Add Enumerable#join

Author: nobu

array.c

@@ -2791,7 +2791,7 @@ rb_ary_resurrect(VALUE ary)
     return ary_make_partial(ary, rb_cArray, 0, RARRAY_LEN(ary));
 }
 
-extern VALUE rb_output_fs;
+extern VALUE rb_get_output_fs(void);
 
 static void ary_join_1(VALUE obj, VALUE ary, VALUE sep, long i, VALUE result, int *first);
 
@@ -2858,31 +2858,37 @@ ary_join_1_ary(VALUE obj, VALUE ary, VALUE sep, VALUE result, VALUE val, int *fi
     }
 }
 
+void
+rb_ary_join_1(VALUE obj, VALUE ary, VALUE val, VALUE sep, VALUE result, int *first)
+{
+    VALUE tmp;
+
+    if (!*first && !NIL_P(sep))
+        rb_str_buf_append(result, sep);
+
+    if (RB_TYPE_P(val, T_STRING)) {
+        ary_join_1_str(result, val, first);
+    }
+    else if (RB_TYPE_P(val, T_ARRAY)) {
+        ary_join_1_ary(val, ary, sep, result, val, first);
+    }
+    else if (!NIL_P(tmp = rb_check_string_type(val))) {
+        ary_join_1_str(result, tmp, first);
+    }
+    else if (!NIL_P(tmp = rb_check_array_type(val))) {
+        ary_join_1_ary(val, ary, sep, result, tmp, first);
+    }
+    else {
+        ary_join_1_str(result, rb_obj_as_string(val), first);
+    }
+}
+
 static void
 ary_join_1(VALUE obj, VALUE ary, VALUE sep, long i, VALUE result, int *first)
 {
-    VALUE val, tmp;
-
     for (; i<RARRAY_LEN(ary); i++) {
-        if (i > 0 && !NIL_P(sep))
-            rb_str_buf_append(result, sep);
-
-        val = RARRAY_AREF(ary, i);
-        if (RB_TYPE_P(val, T_STRING)) {
-            ary_join_1_str(result, val, first);
-        }
-        else if (RB_TYPE_P(val, T_ARRAY)) {
-            ary_join_1_ary(val, ary, sep, result, val, first);
-        }
-        else if (!NIL_P(tmp = rb_check_string_type(val))) {
-            ary_join_1_str(result, tmp, first);
-        }
-        else if (!NIL_P(tmp = rb_check_array_type(val))) {
-            ary_join_1_ary(val, ary, sep, result, tmp, first);
-        }
-        else {
-            ary_join_1_str(result, rb_obj_as_string(val), first);
-        }
+        VALUE val = RARRAY_AREF(ary, i);
+        rb_ary_join_1(obj, ary, val, sep, result, first);
     }
 }
 
@@ -2960,10 +2966,7 @@ rb_ary_join_m(int argc, VALUE *argv, VALUE ary)
     VALUE sep;
 
     if (rb_check_arity(argc, 0, 1) == 0 || NIL_P(sep = argv[0])) {
-        sep = rb_output_fs;
-        if (!NIL_P(sep)) {
-            rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$, is set to non-nil value");
-        }
+        sep = rb_get_output_fs();
     }
 
     return rb_ary_join(ary, sep);

enum.c

@@ -4948,6 +4948,75 @@ enum_compact(VALUE obj)
     return ary;
 }
 
+extern VALUE rb_get_output_fs(void);
+void rb_ary_join_1(VALUE obj, VALUE ary, VALUE val, VALUE sep, VALUE result, int *first);
+
+struct join_args {
+    VALUE obj;
+    VALUE sep;
+    VALUE result;
+    int first;
+};
+
+static VALUE
+join_i(RB_BLOCK_CALL_FUNC_ARGLIST(i, args))
+{
+    struct join_args *p = (void *)args;
+    ENUM_WANT_SVALUE();
+
+    rb_ary_join_1(p->obj, p->obj, i, p->sep, p->result, &p->first);
+    return p->result;
+}
+
+/*
+ *  call-seq:
+ *    join(separator = $,) -> new_string
+ *
+ *  Returns the new string formed by joining the converted elements of +self+;
+ *  Returns an array of all non-+nil+ elements:
+ *
+ *  - Converts recursively using <tt>element.join(separator)</tt>
+ *    if +element+ is a <tt>kind_of?(Array)</tt>.
+ *  - Otherwise, converts using <tt>element.to_s</tt>.
+ *
+ *  With no argument given, joins using the output field separator, <tt>$,</tt>:
+ *
+ *    a = [:foo, 'bar', 2].lazy
+ *    $, # => nil
+ *    a.join # => "foobar2"
+ *
+ *  With string argument +separator+ given, joins using that separator:
+ *
+ *    a = [:foo, 'bar', 2].lazy
+ *    a.join("\n") # => "foo\nbar\n2"
+ *
+ *  Joins recursively for nested arrays:
+ *
+ *   a = [:foo, [:bar, [:baz, :bat]]]
+ *   a.join # => "foobarbazbat"
+ *
+ *  See also Array#join.
+ */
+
+static VALUE
+enum_join(int argc, VALUE *argv, VALUE obj)
+{
+    struct join_args args = {
+        .result = Qnil,
+        .sep = Qnil,
+        .first = 1,
+    };
+
+    if (rb_check_arity(argc, 0, 1) == 0 || NIL_P(args.sep = argv[0])) {
+        args.sep = rb_get_output_fs();
+    }
+
+    args.result = rb_usascii_str_new(0, 0);
+    rb_block_call(obj, id_each, 0, 0, join_i, (VALUE)&args);
+
+    return args.result;
+}
+
 
 /*
  * == What's Here
@@ -5262,6 +5331,7 @@ Init_Enumerable(void)
     rb_define_method(rb_mEnumerable, "sum", enum_sum, -1);
     rb_define_method(rb_mEnumerable, "uniq", enum_uniq, 0);
     rb_define_method(rb_mEnumerable, "compact", enum_compact, 0);
+    rb_define_method(rb_mEnumerable, "join", enum_join, -1);
 
     id__alone = rb_intern_const("_alone");
     id__separator = rb_intern_const("_separator");

io.c

@@ -8699,6 +8699,16 @@ deprecated_rs_setter(VALUE val, ID id, VALUE *var)
     *var = val;
 }
 
+VALUE
+rb_get_output_fs(void)
+{
+    VALUE ofs = rb_output_fs;
+    if (!NIL_P(ofs)) {
+        rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$, is set to non-nil value");
+    }
+    return ofs;
+}
+
 /*
  *  call-seq:
  *    print(*objects) -> nil
@@ -8767,9 +8777,7 @@ rb_io_print(int argc, const VALUE *argv, VALUE out)
         line = rb_lastline_get();
         argv = &line;
     }
-    if (argc > 1 && !NIL_P(rb_output_fs)) {
-        rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$, is set to non-nil value");
-    }
+    if (argc > 1) rb_get_output_fs();
     for (i=0; i<argc; i++) {
         if (!NIL_P(rb_output_fs) && i>0) {
             rb_io_write(out, rb_output_fs);

test/ruby/test_enum.rb

@@ -1356,4 +1356,8 @@ def test_all_fast
     assert_equal(kk, "key")
     assert_equal(vv, { "key2" => 1 })
   end
+
+  def test_join
+    assert_equal "foobar2", [:foo, "bar", 2].each.join("")
+  end
 end

test/ruby/test_lazy_enumerator.rb

@@ -715,4 +715,8 @@ def test_with_index
   def test_with_index_size
     assert_equal(3, Enumerator::Lazy.new([1, 2, 3], 3){|y, v| y << v}.with_index.size)
   end
+
+  def test_join
+    assert_equal "ABC", (65..).lazy.map {|i| i.chr}.take(3).join("")
+  end
 end