374
375
376
377
378
379
380
381
382
383
384
385
386
387
 
# File 'lib/rubylisp/prim_list_support.rb', line 374

def self.map_impl(args, env)
  f = args.car
  return Lisp::Debug.process_error("map requires a function as it's first argument but received #{args.car}.", env) unless f.function? || f.primitive?
  collections = args.cdr.to_a
  return Lisp::Debug.process_error("map requires all subsequent arguments to be lists", env) unless collections.all? {|l| l.list?}
  lists = collections.collect {|l| l.to_a }
  
  map_args = []
  while (lists.all? {|l| !l.empty? })
    map_args << Lisp::ConsCell.array_to_list(lists.map {|l| l.shift })
  end
  results = map_args.collect {|item| f.apply_to_without_evaluating(item, env) }
  Lisp::ConsCell.array_to_list(results)
end

.member_impl(args, env) ⇒ Object 



329
330
331
332
333
334
335
336
337
338
339
 
# File 'lib/rubylisp/prim_list_support.rb', line 329

def self.member_impl(args, env)
  item = args.car
  collection = args.cadr
  return Lisp::Debug.process_error("member requires a list as it's second argument.", env) unless collection.list?
  collection.length.times do |i|
    if item.equal?(collection.nth(i))
      return collection.nth_tail(i)
    end
  end
  Lisp::FALSE
end

.memq_impl(args, env) ⇒ Object 



303
304
305
306
307
308
309
310
311
312
313
 
# File 'lib/rubylisp/prim_list_support.rb', line 303

def self.memq_impl(args, env)
  item = args.car
  collection = args.cadr
  return Lisp::Debug.process_error("memq requires a list as it's second argument.", env) unless collection.list?
  collection.length.times do |i|
    if item.eq?(collection.nth(i))
      return collection.nth_tail(i)
    end
  end
  Lisp::FALSE
end

.memv_impl(args, env) ⇒ Object 



316
317
318
319
320
321
322
323
324
325
326
 
# File 'lib/rubylisp/prim_list_support.rb', line 316

def self.memv_impl(args, env)
  item = args.car
  collection = args.cadr
  return Lisp::Debug.process_error("memv requires a list as it's second argument.", env) unless collection.list?
  collection.length.times do |i|
    if item.eqv?(collection.nth(i))
      return collection.nth_tail(i)
    end
  end
  Lisp::FALSE
end

.ninth_impl(args, env) ⇒ Object 



207
208
209
210
211
212
 
# File 'lib/rubylisp/prim_list_support.rb', line 207

def self.ninth_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  return Lisp::Debug.process_error("list index out of bounds", env) unless l.length >= 9
  l.nth(8)
end

.nth_impl(args, env) ⇒ Object 



223
224
225
226
227
228
229
230
 
# File 'lib/rubylisp/prim_list_support.rb', line 223

def self.nth_impl(args, env)
  n = args.car
  return Lisp::Debug.process_error("The first argument of nth has to be an number.", env) unless n.number?
  return Lisp::Debug.process_error("The first argument of nth has to be non-negative.", env) unless n.value >= 0
  l = args.cadr
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  l.nth(n.value)
end

.partition_impl(args, env) ⇒ Object 



362
363
364
365
366
367
368
369
370
371
 
# File 'lib/rubylisp/prim_list_support.rb', line 362

def self.partition_impl(args, env)
  f = args.car
  return Lisp::Debug.process_error("partition requires a function as it's first argument.", env) unless f.function? || f.primitive?
  collection = args.cadr
  return Lisp::Debug.process_error("partition requires a list as it's second argument.", env) unless collection.list?
  results = collection.to_a.partition {|item| f.apply_to_without_evaluating(Lisp::ConsCell.cons(item, nil), env).value }
  matches = Lisp::ConsCell.array_to_list(results[0])
  non_matches = Lisp::ConsCell.array_to_list(results[1])
  Lisp::ConsCell.array_to_list([matches, non_matches])
end

.quote_if_required(thing) ⇒ Object 



407
408
409
410
 
# File 'lib/rubylisp/prim_list_support.rb', line 407

def self.quote_if_required(thing)
  return thing unless thing.list? || thing.symbol?
  thing.quoted
end

.reduce_left_impl(args, env) ⇒ Object 



413
414
415
416
417
418
419
420
421
422
423
424
 
# File 'lib/rubylisp/prim_list_support.rb', line 413

def self.reduce_left_impl(args, env)
  f = args.car
  return Lisp::Debug.process_error("reduce-left requires a function as it's first argument but received #{args.car}.", env) unless f.function? || f.primitive?
  initial = args.cadr
  collection = args.caddr
  return Lisp::Debug.process_error("reduce-left requires a list as it's third argument but received #{args.caddr}.", env) unless collection.list?
  return initial if collection.empty?
  return collection.nth(0) if collection.length == 1
  collection.to_a.inject do |acc, item|
    f.apply_to_without_evaluating(Lisp::ConsCell.array_to_list([acc, item]), env)
  end
end

.register ⇒ Object 



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
 
# File 'lib/rubylisp/prim_list_support.rb', line 5

def self.register
  %w(car cdr caar cadr cdar cddr
     caaar caadr cadar caddr cdaar cdadr cddar cdddr
     caaaar caaadr caadar caaddr cadaar cadadr caddar cadddr
     cdaaar cdaadr cdadar cdaddr cddaar cddadr cdddar cddddr).each do |name|
    Primitive.register(name, "1")        {|args, env| ad_impl(args, env, name) }
  end

  Primitive.register("list", "*")        {|args, env|  Lisp::PrimListSupport::list_impl(args, env) }
  Primitive.register("cons*", "*")       {|args, env|  Lisp::PrimListSupport::cons_star_impl(args, env) }
  Primitive.register("cons", "2")        {|args, env|  Lisp::PrimListSupport::cons_impl(args, env) }
  Primitive.register("make-list", "1|2") {|args, env|  Lisp::PrimListSupport::make_list_impl(args, env) }
  Primitive.register("iota", "1|2|3")    {|args, env|  Lisp::PrimListSupport::iota_impl(args, env) }

  Primitive.register("length", "1")      {|args, env|  Lisp::PrimListSupport::length_impl(args, env) }
  Primitive.register("first", "1")       {|args, env|  Lisp::PrimListSupport::first_impl(args, env) }
  Primitive.register("head", "1")        {|args, env|  Lisp::PrimListSupport::first_impl(args, env) }
  Primitive.register("rest", "1")        {|args, env|  Lisp::PrimListSupport::rest_impl(args, env) }
  Primitive.register("tail", "1")        {|args, env|  Lisp::PrimListSupport::rest_impl(args, env) }
  Primitive.register("second", "1")      {|args, env|  Lisp::PrimListSupport::second_impl(args, env) }
  Primitive.register("third", "1")       {|args, env|  Lisp::PrimListSupport::third_impl(args, env) }
  Primitive.register("fourth", "1")      {|args, env|  Lisp::PrimListSupport::fourth_impl(args, env) }
  Primitive.register("fifth", "1")       {|args, env|  Lisp::PrimListSupport::fifth_impl(args, env) }
  Primitive.register("sixth", "1")       {|args, env|  Lisp::PrimListSupport::sixth_impl(args, env) }
  Primitive.register("seventh", "1")     {|args, env|  Lisp::PrimListSupport::seventh_impl(args, env) }
  Primitive.register("eighth", "1")      {|args, env|  Lisp::PrimListSupport::eighth_impl(args, env) }
  Primitive.register("ninth", "1")       {|args, env|  Lisp::PrimListSupport::ninth_impl(args, env) }
  Primitive.register("tenth", "1")       {|args, env|  Lisp::PrimListSupport::tenth_impl(args, env) }
  Primitive.register("nth", "2")         {|args, env|  Lisp::PrimListSupport::nth_impl(args, env) }

  Primitive.register("sublist", "3")     {|args, env|  Lisp::PrimListSupport::sublist_impl(args, env) }
  Primitive.register("list-head", "2")   {|args, env|  Lisp::PrimListSupport::list_head_impl(args, env) }
  Primitive.register("take", "2")        {|args, env|  Lisp::PrimListSupport::take_impl(args, env) }
  Primitive.register("list-tail", "2")   {|args, env|  Lisp::PrimListSupport::list_tail_impl(args, env) }
  Primitive.register("drop", "2")        {|args, env|  Lisp::PrimListSupport::drop_impl(args, env) }
  Primitive.register("last-pair", "1")   {|args, env|  Lisp::PrimListSupport::last_pair_impl(args, env) }

  Primitive.register("memq", "2")        {|args, env|  Lisp::PrimListSupport::memq_impl(args, env) }
  Primitive.register("memv", "2")        {|args, env|  Lisp::PrimListSupport::memv_impl(args, env) }
  Primitive.register("member", "2")      {|args, env|  Lisp::PrimListSupport::member_impl(args, env) }

  Primitive.register("filter", "2")      {|args, env| Lisp::PrimListSupport::filter_impl(args, env) }
  Primitive.register("remove", "2")      {|args, env| Lisp::PrimListSupport::remove_impl(args, env) }
  Primitive.register("partition", "2")   {|args, env| Lisp::PrimListSupport::partition_impl(args, env) }
  Primitive.register("map", ">=2")       {|args, env| Lisp::PrimListSupport::map_impl(args, env) }
  Primitive.register("for-each", ">=2")  {|args, env| Lisp::PrimListSupport::for_each_impl(args, env) }
  Primitive.register("reduce-left", "3") {|args, env| Lisp::PrimListSupport::reduce_left_impl(args, env) }
  Primitive.register("any", ">=2")       {|args, env| Lisp::PrimListSupport::any_impl(args, env) }
  Primitive.register("every", ">=2")     {|args, env| Lisp::PrimListSupport::every_impl(args, env) }
  Primitive.register("reverse", "1")     {|args, env| Lisp::PrimListSupport::reverse_impl(args, env) }
  Primitive.register("append", ">=1")    {|args, env| Lisp::PrimListSupport::append_impl(args, env) }
  Primitive.register("append!", ">=1")   {|args, env| Lisp::PrimListSupport::appendbang_impl(args, env) }
  Primitive.register("flatten", "1")     {|args, env| Lisp::PrimListSupport::flatten_impl(args, env) }
  # Primitive.register("flatten*")     {|args, env| Lisp::PrimListSupport::recursive_flatten_impl(args, env) }
end

.remove_impl(args, env) ⇒ Object 



352
353
354
355
356
357
358
359
 
# File 'lib/rubylisp/prim_list_support.rb', line 352

def self.remove_impl(args, env)
  f = args.car
  return Lisp::Debug.process_error("remove requires a function as it's first argument but received #{args.car}.", env) unless f.function? || f.primitive?
  collection = args.cadr
  return Lisp::Debug.process_error("remove requires a list as it's second argument but received #{args.cadr}.", env) unless collection.list?
  results = collection.to_a.reject {|item| f.apply_to_without_evaluating(Lisp::ConsCell.cons(item, nil), env).value }
  Lisp::ConsCell.array_to_list(results)
end

.rest_impl(args, env) ⇒ Object 



145
146
147
148
149
 
# File 'lib/rubylisp/prim_list_support.rb', line 145

def self.rest_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  l.cdr
end

.reverse_impl(args, env) ⇒ Object 



460
461
462
463
464
 
# File 'lib/rubylisp/prim_list_support.rb', line 460

def self.reverse_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("reverse requires a list", env) unless l.list?
  Lisp::ConsCell.array_to_list(l.to_a.reverse)
end

.second_impl(args, env) ⇒ Object 



152
153
154
155
156
157
 
# File 'lib/rubylisp/prim_list_support.rb', line 152

def self.second_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  return Lisp::Debug.process_error("list index out of bounds", env) unless l.length >= 2
  l.nth(1)
end

.seventh_impl(args, env) ⇒ Object 



191
192
193
194
195
196
 
# File 'lib/rubylisp/prim_list_support.rb', line 191

def self.seventh_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  return Lisp::Debug.process_error("list index out of bounds", env) unless l.length >= 7
  l.nth(6)
end

.sixth_impl(args, env) ⇒ Object 



183
184
185
186
187
188
 
# File 'lib/rubylisp/prim_list_support.rb', line 183

def self.sixth_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  return Lisp::Debug.process_error("list index out of bounds", env) unless l.length >= 6
  l.nth(5)
end

.sublist_impl(args, env) ⇒ Object 



242
243
244
245
246
247
248
249
250
251
252
253
 
# File 'lib/rubylisp/prim_list_support.rb', line 242

def self.sublist_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("sublist requires it's first argument to be a list, but received #{l}", env) unless l.list?
  st = args.cadr
  return Lisp::Debug.process_error("sublist requires it's second argument to be a non-negative integer, but received #{st}", env) unless st.number? && st.value >= 0
  return Lisp::Debug.process_error("sublist requires it's second argument to be <= the list length", env) unless st.value < l.length
  en = args.caddr
  return Lisp::Debug.process_error("sublist requires it's third argument to be a non-negative integer, but received #{en}", env) unless en.number? && en.value >= 0
  return Lisp::Debug.process_error("sublist requires it's third argument to be <= the list length", env) unless en.value < l.length
  return Lisp::Debug.process_error("sublist requires it's second argument to be <= the third argument", env) unless st.value <= en.value
  Lisp::ConsCell.array_to_list(l.to_a[st.value...en.value])
end

.take_impl(args, env) ⇒ Object 



266
267
268
269
270
271
272
273
 
# File 'lib/rubylisp/prim_list_support.rb', line 266

def self.take_impl(args, env)
  k = args.car
  return Lisp::Debug.process_error("take requires it's first argument to be a non-negative integer, but received #{k}", env) unless k.number? && k.value >= 0
  l = args.cadr
  return Lisp::Debug.process_error("take requires it's second argument to be a list, but received #{l}", env) unless l.list?
  return Lisp::Debug.process_error("take requires it's first argument to be <= the list length", env) unless k.value <= l.length
  Lisp::ConsCell.array_to_list(l.to_a[0...k.value])
end

.tenth_impl(args, env) ⇒ Object 



215
216
217
218
219
220
 
# File 'lib/rubylisp/prim_list_support.rb', line 215

def self.tenth_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  return Lisp::Debug.process_error("list index out of bounds", env) unless l.length >= 10
  l.nth(9)
end

.third_impl(args, env) ⇒ Object 



159
160
161
162
163
164
 
# File 'lib/rubylisp/prim_list_support.rb', line 159

def self.third_impl(args, env)
  l = args.car
  return Lisp::Debug.process_error("rest requires a list.", env) unless l.list?
  return Lisp::Debug.process_error("list index out of bounds", env) unless l.length >= 3
  l.nth(2)
end