Feature #5478

import Set into core, add syntax

Added by rkh (Konstantin Haase) over 8 years ago. Updated over 4 years ago.

Target version:


A set is a central data structure. However, a lot of Ruby developers use arrays for situations where it would be more reasonable to use a set. One reason for that is that it is way easier to use Array then Set at the moment, another one is that developers are simply not aware it exists.

I propose moving Set from the stdlib to core and possibly add a syntax or a method on array for creating Set literals.

First class syntax suggestions:

<1, 2, 3>  # might be tricky to parse
#[1, 2, 3] # would collide with comments
$[1, 2, 3]
${1, 2, 3}

Method suggestions:

~[1, 2, 3]
+[1, 2, 3]

Whitespace separated String Sets could look like this:

%w<foo bar blah> # creates an array at the moment 
#w[foo bar blah] # would collide with comments
$w[foo bar blah] # would collide with sending :[] to $w
$w{foo bar blah}

~%w[foo bar blah] # not really shorter than using an array with strings
+%w[foo bar balh] # not really shorter than using an array with strings

Maybe it's ok to not have a whitespace separated syntax, I'm just brainstorming here.

The issue with the method approach is that it would create an Array to send the message to first.

I favor the syntax, possibly without the ability to create a whitespace separated version.

I'd be willing to work on a patch not only for MRI but also for JRuby and Rubinius if you would consider this to be useful.
Although I would need help with the parser.

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