From 9760a7f905367e96d6c22bbace1680d694fa16bd Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Thu, 19 Apr 2018 05:55:42 +0000
Subject: Add slice method to ENV like Hash#slice

[Feature #14559]

From:    Benoit Tigeot <benoit@hopsandfork.com>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63188 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 hash.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

(limited to 'hash.c')

diff --git a/hash.c b/hash.c
index 3a499872ad..c8125a0d6c 100644
--- a/hash.c
+++ b/hash.c
@@ -4067,6 +4067,35 @@ env_keep_if(VALUE ehash)
     return envtbl;
 }
 
+/*
+ *  call-seq:
+ *     ENV.slice(*keys) -> a_hash
+ *
+ *  Returns a hash containing only the given keys from ENV and their values.
+ *
+ *     ENV.slice("TERM","HOME")  #=> {"TERM"=>"xterm-256color", "HOME"=>"/Users/rhc"}
+ */
+static VALUE
+env_slice(int argc, VALUE *argv)
+{
+    int i;
+    VALUE key, value, result;
+
+    if (argc == 0) {
+        return rb_hash_new();
+    }
+    result = rb_hash_new_with_size(argc);
+
+    for (i = 0; i < argc; i++) {
+        key = argv[i];
+        value = rb_f_getenv(Qnil, key);
+        if (value != Qnil)
+            rb_hash_aset(result, key, value);
+    }
+
+    return result;
+}
+
 /*
  * call-seq:
  *   ENV.clear
@@ -4749,6 +4778,7 @@ Init_Hash(void)
     rb_define_singleton_method(envtbl, "delete", env_delete_m, 1);
     rb_define_singleton_method(envtbl, "delete_if", env_delete_if, 0);
     rb_define_singleton_method(envtbl, "keep_if", env_keep_if, 0);
+    rb_define_singleton_method(envtbl, "slice", env_slice, -1);
     rb_define_singleton_method(envtbl, "clear", rb_env_clear, 0);
     rb_define_singleton_method(envtbl, "reject", env_reject, 0);
     rb_define_singleton_method(envtbl, "reject!", env_reject_bang, 0);
-- 
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