From 006a8ba77f6c5e27201760dfe560eb0c63e4d70b Mon Sep 17 00:00:00 2001
From: matz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 3 Mar 2010 05:35:08 +0000
Subject: * array.c (rb_ary_select_bang): select! removes all elements for  
 which block returns false.  [ruby-core:27286]

* array.c (rb_ary_keep_if): #keep_if, new method.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@26800 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 array.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

(limited to 'array.c')

diff --git a/array.c b/array.c
index 02e6d1861d..a4c7565290 100644
--- a/array.c
+++ b/array.c
@@ -2248,6 +2248,57 @@ rb_ary_select(VALUE ary)
     return result;
 }
 
+/*
+ *  call-seq:
+ *     array.select! {|item| block } -> an_array
+ *
+ *  Invokes the block passing in successive elements from
+ *  <i>array</i>, deleting elements for which the block returns a
+ *  false value.  but returns <code>nil</code> if no changes were
+ *  made.  Also see <code>Array#keep_if</code>
+ */
+
+static VALUE
+rb_ary_select_bang(VALUE ary)
+{
+    long i1, i2;
+
+    RETURN_ENUMERATOR(ary, 0, 0);
+    rb_ary_modify(ary);
+    for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); i1++) {
+	VALUE v = RARRAY_PTR(ary)[i1];
+	if (!RTEST(rb_yield(v))) continue;
+	if (i1 != i2) {
+	    rb_ary_store(ary, i2, v);
+	}
+	i2++;
+    }
+
+    if (RARRAY_LEN(ary) == i2) return Qnil;
+    if (i2 < RARRAY_LEN(ary))
+	ARY_SET_LEN(ary, i2);
+    return ary;
+}
+
+/*
+ *  call-seq:
+ *     array.keep_if {|item| block } -> an_array
+ *
+ *  Deletes every element of <i>self</i> for which <i>block</i> evaluates
+ *  to <code>false</code>.
+ *
+ *     a = %w{ a b c d e f }
+ *     a.keep_if {|v| v =~ /[aeiou]/}   #=> ["a", "e"]
+ */
+
+static VALUE
+rb_ary_keep_if(VALUE ary)
+{
+    RETURN_ENUMERATOR(ary, 0, 0);
+    rb_ary_select_bang(ary);
+    return ary;
+}
+
 /*
  *  call-seq:
  *     array.delete(obj)            -> obj or nil
@@ -4239,6 +4290,8 @@ Init_Array(void)
     rb_define_method(rb_cArray, "map", rb_ary_collect, 0);
     rb_define_method(rb_cArray, "map!", rb_ary_collect_bang, 0);
     rb_define_method(rb_cArray, "select", rb_ary_select, 0);
+    rb_define_method(rb_cArray, "select!", rb_ary_select_bang, 0);
+    rb_define_method(rb_cArray, "keep_if", rb_ary_keep_if, 0);
     rb_define_method(rb_cArray, "values_at", rb_ary_values_at, -1);
     rb_define_method(rb_cArray, "delete", rb_ary_delete, 1);
     rb_define_method(rb_cArray, "delete_at", rb_ary_delete_at_m, 1);
-- 
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