cmtice wrote: > > If it's possible, it would be nice to have one actual release where people > > who used this form of range access will get an error. That will be easy to > > detect in any scripts folks are currently using, and easy to fix. However, > > if the first official release of this goes from treating it as a range to > > treating the difference as an index, that would causes errors that will be > > much harder to detect. The other way to do this is add an experimental > > setting (so we can delete it later) that enables "- is always minus" (and > > returns an error for the token otherwise) and ship it off. That would mean > > the error detection would still happen. Since people are going to have to > > find out that this is supported to use it anyway, provided we mention the > > setting in the same docs, this shouldn't cause any problems. After a > > release, we can delete the setting and unconditionally allow the behavior. > > @jimingham I agree that people should be warned first, but there is a problem > here is that once I add binary minus, the parser won't be able to distinguish > between a minus as a separator compared to a minus as a part of an expression > in this part: > > ``` > postfix_expression "[" expression "]" > postfix_expression "[" expression "-" expression "]" > ``` > > So I'll have to change the `expression` here to something below the binary > minus in the grammar, like a `unary_expression` or another > `postfix_expression`. > > I can make this change in this patch along with an error upon finding '-' > that suggests to use `:` instead. When I add binary minus I will also add the > "- is always minus" setting, which we can remove 2 releases from now, I > guess? The only downside is that the expressions available for indexing will > be limited for all this time.
Can't you just update the code that currently recognizes "[expr - expr]" to return an error for now (something along the lines that "this syntax is deprecated; please use ':' instead of '-'")? Then in the PR that implements binary subtraction, remove this error message? https://github.com/llvm/llvm-project/pull/173410 _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
