Adding Enumerable#filter_map

[Feature #15323]
Closes: https://github.com/ruby/ruby/pull/2017

1 files changed, 41 insertions, 0 deletions

diff --git a/enum.c b/enum.c
index d754005ab2..d7def94ebf 100644
--- a/enum.c
+++ b/enum.c
@@ -453,6 +453,46 @@ enum_find_all(VALUE obj)
 }
 
 static VALUE
+filter_map_i(RB_BLOCK_CALL_FUNC_ARGLIST(i, ary))
+{
+    i = rb_yield_values2(argc, argv);
+
+    if (RTEST(i)) {
+        rb_ary_push(ary, i);
+    }
+
+    return Qnil;
+}
+
+/*
+ *  call-seq:
+ *     enum.filter_map { |obj| block } -> array
+ *     enum.filter_map                 -> an_enumerator
+ *
+ *  Returns a new array containing the truthy results (everything except
+ *  +false+ or +nil+) of running the +block+ for every element in +enum+.
+ *
+ *  If no block is given, an Enumerator is returned instead.
+ *
+ *
+ *     (1..10).filter_map { |i| i * 2 if i.even? } #=> [4, 8, 12, 16, 20]
+ *
+ */
+static VALUE
+enum_filter_map(VALUE obj)
+{
+    VALUE ary;
+
+    RETURN_SIZED_ENUMERATOR(obj, 0, 0, enum_size);
+
+    ary = rb_ary_new();
+    rb_block_call(obj, id_each, 0, 0, filter_map_i, ary);
+
+    return ary;
+}
+
+
+static VALUE
 reject_i(RB_BLOCK_CALL_FUNC_ARGLIST(i, ary))
 {
     ENUM_WANT_SVALUE();
@@ -4108,6 +4148,7 @@ Init_Enumerable(void)
     rb_define_method(rb_mEnumerable, "find_all", enum_find_all, 0);
     rb_define_method(rb_mEnumerable, "select", enum_find_all, 0);
     rb_define_method(rb_mEnumerable, "filter", enum_find_all, 0);
+    rb_define_method(rb_mEnumerable, "filter_map", enum_filter_map, 0);
     rb_define_method(rb_mEnumerable, "reject", enum_reject, 0);
     rb_define_method(rb_mEnumerable, "collect", enum_collect, 0);
     rb_define_method(rb_mEnumerable, "map", enum_collect, 0);