New Array Methods idea

Ruby
1

So granted I’ve ventured over to Lisp land a bit, but these ideas still
seem like they could be useful:

array = [1, 2, 3, 4, 5]

Exists

array.first # => 1

Proposed

array.rest # => [2, 3, 4, 5]

…and/or array.tail

Granted it would be as simple as array[1…-1] but that lacks the
distinct
eloquence of most ruby syntax and it seems to be far more of a language
feature possibility.

Monkey patching it on would be trivial, yes, but I would rather avoid
that
in favor of discussing this as a possible feature.

This of course inspired by Lisp’s car/cdr or first/rest and head/tail
(of
which I don’t remember the origin.)

Any thoughts on this idea?

2

On 11/08/2013 10:34 PM, Brandon W. wrote:

…and/or array.tail

Any thoughts on this idea?

Yes, please. I use array[1..-1] all the time and it feels cumbersome.

Looks like there is a proposal, although it has not been touched in just
over a year: Feature #6727: Add Array#rest (with implementation) - Ruby master - Ruby Issue Tracking System

-Justin

3

Justin C. wrote in post #1126807:

On 11/08/2013 10:34 PM, Brandon W. wrote:

…and/or array.tail

Why not

array.drop(1)

_md

4

On Sun, Nov 10, 2013 at 12:46 AM, Brandon W.
[email protected] wrote:

It doesn’t fit the feel of Ruby, and isn’t nearly as expressive or succinct
as what I mentioned above.

ruby is not lisp.

try eg,

array.shift #=> 1
array #=> [2, 3, 4, 5]

kind regards -botp

5

“Some may say Ruby is a bad rip-off of Lisp or Smalltalk, and I admit
that.
But it is nicer to ordinary people.”

  • Matz, LL2

Ruby is a language designed in the following steps:

  • take a simple lisp language (like one prior to CL).
  • remove macros, s-expression.
  • add simple object system (much simpler than CLOS).
  • add blocks, inspired by higher order functions.
  • add methods found in Smalltalk.
  • add functionality found in Perl (in OO way).

So, Ruby was a Lisp originally, in theory.
Let’s call it MatzLisp from now on. :wink:

  • Matz

About that…

6

It doesn’t fit the feel of Ruby, and isn’t nearly as expressive or
succinct
as what I mentioned above.

7

On Nov 9, 2013, at 11:26 AM, Brandon W. [email protected]
wrote:

  • add methods found in Smalltalk.

array.shift #=> 1
array #=> [2, 3, 4, 5]

kind regards -botp

All interesting and such, but moot given core language change
discussions happens over on ruby-core mailing list. I think your
suggestion has merit (Hey, Im a Lisper, too!), but nothing we can really
do over here. Even better, fork ruby, add the methods, and submit a PR.
Id say it should be in Enumerable, as well. The implementation should be
dead-easy:

class Array
def rest(n=1)
self.drop(n)
end
end

8

Someone already did, and I did actually go straight to that list. The
request is there and is about a year old so I was stirring it up a bit
after I found the report to add it.

9

On Nov 9, 2013, at 5:50 PM, Brandon W. [email protected]
wrote:

Someone already did, and I did actually go straight to that list. The request is
there and is about a year old so I was stirring it up a bit after I found the
report to add it.

Cool beans :slight_smile:

10

I use Arrays with “headers” quite a lot, so I think this is an excellent
idea :slight_smile:

11

Also:

a = [1,2,3,4,5]
first, *rest = a
first # => 1
rest # => [2, 3, 4, 5]