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| -rw-r--r-- | ChangeLog | 4 | ||||
| -rw-r--r-- | enumerator.c | 21 |
2 files changed, 25 insertions, 0 deletions
@@ -1,3 +1,7 @@ +Tue Mar 13 00:09:18 2012 Shugo Maeda <shugo@ruby-lang.org> + + * enumerator.c (enumerable_lazy): added documentation. + Mon Mar 12 20:19:25 2012 Tanaka Akira <akr@fsij.org> * lib/tmpdir.rb (Dir::tmpdir): test the current directory suitable for diff --git a/enumerator.c b/enumerator.c index 8e02021386..5e91673899 100644 --- a/enumerator.c +++ b/enumerator.c @@ -1247,6 +1247,27 @@ lazy_initialize(VALUE self, VALUE obj) /* * call-seq: * e.lazy -> lazy_enumerator + * + * Returns a lazy enumerator, whose methods map/collect, + * flat_map/collect_concat, select/find_all, reject, and grep call blocks + * only on an as-needed basis. + * + * === Example + * + * The following program shows all pythagorean triples less than 100: + * + * def pythagorean_triples + * (1..Float::INFINITY).lazy.flat_map {|z| + * (1..z).flat_map {|x| + * (x..z).select {|y| + * x**2 + y**2 == z**2 + * }.map {|y| + * [x, y, z] + * } + * } + * } + * end + * p pythagorean_triples.take_while { |x, y, z| z < 100 } */ static VALUE enumerable_lazy(VALUE obj) |