Changes since Lua 5.4

Here are the main changes introduced in Lua 5.5. The reference manual lists the incompatibilities that had to be introduced.

Main changes

• declarations for global variables
• named vararg tables
• 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