From: nobu@...
Date: 2015-12-09T07:51:18+00:00
Subject: [ruby-core:71989] [Ruby trunk - Feature #11781] Would it be possible to alias .prepend() towards .unshift() for class Array by default?

Issue #11781 has been updated by Nobuyoshi Nakada.


Their arities differ.
Let `String#prepend` take any number of arguments?

~~~diff
diff --git i/array.c w/array.c
index dd14837..b98142d 100644
--- i/array.c
+++ w/array.c
@@ -5832,6 +5832,7 @@ Init_Array(void)
     rb_define_method(rb_cArray, "pop", rb_ary_pop_m, -1);
     rb_define_method(rb_cArray, "shift", rb_ary_shift_m, -1);
     rb_define_method(rb_cArray, "unshift", rb_ary_unshift_m, -1);
+    rb_define_method(rb_cArray, "prepend", rb_ary_unshift_m, -1);
     rb_define_method(rb_cArray, "insert", rb_ary_insert, -1);
     rb_define_method(rb_cArray, "each", rb_ary_each, 0);
     rb_define_method(rb_cArray, "each_index", rb_ary_each_index, 0);
diff --git i/string.c w/string.c
index e6df91d..d0f6454 100644
--- i/string.c
+++ w/string.c
@@ -2691,21 +2691,28 @@ rb_str_concat(VALUE str1, VALUE str2)
 
 /*
  *  call-seq:
- *     str.prepend(other_str)  -> str
+ *     str.prepend(other_str, ...)  -> str
  *
  *  Prepend---Prepend the given string to <i>str</i>.
  *
  *     a = "world"
  *     a.prepend("hello ") #=> "hello world"
  *     a                   #=> "hello world"
+ *
+ *     a = "world"
+ *     a.prepend("hello", " ") #=> "hello world"
+ *     a                       #=> "hello world"
  */
 
 static VALUE
-rb_str_prepend(VALUE str, VALUE str2)
+rb_str_prepend(int argc, VALUE *argv, VALUE str)
 {
-    StringValue(str2);
-    StringValue(str);
-    rb_str_update(str, 0L, 0L, str2);
+    int i;
+    for (i = argc; i > 0;) {
+	VALUE str2 = argv[--i];
+	StringValue(str2);
+	rb_str_update(str, 0L, 0L, str2);
+    }
     return str;
 }
 
@@ -9379,7 +9386,8 @@ Init_String(void)
     rb_define_method(rb_cString, "reverse!", rb_str_reverse_bang, 0);
     rb_define_method(rb_cString, "concat", rb_str_concat, 1);
     rb_define_method(rb_cString, "<<", rb_str_concat, 1);
-    rb_define_method(rb_cString, "prepend", rb_str_prepend, 1);
+    rb_define_method(rb_cString, "prepend", rb_str_prepend, -1);
+    rb_define_method(rb_cString, "unshift", rb_str_prepend, -1);
     rb_define_method(rb_cString, "crypt", rb_str_crypt, 1);
     rb_define_method(rb_cString, "intern", rb_str_intern, 0); /* in symbol.c */
     rb_define_method(rb_cString, "to_sym", rb_str_intern, 0); /* in symbol.c */
diff --git i/test/ruby/test_string.rb w/test/ruby/test_string.rb
index eed7c69..853ef7c 100644
--- i/test/ruby/test_string.rb
+++ w/test/ruby/test_string.rb
@@ -2194,6 +2194,14 @@
     a.prepend(b)
     assert_equal(S("hello world"), a)
     assert_equal(S("hello "), b)
+
+    a = S("world")
+    b = S("hel")
+    c = S("lo ")
+    a.prepend(b, c)
+    assert_equal(S("hello world"), a)
+    assert_equal(S("hel"), b)
+    assert_equal(S("lo "), c)
   end
 
   def u(str)


----------------------------------------
Feature #11781: Would it be possible to alias .prepend() towards .unshift() for class Array by default?
https://bugs.ruby-lang.org/issues/11781#change-55399

* Author: Robert A. Heiler
* Status: Open
* Priority: Normal
* Assignee: 
----------------------------------------
Hello.

For Strings we can do:

    abc = 'world!'
    abc[0,0] = 'Hello '
    abc # => "Hello world!"

For Arrays we can do:

    abc = ['world!']
    abc[0,0] = 'Hello '
    abc # => ["Hello ", "world!"]

This is nice.

For Strings we can also use .prepend() to add to the beginning.

For Arrays, we have to use .unshift().

I have a hard time remembering .unshift though, .prepend() seems
to be easier for me to remember.

I'd like to use both .prepend for Strings and Arrays; right now
I have to use different names. I could alias prepend to unshift
for class Array, but then I'd have to carry these modifications
into my projects, which is not so good - I would prefer to just
stick to what MRI is doing.

Could we have the alias .prepend() for class Array, meaning 
.unshift() too? That way I could use .prepend() for both Arrays
and Strings.

Thanks for reading!



-- 
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