/*
* call-seq:
* Enumerator.new(size = nil) { |yielder| ... }
* Enumerator.new(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]
*
* The optional parameter can be used to specify how to calculate the size
* in a lazy fashion (see Enumerator#size). It can either be a value or
* a callable object.
*
* In the second, deprecated, form, a generated Enumerator iterates over the
* given object using the given method with the given arguments passed.
*
* Use of this form is discouraged. Use Kernel#enum_for or Kernel#to_enum
* instead.
*
* e = Enumerator.new(ObjectSpace, :each_object)
* #-> ObjectSpace.enum_for(:each_object)
*
* e.select { |obj| obj.is_a?(Class) } #=> array of all classes
*
*/
static VALUE
enumerator_initialize(int argc, VALUE *argv, VALUE obj)
{
VALUE recv, meth = sym_each;
VALUE size = Qnil;
if (rb_block_given_p()) {
rb_check_arity(argc, 0, 1);
recv = generator_init(generator_allocate(rb_cGenerator), rb_block_proc());
if (argc) {
if (NIL_P(argv[0]) || rb_obj_is_proc(argv[0]) ||
(RB_TYPE_P(argv[0], T_FLOAT) && RFLOAT_VALUE(argv[0]) == INFINITY)) {
size = argv[0];
}
else {
size = rb_to_int(argv[0]);
}
argc = 0;
}
}
else {
rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
rb_warn("Enumerator.new without a block is deprecated; use Object#to_enum");
recv = *argv++;
if (--argc) {
meth = *argv++;
--argc;
}
}
return enumerator_init(obj, recv, meth, argc, argv, 0, size);
}
static VALUE
lazy_initialize(int argc, VALUE *argv, VALUE self)
{
VALUE obj, meth;
VALUE generator;
int offset;
if (argc < 1) {
rb_raise(rb_eArgError, "wrong number of arguments (%d for 1..)", argc);
}
else {
obj = argv[0];
if (argc == 1) {
meth = sym_each;
offset = 1;
}
else {
meth = argv[1];
offset = 2;
}
}
generator = generator_allocate(rb_cGenerator);
rb_block_call(generator, id_initialize, 0, 0,
(rb_block_given_p() ? lazy_init_block_i : lazy_init_block),
obj);
enumerator_init(self, generator, meth, argc - offset, argv + offset);
rb_ivar_set(self, id_receiver, obj);
return self;
}
/*
* call-seq:
* Enumerator.new(obj, method = :each, *args)
* Enumerator.new { |y| ... }
*
* Creates a new Enumerator object, which is to be used as an
* Enumerable object iterating in a given way.
*
* In the first form, a generated Enumerator iterates over the given
* object using the given method with the given arguments passed.
* Use of this form is discouraged. Use Kernel#enum_for(), alias
* to_enum, instead.
*
* e = Enumerator.new(ObjectSpace, :each_object)
* #-> ObjectSpace.enum_for(:each_object)
*
* e.select { |obj| obj.is_a?(Class) } #=> array of all classes
*
* In the second 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, alias +<<+.
*
* fib = Enumerator.new { |y|
* a = b = 1
* loop {
* y << a
* a, b = b, a + b
* }
* }
*
* p fib.take(10) #=> [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
*/
static VALUE
enumerator_initialize(int argc, VALUE *argv, VALUE obj)
{
VALUE recv, meth = sym_each;
if (argc == 0) {
if (!rb_block_given_p())
rb_raise(rb_eArgError, "wrong number of argument (0 for 1+)");
recv = generator_init(generator_allocate(rb_cGenerator), rb_block_proc());
} else {
recv = *argv++;
if (--argc) {
meth = *argv++;
--argc;
}
}
return enumerator_init(obj, recv, meth, argc, argv);
}
/*
* call-seq:
* Lazy.new(obj, size=nil) { |yielder, *values| ... }
*
* Creates a new Lazy enumerator. When the enumerator is actually enumerated
* (e.g. by calling #force), +obj+ will be enumerated and each value passed
* to the given block. The block can yield values back using +yielder+.
* For example, to create a method +filter_map+ in both lazy and
* non-lazy fashions:
*
* module Enumerable
* def filter_map(&block)
* map(&block).compact
* end
* end
*
* class Enumerator::Lazy
* def filter_map
* Lazy.new(self) do |yielder, *values|
* result = yield *values
* yielder << result if result
* end
* end
* end
*
* (1..Float::INFINITY).lazy.filter_map{|i| i*i if i.even?}.first(5)
* # => [4, 16, 36, 64, 100]
*/
static VALUE
lazy_initialize(int argc, VALUE *argv, VALUE self)
{
VALUE obj, size = Qnil;
VALUE generator;
rb_check_arity(argc, 1, 2);
if (!rb_block_given_p()) {
rb_raise(rb_eArgError, "tried to call lazy new without a block");
}
obj = argv[0];
if (argc > 1) {
size = argv[1];
}
generator = generator_allocate(rb_cGenerator);
rb_block_call(generator, id_initialize, 0, 0, lazy_init_block_i, obj);
enumerator_init(self, generator, sym_each, 0, 0, 0, size);
rb_ivar_set(self, id_receiver, obj);
return self;
}
/*
* call-seq:
* Enumerator.new { |yielder| ... }
* Enumerator.new(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]
*
* The block form can be used to create a lazy enumeration that only processes
* elements as-needed. The generic pattern for this is:
*
* Enumerator.new do |yielder|
* source.each do |source_item|
* # process source_item and append the yielder
* end
* end
*
* This can be used with infinite streams to support multiple chains:
*
* class Fib
* def initialize(a = 1, b = 1)
* @a, @b = a, b
* end
*
* def each
* a, b = @a, @b
* yield a
* while true
* yield b
* a, b = b, a+b
* end
* end
* end
*
* def lazy_select enum
* Enumerator.new do |y|
* enum.each do |e|
* y << e if yield e
* end
* end
* end
*
* def lazy_map enum
* Enumerator.new do |y|
* enum.each do |e|
* y << yield(e)
* end
* end
* end
*
* even_fibs = lazy_select(Fibs.new) { |x| x % 2 == 0 }
* string_fibs = lazy_map(even_fibs) { |x| "<#{x}>" }
* string_fibs.each_with_index do |fib, i|
* puts "#{i}: #{fib}"
* break if i >= 3
* end
*
* This allows output even though the Fib produces an infinite sequence of
* Fibonacci numbers:
*
* 0: <2>
* 1: <8>
* 2: <34>
* 3: <144>
*
* In the second, deprecated, form, a generated Enumerator iterates over the
* given object using the given method with the given arguments passed.
*
* Use of this form is discouraged. Use Kernel#enum_for or Kernel#to_enum
* instead.
*
* e = Enumerator.new(ObjectSpace, :each_object)
* #-> ObjectSpace.enum_for(:each_object)
*
* e.select { |obj| obj.is_a?(Class) } #=> array of all classes
*
*/
static VALUE
enumerator_initialize(int argc, VALUE *argv, VALUE obj)
{
VALUE recv, meth = sym_each;
if (argc == 0) {
if (!rb_block_given_p())
rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
recv = generator_init(generator_allocate(rb_cGenerator), rb_block_proc());
}
else {
recv = *argv++;
if (--argc) {
meth = *argv++;
--argc;
}
}
return enumerator_init(obj, recv, meth, argc, argv);
}
/*
* call-seq:
* Enumerator.new(obj, method = :each, *args)
* Enumerator.new { |y| ... }
*
* Creates a new Enumerator object, which is to be used as an
* Enumerable object iterating in a given way.
*
* In the first form, a generated Enumerator iterates over the given
* object using the given method with the given arguments passed.
* Use of this form is discouraged. Use Kernel#enum_for(), alias
* to_enum, instead.
*
* e = Enumerator.new(ObjectSpace, :each_object)
* #-> ObjectSpace.enum_for(:each_object)
*
* e.select { |obj| obj.is_a?(Class) } #=> array of all classes
*
* In the second 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, alias +<<+.
*
* fib = Enumerator.new { |y|
* a = b = 1
* loop {
* y << a
* a, b = b, a + b
* }
* }
*
* p fib.take(10) #=> [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
*/
static VALUE
enumerator_initialize(VALUE obj, SEL sel, int argc, VALUE *argv)
{
VALUE recv, meth = sym_each;
if (argc == 0) {
if (!rb_block_given_p())
rb_raise(rb_eArgError, "wrong number of argument (0 for 1+)");
recv = generator_init(generator_allocate(rb_cGenerator, 0), rb_block_proc());
}
else {
recv = *argv++;
if (--argc) {
meth = *argv++;
--argc;
}
}
ID meth_id = rb_to_id(meth);
SEL meth_sel = rb_vm_id_to_sel(meth_id, argc);
return enumerator_init(obj, recv, meth_sel, argc, argv);
}