Feature #15983: Can we have a similar syntax (string interpolation) the way V language has?

• Status: Rejected
• Assignee: -
• Target version: -

[mechanicles (Santosh Wadghule)]

Sorry, guys, This is the first feature that I am writing in this Ruby issue tracking system, and If I make any mistake, please understand :).

Today I was going through this language, i.e. V language (mainly their website) and found its basic code like below,

fn main() {
	areas := ['game', 'web', 'tools', 'science', 'systems',
	          'embedded', 'GUI', 'mobile'] 
	for area in areas {
		println('Hello, $area developers!')
	}
}

I like this kind of string interpolation which looks so simple to write. If we try to write the same code in Ruby, we need to write like this,

areas = ['game', 'web', 'science', 'system']

areas.each do |area|
  puts "Hello, #{area} developers!"
end

Instead of using #{area} syntax for string interpolation, can we have something like $area? This might save some keystrokes.

I know that Ruby has already occupied this $ character. But we can use another character which is not used in Ruby.

We can close this feature request if we already discussed on such topic before.

[duerst (Martin Dürst)]

There are other languages that use $ in string interpolation. One of them is Perl. Perl is much more famous and widely used than V. Ruby was created as a better Perl. $variable_name may work (most of the time, but not always) in languages with spaces between words, but it doesn't work well in a language that's written without spaces, such as Japanese. My guess is that this is one of the reasons for why Matz choose an explicit terminator ('}') for interpolations.

[shevegen (Robert A. Heiler)]

Let's look at this purely from a syntax point of view first, so that we can avoid
other issues such as backwards incompatible changes (which may be a big reason
why this request will not be implemented; but you have to ask matz).

I think you have made a good point that e. g.

$foo = 'world'

puts "hello $foo"

would be simpler to type than e. g.

puts "hello #{$foo}"

or

foo = 'world'

puts "hello #{foo}"

Actually, for global variables this is already possible and has been
for many years; for @instance_variables this also seems to work... I
thought it would not work but I just tested this:

@foo = 'world'

puts "hello #@foo"

And that works.

Martin pointed out that Perl allows for string interpolation like that,
although it still seems different to this behaviour:

areas := ['game', 'web', 'tools'] 

for area in areas {

    println('Hello, $area developers!')

Since we do not need special access modifiers for the variable "areas",
whereas I seem to remember in perl we had to use some identifier
such as $areas or something like that; or @areas or something (it
has been literally like almost +15 years since I last wrote perl
code ...).

Having said that, I think that it is probably not easily doable to
interpolate without #{} for non-global variables, as otherwise
it might have been done yet.

Adding another syntax identifier as proposed, would, in my opinion,
not be a good idea, since the scope of the change is motivated
primarily by the possibility to avoid #{} only. #{} can be annoying,
but having to add a new character solely for this would be bad as
well, I think. Then there is also the issue of backwards compatibility,
so I think while it is an interesting idea, it is most likely not
a very realistic one. But that is just my opinion - ultimately you
have to ask matz. :)

[ko1 (Koichi Sasada)]

• Status changed from Open to Rejected

I know that Ruby has already occupied this $ character. But we can use another character which is not used in Ruby.

Please make new ticket if you have good character instead of $.

Thanks.