On 06/07/2015 23:52, Karl Berry wrote: > we would like input on how a transition to new support code > can be managed. > > Forgive the naive question, but is it viable to make the ltluatex code > not actually break loading the existing packages? I mean, if a document > using the existing packages can go right on using them in the presence > of ltluatex, then all seems well to me. If that's not possible, it > seems to me that every existing lualatex document will require changing. > Which seems obviously undesirable, if, I suppose, just barely possible > at this point. > > k > Yes anything's possible (and we gave the maintainers of luatex/luatexbase an advance copy of this and we've bounced some ideas around) but it's not cast in stone yet. For a start the majority of documents don't load luatexbase.sty/luatex.sty directly, they load fontspec to get the fonts and thus load luatexbase via that. Fontspec obviously needs to work. So it will not be the case that "every existing lualatex" document will need changing, far from it. For documents that are explicitly loading luatexbase then there would be decisions to be made as to whether luatexbase should detect a new format and quit or whether it should over-ride the new code and do what it always did, or whether it should emulate any extra features that it used to provide, but implemented now over the new format code. However whichever one of those is chosen (and primarily that's a choice for the existing package maintainers) I would expect the overwhelming majority of documents to work unchanged. (package updates may be necessary or desirable) One reason for making the draft public in this raw state is to allow more people to experiment with real documents and check all features are covered. tex being tex there will probably be some edge cases where document change is required, but with luatex that happens anyway as the underlying engine and lua language are not cast in stone the way tex3 is. David ________________________________ The Numerical Algorithms Group Ltd is a company registered in England and Wales with company number 1249803. The registered office is: Wilkinson House, Jordan Hill Road, Oxford OX2 8DR, United Kingdom. This e-mail has been scanned for all viruses by Microsoft Office 365. ________________________________