method

enum_for

v2_2_9 - Show latest stable - 0 notes - Class: Lazy

1_8_6_287
1_8_7_72
1_8_7_330
1_9_1_378
1_9_2_180
1_9_3_125
1_9_3_392
2_1_10 (0)
2_2_9 (0)
2_4_6 (0)
2_5_5 (0)
2_6_3 (0)
What's this?

enum_for(*args) public

Similar to Kernel#to_enum, except it returns a lazy enumerator. This makes it easy to define Enumerable methods that will naturally remain lazy if called from a lazy enumerator.

For example, continuing from the example in Kernel#to_enum:

# See Kernel#to_enum for the definition of repeat
r = 1..Float::INFINITY
r.repeat(2).first(5) # => [1, 1, 2, 2, 3]
r.repeat(2).class # => Enumerator
r.repeat(2).map{|n| n ** 2}.first(5) # => endless loop!
# works naturally on lazy enumerator:
r.lazy.repeat(2).class # => Enumerator::Lazy
r.lazy.repeat(2).map{|n| n ** 2}.first(5) # => [1, 1, 4, 4, 9]

Show source

static VALUE
lazy_to_enum(int argc, VALUE *argv, VALUE self)
{
    VALUE lazy, meth = sym_each;

    if (argc > 0) {
        --argc;
        meth = *argv++;
    }
    lazy = lazy_to_enum_i(self, meth, argc, argv, 0);
    if (rb_block_given_p()) {
        enumerator_ptr(lazy)->size = rb_block_proc();
    }
    return lazy;
}

enum_for

Related methods