Slight rework, add plan as stated by Neil Bowers in comment as part of specification. Split up core/dual-life issues

Author: nicomen

rfcs/rfc0015.md

@@ -24,11 +24,7 @@ From perldoc perlmod
 * We have been warning against its usage for decades.
 * It was there merely for easier adoption, but has been used very little.
 
-## Specification
-
-## Backwards Compatibility
-
-## Open Issues
+## Alternatives
 
 There are a few alternatives on how to disable this feature and changing the meaning of `'`
 
@@ -71,21 +67,39 @@ $ perl -wlE 'sub foo'"'"'bar { "lol"; }; print foo'"'"'bar();'
 lol
 ```
 
+## Specification
+
+The feature should be rolled out in two steps, in two consecutive Perl stable releases
+
+1. Add warning code to apostrophe usage in identifiers (outside of string interpolation) (alternative `4`) (as has been done for string interpolation already (alternative `c`)) [6]
+
+2. Syntax error when using apostrophe as part of identifiers outside strings (alternative `b`), treat apostrophes inside strings as not a part of a variable when interpolating (alternative `1`) 
+
+## Backwards Compatibility
+
+This change will break backwards compatibility in two stable releases
+
 ### Known core / dual-life modules utilizing apostrophe as separator
 
+The following issues are slowly being sorted out independently of this RFC. 
+
 * ~~cpan/Term-Cap `isn't` in test [trivial to replace] https://github.com/jonathanstowe/Term-Cap/pull/13~~ [fixed]
 * ~~dist/PathTools `isn't` in test [trivial to replace] https://github.com/Perl/perl5/pull/19865~~ [fixed]
 * cpan/autodie test in Klingon [not THAT trivial to replace, don't know Klingon] https://github.com/pjf/autodie/issues/115
+
+The following issues might need to synchronize with the perl releases by checking versions or feature flags 
+
 * ~~cpan/Test-Simple `isn::t` [would work wth 2 + b with small change, or state compatibility in docs]~~ [fixed] https://github.com/Test-More/test-more/commit/d619c1b0486422ac86b6c870241bf6138a041a8f
 * cpan/Scalar-List-Utils `set_subname` implementation [need to check perl version in .xs code etc]
 
 ## References
 
-* Old package separator syntax #16270 (rt.perl.org#132485) https://github.com/Perl/perl5/issues/16270 
-* Discussion from 2009 at perl5-porters: https://markmail.org/message/gaux5xx5jlop3vmk
-* Discussion from 2017 at perl5-porters: https://markmail.org/message/ffmc2k3xafhwajys
-* Discussion from 2021 at perl5-porters: https://markmail.org/message/hms4gy4okkgvnk23
-* Simple grep of `isn't` usage on CPAN: `https://grep.metacpan.org/search?q=%5E%5Cs*isn%27t%7Cisn%27t%5Cs*%5B%28%24%40%25%5D&qd=&qft=*.t` (Note that there quite a few false positives, so I'd guess more like 30 pkgs)
+* [1] Old package separator syntax #16270 (rt.perl.org#132485) https://github.com/Perl/perl5/issues/16270 
+* [2] Discussion from 2009 at perl5-porters: https://markmail.org/message/gaux5xx5jlop3vmk
+* [3] Discussion from 2017 at perl5-porters: https://markmail.org/message/ffmc2k3xafhwajys
+* [4] Discussion from 2021 at perl5-porters: https://markmail.org/message/hms4gy4okkgvnk23
+* [5] Simple grep of `isn't` usage on CPAN: `https://grep.metacpan.org/search?q=%5E%5Cs*isn%27t%7Cisn%27t%5Cs*%5B%28%24%40%25%5D&qd=&qft=*.t` (Note that there quite a few false positives, so I'd guess more like 30 pkgs)
+* [6] Father Chrysostomos added a warning when used apostrophes are used inside string within a variable name: https://github.com/Perl/perl5/commit/2cb35ee012cfe486aa75a422e7bb3cb18ff51336
 
 ## Conditions to test