Class: Lisp::ListSupport

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

Class Method Summary collapse

Class Method Details

.ad_impl(args, env, f) ⇒ Object

in support of all the CxR functions



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# File 'lib/rubylisp/list_support.rb', line 141

def self.ad_impl(args, env, f)
  l = args.car.evaluate(env)
  raise "list required." unless l.list?
  l.send(f)
end

.any_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 448

def self.any_impl(args, env)
  raise "any requires at least two arguments" unless args.length >= 2
  p = args.car.evaluate(env)
  raise "any requires a function as it's first argument" unless p.function? || p.primitive?
  lists = args.cdr.to_a.collect {|a| a.evaluate(env)}
  raise "any requires all subsequent arguments to be lists or vectors" unless lists.all? {|l| l.list? || l.vector?}

  while true
    cars = lists.collect {|l| l.nth(1)}
    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(2)}
    return Lisp::FALSE if lists.any? {|l| l.empty?}
  end
end

.append_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 490

def self.append_impl(args, env)
  raise "append requires at least 1 argument." unless args.length >= 1
  l = args.map {|i| i.evaluate(env)}
  raise "append requires lists or vectors" unless l.all? {|i| i.list? || i.vector?}
  all_vectors = l.all? {|i| i.vector?}
  new_items = []
  l.each do |sublist|
    sublist.each {|item| new_items << item.copy}
  end

  if all_vectors
    Lisp::Vector.new(new_items)
  else
    Lisp::ConsCell.array_to_list(new_items)
  end
end

.appendbang_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 508

def self.appendbang_impl(args, env)
  raise "append! requires at least 1 argument." unless args.length >= 1
  arg_array = args.to_a.map {|i| i.evaluate(env)}
  raise "append! requires lists" 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 



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# File 'lib/rubylisp/list_support.rb', line 61

def self.cons_impl(args, env)
  raise "cons requires two arguments." unless args.length == 2
  left = args.car.evaluate(env)
  right = args.cadr.evaluate(env)
  Lisp::ConsCell.cons(left, right)
end

.cons_star_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 69

def self.cons_star_impl(args, env)
  vals = []
  args.each {|item| vals << item.evaluate(env) }
  Lisp::ConsCell::array_to_list(vals[0..-2], vals[-1])
end

.drop_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 307

def self.drop_impl(args, env)
  raise "drop requires 2 arguments" unless args.length == 2
  k = args.car.evaluate(env)
  raise "drop requires it's first argument to be an integer >= 0, but received #{args.car}" unless k.number? && !k.negative?
  l = args.cadr.evaluate(env)
  raise "drop requires it's second argument to be a list or vector, but received #{args.cadr}" unless l.list? || l.vector?
  raise "drop requires it's first argument to be <= the list length" unless k.value <= l.length
  l.nth_tail(k.value + 1)
end

.eighth_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 214

def self.eighth_impl(args, env)
  l = args.car.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  raise "list index out of bounds" unless l.length >= 8
  l.nth(8)
end

.every_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 465

def self.every_impl(args, env)
  raise "all requires at least two arguments" unless args.length >= 2
  p = args.car.evaluate(env)
  raise "all requires a function as it's first argument" unless p.function? || p.primitive?
  lists = args.cdr.to_a.collect {|a| a.evaluate(env)}
  raise "all requires all subsequent arguments to be lists or vectors" unless lists.all? {|l| l.list? || l.vector?}

  while true
    cars = lists.collect {|l| l.nth(1)}
    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(2)}
    return Lisp::TRUE if lists.any? {|l| l.empty?}
  end
end

.fifth_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 190

def self.fifth_impl(args, env)
  l = args.car.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  raise "list index out of bounds" unless l.length >= 5
  l.nth(5)
end

.filter_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 368

def self.filter_impl(args, env)
  raise "filter requires 2 arguments but received #{args.length}." unless args.length == 2
  f = args.car.evaluate(env)
  raise "filter requires a function as it's first argument but received #{args.car}." unless f.function? || f.primitive?
  collection = args.cadr.evaluate(env)
  raise "filter requires a list or vector as it's second argument but received #{args.cadr}." unless collection.list? || collection.vector?
  results = collection.to_a.select {|item| f.apply_to_without_evaluating(Lisp::ConsCell.cons(item, nil), env).value }
  make_same_kind_as(collection, results)
end

.first_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 148

def self.first_impl(args, env)
  l = args.car.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  raise "list index out of bounds" unless l.length >= 1
  l.nth(1)
end

.flatten_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 519

def self.flatten_impl(args, env)
  raise "flatten requires 1 argument." unless args.length != 1
  l = args.car.evaluate(env)
  raise "flatten requires a list argument" unless l.list?
  l.flatten
end

.fourth_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 182

def self.fourth_impl(args, env)
  l = args.car.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  raise "list index out of bounds" unless l.length >= 4
  l.nth(4)
end

.iota_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 103

def self.iota_impl(args, env)
  raise "iota requires at least one argument." unless args.length > 0
  arg1 = args.car.evaluate(env)
  raise "iota requires an positive integer for it's first argument, received: #{args.car}" unless arg1.integer? && arg1.positive?
  count = arg1.value

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

  step = if args.length < 3
            1
          else
            arg3 = args.caddr.evaluate(env)
            raise "iota requires an number for it's third argument, received: #{args.caddr}" 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 



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# File 'lib/rubylisp/list_support.rb', line 318

def self.last_pair_impl(args, env)
  raise "last_pair requires 1 arguments" unless args.length == 1
  l = args.car.evaluate(env)
  raise "last_pair requires it's argument to be a list, but received #{args.car}" unless l.list?
  l.last
end

.length_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 135

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

.list_head_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 273

def self.list_head_impl(args, env)
  raise "list_head requires 2 arguments" unless args.length == 2
  l = args.car.evaluate(env)
  raise "list_head requires it's first argument to be a list, but received #{args.car}" unless l.list?
  k = args.cadr.evaluate(env)
  raise "list_head requires it's second argument to be a positive integer, but received #{args.cadr}" unless k.number? && k.positive?
  raise "list_head requires it's second argument to be <= the list length" unless k.value <= l.length
  Lisp::ConsCell.array_to_list(l.to_a[0...k.value])
end

.list_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 76

def self.list_impl(args, env)
  vals = []
  args.each {|item| vals << item.evaluate(env) }
  if vals.size == 1 && vals[0].vector?
    Lisp::ConsCell::array_to_list(vals[0].value)
  else
    Lisp::ConsCell::array_to_list(vals)
  end
end

.list_tail_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 296

def self.list_tail_impl(args, env)
  raise "list_head requires 2 arguments" unless args.length == 2
  l = args.car.evaluate(env)
  raise "list_head requires it's first argument to be a list, but received #{args.car}" unless l.list?
  k = args.cadr.evaluate(env)
  raise "list_head requires it's second argument to be a positive integer, but received #{args.cadr}" unless k.number? && k.positive?
  raise "list_head requires it's second argument to be <= the list length" unless k.value <= l.length
  l.nth_tail(k.value + 1)
end

.make_list_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 87

def self.make_list_impl(args, env)
  raise "consmake-list requires one or two arguments." unless args.length == 1 || args.length == 2
  arg1 = args.car.evaluate(env)
  raise "make-list requires an integer for it's first argument, received: #{args.car}" unless arg1.integer?
  count = arg1.value
  val = if args.length == 1
          nil
        else
          args.cadr.evaluate(env)
        end

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

.make_same_kind_as(sequence, value) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 249

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 



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# File 'lib/rubylisp/list_support.rb', line 403

def self.map_impl(args, env)
  raise "map requires at least 2 arguments but received #{args.length}." if args.length < 2
  f = args.car.evaluate(env)
  raise "map requires a function as it's first argument but received #{args.car}." unless f.function? || f.primitive?
  collections = args.cdr.to_a.collect {|a| a.evaluate(env)}
  raise "all requires all subsequent arguments to be lists or vectors" unless collections.all? {|l| l.list? || l.vector?}
  all_vectors = collections.all? {|i| i.vector?}
  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) }
  if all_vectors
    Lisp::Vector.new(results)
  else
    Lisp::ConsCell.array_to_list(results)
  end

end

.member_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 354

def self.member_impl(args, env)
  raise "member requires 2 arguments but received #{args.length}." unless args.length == 2
  item = args.car.evaluate(env)
  collection = args.cadr.evaluate(env)
  raise "member requires a list as it's second argument." unless collection.list?
  collection.length.times do |i|
    if Lisp::Equivalence.equal_check(item, collection.nth(i + 1)).value
      return collection.nth_tail(i + 1)
    end
  end
  Lisp::FALSE
end

.memq_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 326

def self.memq_impl(args, env)
  raise "memq requires 2 arguments but received #{args.length}." unless args.length == 2
  item = args.car.evaluate(env)
  collection = args.cadr.evaluate(env)
  raise "memq requires a list as it's second argument." unless collection.list?
  collection.length.times do |i|
    if Lisp::Equivalence.eq_check(item, collection.nth(i + 1)).value
      return collection.nth_tail(i + 1)
    end
  end
  Lisp::FALSE
end

.memv_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 340

def self.memv_impl(args, env)
  raise "memv requires 2 arguments but received #{args.length}." unless args.length == 2
  item = args.car.evaluate(env)
  collection = args.cadr.evaluate(env)
  raise "memv requires a list as it's second argument." unless collection.list?
  collection.length.times do |i|
    if Lisp::Equivalence.eqv_check(item, collection.nth(i + 1)).value
      return collection.nth_tail(i + 1)
    end
  end
  Lisp::FALSE
end

.ninth_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 222

def self.ninth_impl(args, env)
  l = args.car.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  raise "list index out of bounds" unless l.length >= 9
  l.nth(9)
end

.nth_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 238

def self.nth_impl(args, env)
  raise "nth requires 2 arguments" unless args.length == 2
  n = args.car.evaluate(env)
  raise "The first argument of nth has to be an number." unless n.number?
  raise "The first argument of nth has to be positive." unless n.value > 0
  l = args.cadr.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  l.nth(n.value)
end

.partition_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 390

def self.partition_impl(args, env)
  raise "partition requires 2 arguments but received #{args.length}." unless args.length == 2
  f = args.car.evaluate(env)
  raise "partition requires a function as it's first argument." unless f.function? || f.primitive?
  collection = args.cadr.evaluate(env)
  raise "partition requires a list as it's second argument." unless collection.list? | collection.vector?
  results = collection.to_a.partition {|item| f.apply_to_without_evaluating(Lisp::ConsCell.cons(item, nil), env).value }
  matches = make_same_kind_as(collection, results[0])
  non_matches = make_same_kind_as(collection, results[1])
  Lisp::ConsCell.array_to_list([matches, non_matches])
end

.quote_if_required(thing) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 426

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

.reduce_left_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 432

def self.reduce_left_impl(args, env)
  raise "reduce requires 3 arguments but received #{args.length}." unless args.length == 3
  f = args.car.evaluate(env)
  raise "map requires a function as it's first argument but received #{args.car}." unless f.function? || f.primitive?
  initial = args.cadr.evaluate(env)
  collection = args.caddr.evaluate(env)
  raise "reduce requires a list or vector as it's third argument but received #{args.caddr}." unless collection.list? || collection.vector?
  return initial if collection.empty?
  return collection.nth(1) if collection.length == 1
  result = collection.to_a.inject do |acc, item|
    f.apply_to(Lisp::ConsCell.array_to_list([quote_if_required(acc), quote_if_required(item)]), env)
  end
  result
end

.register ⇒ Object 



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# File 'lib/rubylisp/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) {|args, env| ad_impl(args, env, name) }
  end
  Primitive.register("list") {|args, env|  Lisp::ListSupport::list_impl(args, env) }
  Primitive.register("vector") {|args, env|  Lisp::ListSupport::vector_impl(args, env) }
  Primitive.register("cons*") {|args, env|  Lisp::ListSupport::cons_star_impl(args, env) }
  Primitive.register("cons") {|args, env|  Lisp::ListSupport::cons_impl(args, env) }
  Primitive.register("make-list") {|args, env|  Lisp::ListSupport::make_list_impl(args, env) }
  Primitive.register("iota") {|args, env|  Lisp::ListSupport::iota_impl(args, env) }

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

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

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

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

.remove_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 379

def self.remove_impl(args, env)
  raise "remove requires 2 arguments but received #{args.length}." unless args.length == 2
  f = args.car.evaluate(env)
  raise "remove requires a function as it's first argument but received #{args.car}." unless f.function? || f.primitive?
  collection = args.cadr.evaluate(env)
  raise "remove requires a list or vector as it's second argument but received #{args.cadr}." unless collection.list? || collection.vector?
  results = collection.to_a.reject {|item| f.apply_to_without_evaluating(Lisp::ConsCell.cons(item, nil), env).value }
  make_same_kind_as(collection, results)
end

.rest_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 156

def self.rest_impl(args, env)
  l = args.car.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  if l.list?
    l.cdr
  else
    Lisp::Vector.new(l.value[1..-1])
  end
end

.reverse_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 482

def self.reverse_impl(args, env)
  raise "reverse requires a single argument." unless args.length == 1
  l = args.car.evaluate(env)
  raise "reverse requires a list or vector" unless l.list? || l.vector?
  make_same_kind_as(l, l.to_a.reverse)
end

.second_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 167

def self.second_impl(args, env)
  l = args.car.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  raise "list index out of bounds" unless l.length >= 2
  l.nth(2)
end

.seventh_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 206

def self.seventh_impl(args, env)
  l = args.car.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  raise "list index out of bounds" unless l.length >= 7
  l.nth(7)
end

.sixth_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 198

def self.sixth_impl(args, env)
  l = args.car.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  raise "list index out of bounds" unless l.length >= 6
  l.nth(6)
end

.sublist_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 258

def self.sublist_impl(args, env)
  raise "sublist requires 3 arguments" unless args.length == 3
  l = args.car.evaluate(env)
  raise "sublist requires it's first argument to be a list or vector, but received #{args.car}" unless l.list? || l.vector?
  st = args.cadr.evaluate(env)
  raise "sublist requires it's second argument to be a positive integer, but received #{args.cadr}" unless st.number? && st.positive?
  raise "sublist requires it's second argument to be <= the list length" unless st.value <= l.length
  en = args.caddr.evaluate(env)
  raise "sublist requires it's third argument to be a positive integer, but received #{args.caddr}" unless en.number? && en.positive?
  raise "sublist requires it's third argument to be <= the list length" unless en.value <= l.length
  raise "sublist requires it's second argument to be <= the third argument" unless st.value <= en.value
  make_same_kind_as(l, l.to_a[(st.value - 1)...en.value])
end

.take_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 284

def self.take_impl(args, env)
  raise "take requires 2 arguments" unless args.length == 2
  k = args.car.evaluate(env)
  raise "take requires it's first argument to be an integer >= 0, but received #{args.car}" unless k.number? && !k.negative?
  l = args.cadr.evaluate(env)
  raise "take requires it's second argument to be a list or vector, but received #{args.cadr}" unless l.list? || l.vector?
  raise "take requires it's first argument to be <= the list length" unless k.value <= l.length
  puts l
  make_same_kind_as(l, l.to_a[0...k.value])
end

.tenth_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 230

def self.tenth_impl(args, env)
  l = args.car.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  raise "list index out of bounds" unless l.length >= 10
  l.nth(10)
end

.third_impl(args, env) ⇒ Object 



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# File 'lib/rubylisp/list_support.rb', line 174

def self.third_impl(args, env)
  l = args.car.evaluate(env)
  raise "rest requires a list or vector." unless l.list? || l.vector?
  raise "list index out of bounds" unless l.length >= 3
  l.nth(3)
end