Feature #12333
closed`String#concat`, `Array#concat`, `String#prepend` to take multiple arguments
Description
I would like String#concat
, Array#concat
, String#prepend
to take multiple arguments
s = ""
s.concat("a", "b", "c")
a.prepend("A", "B", "C")
s # => "ABCabc"
a = []
a.concat(["a"], ["b", "c"])
a # => ["a", "b", "c"]
Files
Updated by duerst (Martin Dürst) over 8 years ago
I think this can occasionally be helpful, and shouldn't be too difficult to implement. Can you provide a patch?
Updated by spinute (Satoru Horie) over 8 years ago
I will try to write a patch for it!
Updated by spinute (Satoru Horie) over 8 years ago
I have written a patch.
And, there are some points to ask
-
What is the appropriate behavior when calling concat/prepend without argument?
-
The code attached now returns just self
-
What should happen when writing ar.concat(ar, ar)?
-
ar = [1]; ar.concat(ar, ar) #=> [1,1,1]? or [1,1,1,1]?
-
ar << ar << ar returns [1,1,1,1], of course because this is just a sequence of binary operations
-
However, I feel "ar.concat(ar, ar)" saying "append present content of the array twice to the array", meaning [1,1,1]
-
The code attached returns [1,1,1,1], for now, just for the simplicity of implementation
Updated by spinute (Satoru Horie) over 8 years ago
I wrote another patch refined for a problem stated in a previous post.
It behaves like below
ar = [1]
ar.concat(ar, ar) #=> [1,1,1]
str = "ab"
str.concat(str, str) #=> "ababab"
Updated by sawa (Tsuyoshi Sawada) over 8 years ago
Satoru, thank you for the patch.
And you are making good points with the questions you raised.
- What is the appropriate behavior when calling concat/prepend without argument?
- The code attached now returns just self
I agree with this behavior. I think this would be the most natural.
- What should happen when writing ar.concat(ar, ar)?
- ar = [1]; ar.concat(ar, ar) #=> [1,1,1]? or [1,1,1,1]?
- ar << ar << ar returns [1,1,1,1], of course because this is just a sequence of binary operations
This is more logical (in some sense), but counter-intuitive.
- However, I feel "ar.concat(ar, ar)" saying "append present content of the array twice to the array", meaning [1,1,1]
This is more intuitive, but may be less logical.
I have preference with the second option, but am not completely sure. Maybe other people might have different opinions.
Updated by hsbt (Hiroshi SHIBATA) over 8 years ago
- Related to Feature #12247: accept multiple arguments at Array#delete added
Updated by matz (Yukihiro Matsumoto) over 8 years ago
Approved. I want to
ar = [1]
ar.concat(ar, ar)
to result [1,1,1]
.
Matz.
Updated by spinute (Satoru Horie) over 8 years ago
I added some test cases for Array#concat, String#concat and String#prepend and refined error handling.
Also, I fixed my code to conform to convention.
Any feedback is welcome!
Updated by nobu (Nobuyoshi Nakada) about 8 years ago
- Status changed from Open to Closed
Applied in changeset r56021.
multiple arguments
- array.c (rb_ary_concat_multi): take multiple arguments. based
on the patch by Satoru Horie. [Feature #12333] - string.c (rb_str_concat_multi, rb_str_prepend_multi): ditto.
Updated by stomar (Marcus Stollsteimer) over 7 years ago
- Related to Bug #13268: [DOC] Restore docs for String#<< added