[swift-evolution] [Review] SE-0144: Allow Single Dollar Sign as a Valid Identifier

[Charles Srstka]

> On Oct 14, 2016, at 2:59 PM, Chris Lattner via swift-evolution <swift-evolution at swift.org> wrote:
> 
> Hello Swift community,
> 
> The review of "SE-0144: Allow Single Dollar Sign as a Valid Identifier" begins now and runs through October 18. The proposal is available here:
> 
> 	https://github.com/apple/swift-evolution/blob/master/proposals/0144-allow-single-dollar-sign-as-valid-identifier.md
> 
> Reviews are an important part of the Swift evolution process. All reviews should be sent to the swift-evolution mailing list at
> 
> 	https://lists.swift.org/mailman/listinfo/swift-evolution
> 
> or, if you would like to keep your feedback private, directly to the review manager.
> 
> What goes into a review?
> 
> The goal of the review process is to improve the proposal under review through constructive criticism and contribute to the direction of Swift. When writing your review, here are some questions you might want to answer in your review:
> 
> 	* What is your evaluation of the proposal?
> 	* Is the problem being addressed significant enough to warrant a change to Swift?
> 	* Does this proposal fit well with the feel and direction of Swift?
> 	* If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?
> 	* How much effort did you put into your review? A glance, a quick reading, or an in-depth study?
> 
> More information about the Swift evolution process is available at
> 
> 	https://github.com/apple/swift-evolution/blob/master/process.md
> 
> Thank you,
> 
> -Chris Lattner
> Review Manager

> * What is your evaluation of the proposal?

-1. What is the point of this?

> * Is the problem being addressed significant enough to warrant a change to Swift?

The “problem” seems to be that one specific library misused a character that was not documented to be legal in an identifier. The solution would seem to be to fix the library, not change the language.

> * Does this proposal fit well with the feel and direction of Swift?

No, it does not. $ by itself looks far more like an operator than an identifier, and $ as the beginning of an identifier conflicts with the special $0, $1, etc. keywords that are already used by Swift.

> * If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?

The discussion of identifiers beginning with $ brings to mind Perl and similar scripting languages, in which scalar variables look like $foo, $bar, etc. I imagine that this is why $ was chosen for the $0, $1, etc. keywords. As a result, when seeing something like $foo in the language, one’s mind tends to interpret this as a variable named “foo” with the $ doing something to it, describing something about it, or something similar.

> * How much effort did you put into your review? A glance, a quick reading, or an in-depth study?

Read the proposal, read the thread.

Charles