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

[Chris Lattner]

> On Feb 4, 2016, at 9:46 AM, Erica Sadun <erica at ericasadun.com> wrote:
> 
> What do you feel about something more like:
> 
> syntactic-context-statement → #setsyntaxcontext
> syntactic-context-statement → #setsyntaxcontext syntactic-control-assignments
> syntactic-control-assignments → syntactic-control-assignments, syntactic-control-assignment
> syntactic-control-assignments → syntactic-control-assignment
> syntactic-control-assignment → line = line-number
> syntactic-control-assignment → file = file-name
> syntactic-control-assignment → column = column-number
> syntactic-control-assignment → function = function-name
> syntactic-control-assignment → dsohandle = dsohandle-name

Something like this makes sense to me, but only file and line can really be set by this construct.

-Chris

> 
> -- E
> 
> 
>> On Feb 4, 2016, at 10:31 AM, Chris Lattner <clattner at apple.com <mailto:clattner at apple.com>> wrote:
>> 
>>> 
>>> On Feb 3, 2016, at 7:29 PM, Brent Royal-Gordon via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>> 
>>>> line-control-statement → #line­
>>>> line-control-statement → #line ­line-number­ file-name­
>>>> line-number → A decimal integer greater than zero
>>>> file-name → 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.
>>> 
>>> I don't love the way the current format has two unlabeled parameters in an arbitrary order. Maybe something more like this?
>>> 
>>> 	#reset line=50, file="foo.swift"
>>> 
>>> (I have a soft preference for "reset" over "set" because these are things the compiler changes automatically, but that might be a silly reason.)
>>> 
>>> Perhaps this could even let you set any combination of the #whatever parameters, so if, for instance, you were writing a parser generator, you could set #function to the name of the rule a particular piece of code came from.
>> 
>> Using something like this as the grammar structure makes sense to me, but I’d suggest something more specific (and longer) for this, perhaps:
>> 
>> #setsyntacticsourcelocation
>> 
>> or something. :-)
>> 
>> -Chris
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-evolution/attachments/20160204/29dd7b83/attachment.html>