Lua 5.5.0 is out!

[Fwirt]

Since Textadept stays up to date with newer Lua versions (unlike a lot of projects stuck on 5.1) this update actually brings a couple of nice features, in addition to making the language a little safer. Here's the complete "new feature" list from the readme page:

• declarations for global variables
• for-loop variables are read only
• floats are printed in decimal with enough digits to be read back correctly.
• more levels for constructors
• table.create
• utf8.offset returns also final position of character
• external strings (that use memory not managed by Lua)
• new functions luaL_openselectedlibs and luaL_makeseed
• major garbage collections done incrementally
• more compact arrays (large arrays use about 60% less memory)
• lua.c loads 'readline' dynamically
• static (fixed) binaries (when loading a binary chunk in memory, Lua can reuse its original memory in some of the internal structures)
• dump and undump reuse all strings
• auxiliary buffer reuses buffer when it creates final string

One thing that comes to mind for me is that the external strings feature would make it viable to use SCI_GETCHARACTERPOINTER/SCI_GETRANGEPOINTER for really fast buffer access without having to run a memcpy. But I don't know if it's worth the effort of implementing that.

From my cursory knowledge of the codebase and reading through the 5.4 incompatibilities I didn't see anything that is a major cause for concern as far as the upgrade goes.

[orbitalquark]

The issue with external strings is they need to be guaranteed to exist for the lifetime of any Lua variable assigned to them. Once Scintilla reallocs a character pointer for example, any Lua string references to an old pointer become invalid and can cause memory access errors.

Anyway, Textadept 13.0 alpha has an RC of Lua 5.5 for anyone that wants to try it out (the next alpha will have the final 5.5 version). I'm already taking advantage of the ...arg syntax for vararg tables. The main issue you may encounter when upgrading is that you cannot re-assign loop variables: for k in pairs(t) do k = k:lower(); print(k) end will result in an error. You should either use a new variable or put a local k = k for the loop variable in the body. I should probably add this to the migration guide.

[Fwirt]

Oh, they let you rename ... now? That's nice.

Yeah, that's what I figured about external strings. The reason it got my attention was because I've been hacking on implementing vi's move by section/paragraph/sentence/word commands and it's been a pain working with Scintilla's built-in regex. I feel like just iterating over the buffer would be easier, but I don't know if the overhead of calling buffer.char_at repeatedly is worse than the cstdlib's regex implementation...