[swift-evolution] [Discussion]: Renaming #line, the line control statement

[Greg Parker]

I like something that has a verb. We don't expect humans to write this directive, so we should optimize to prevent accidental use of this where you really wanted #line. #setline is better than #sourceline by that metric.

> On Feb 3, 2016, at 6:54 PM, Kevin Ballard via swift-evolution <swift-evolution at swift.org> wrote:
> 
> I'm in favor of #setline. It has as nice match to #line because #setline changes the value that #line returns.
>  
> -Kevin Ballard
>  
> On Wed, Feb 3, 2016, at 06:19 PM, Erica Sadun via swift-evolution wrote:
>> #source is already earmarked for future directions.
>>  
>> I'm thinking #setline and #sourceline are both good.
>>  
>>> On Feb 3, 2016, at 6:58 PM, Sean Heber <sean at fifthace.com <mailto:sean at fifthace.com>> wrote:
>>>  
>>> I like that reasoning. I'd suggest even simpler and go with #source since it also can include a file name.
>>>  
>>> l8r
>>> Sean
>>>  
>>> Sent from my iPad
>>>  
>>> On Feb 3, 2016, at 7:32 PM, Jonathan Tang via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>>> The primary use for the existing #line directive is for generated code like parser/lexer generators, right?  If so, how about #sourceline, since it represents the line number in the original source code?  I'm also fine with #setline, but don't like #linenumber because it's not clear what the difference is between it and #line.
>>>>  
>>>> Actually, it'd also be used to reset the line number back to the generated code, right?  In that case, #sourceline seems awkward, and maybe I'll just go with +1 to #setline.
>>>>  
>>>> On Wed, Feb 3, 2016 at 5:24 PM, Erica Sadun via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>>> Swift Evolution SE-0028 (https://github.com/apple/swift-evolution/blob/master/proposals/0028-modernizing-debug-identifiers.md <https://github.com/apple/swift-evolution/blob/master/proposals/0028-modernizing-debug-identifiers.md>) overloads
>>>> the use of #line to mean both an identifier that maps to a calling site's line number with a file and acts as part of a line control statement with the following grammar:
>>>>  
>>>> line-control-statement → #line­
>>>>  <>line-control-statement → #line­line-number <https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/line-number>­file-name <https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/file-name>­
>>>>  <>line-number → A decimal integer greater than zero
>>>>  <>file-name → static-string-literal <https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/LexicalStructure.html#//apple_ref/swift/grammar/static-string-literal>­
>>>>  
>>>> The accepted implementation of SE-0028 disambiguates the two by requiring #line (the control statement) to appear at the first column for the time being. This is a stop-gap solution best remedied by renaming #line. 
>>>>  
>>>> Chris Lattner writes, "The core team isn’t thrilled with the magic “first token on a line” whitespace behavior that #line will be getting, and would like someone to start a discussion about renaming the old #line directive to something more specific and tailored to its purpose.   Once that name and syntax is settled, we can rename the directive and remove the whitespace rule."
>>>>  
>>>> I'd recommend #setline or #linenumber. Starting this thread to solicit other suggestions.
>>>>  
>>>> Best, -- E
>>>>  
>>>>  
>>>> _______________________________________________
>>>> swift-evolution mailing list
>>>> swift-evolution at swift.org <mailto:swift-evolution at swift.org>
>>>> https://lists.swift.org/mailman/listinfo/swift-evolution <https://lists.swift.org/mailman/listinfo/swift-evolution>
>>>>  
>>>> _______________________________________________
>>>> swift-evolution mailing list
>>>> swift-evolution at swift.org <mailto:swift-evolution at swift.org>
>>>> https://lists.swift.org/mailman/listinfo/swift-evolution <https://lists.swift.org/mailman/listinfo/swift-evolution>
>> 
>> _______________________________________________
>> swift-evolution mailing list
>> swift-evolution at swift.org <mailto:swift-evolution at swift.org>
>> https://lists.swift.org/mailman/listinfo/swift-evolution <https://lists.swift.org/mailman/listinfo/swift-evolution>
>  
> _______________________________________________
> swift-evolution mailing list
> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-evolution/attachments/20160203/5edf68cd/attachment.html>