HISTORY for Lua 5.1
* Changes from version 5.0 to 5.1
-------------------------------
Language:
+ new module system.
+ new semantics for control variables of fors.
+ new semantics for setn/getn.
+ new syntax/semantics for varargs.
+ new long strings and comments.
+ new `mod' operator (`%')
+ new length operator #t
+ metatables for all types
API:
+ new functions: lua_createtable, lua_get(set)field, lua_push(to)integer.
+ user supplies memory allocator (lua_open becomes lua_newstate).
+ luaopen_* functions must be called through Lua.
Implementation:
+ new configuration scheme via luaconf.h.
+ incremental garbage collection.
+ better handling of end-of-line in the lexer.
+ fully reentrant parser (new Lua function `load')
+ better support for 64-bit machines.
+ native loadlib support for Mac OS X.
+ standard distribution in only one library (lualib.a merged into lua.a)
* Changes from version 4.0 to 5.0
-------------------------------
Language:
+ lexical scoping.
+ Lua coroutines.
+ standard libraries now packaged in tables.
+ tags replaced by metatables and tag methods replaced by metamethods,
stored in metatables.
+ proper tail calls.
+ each function can have its own global table, which can be shared.
+ new __newindex metamethod, called when we insert a new key into a table.
+ new block comments: --[[ ... ]].
+ new generic for.
+ new weak tables.
+ new boolean type.
+ new syntax "local function".
+ (f()) returns the first value returned by f.
+ {f()} fills a table with all values returned by f.
+ \n ignored in [[\n .
+ fixed and-or priorities.
+ more general syntax for function definition (e.g. function a.x.y:f()...end).
+ more general syntax for function calls (e.g. (print or write)(9)).
+ new functions (time/date, tmpfile, unpack, require, load*, etc.).
API:
+ chunks are loaded by using lua_load; new luaL_loadfile and luaL_loadbuffer.
+ introduced lightweight userdata, a simple "void*" without a metatable.
+ new error handling protocol: the core no longer prints error messages;
all errors are reported to the caller on the stack.
+ new lua_atpanic for host cleanup.
+ new, signal-safe, hook scheme.
Implementation:
+ new license: MIT.
+ new, faster, register-based virtual machine.
+ support for external multithreading and coroutines.
+ new and consistent error message format.
+ the core no longer needs "stdio.h" for anything (except for a single
use of sprintf to convert numbers to strings).
+ lua.c now runs the environment variable LUA_INIT, if present. It can
be "@filename", to run a file, or the chunk itself.
+ support for user extensions in lua.c.
sample implementation given for command line editing.
+ new dynamic loading library, active by default on several platforms.
+ safe garbage-collector metamethods.
+ precompiled bytecodes checked for integrity (secure binary dostring).
+ strings are fully aligned.
+ position capture in string.find.
+ read('*l') can read lines with embedded zeros.
* Changes from version 3.2 to 4.0
-------------------------------
Language:
+ new "break" and "for" statements (both numerical and for tables).
+ uniform treatment of globals: globals are now stored in a Lua table.
+ improved error messages.
+ no more '$debug': full speed *and* full debug information.
+ new read form: read(N) for next N bytes.
+ general read patterns now deprecated.
(still available with -DCOMPAT_READPATTERNS.)
+ all return values are passed as arguments for the last function
(old semantics still available with -DLUA_COMPAT_ARGRET)
+ garbage collection tag methods for tables now deprecated.
+ there is now only one tag method for order.
API:
+ New API: fully re-entrant, simpler, and more efficient.
+ New debug API.
Implementation:
+ faster than ever: cleaner virtual machine and new hashing algorithm.
+ non-recursive garbage-collector algorithm.
+ reduced memory usage for programs with many strings.
+ improved treatment for memory allocation errors.
+ improved support for 16-bit machines (we hope).
+ code now compiles unmodified as both ANSI C and C++.
+ numbers in bases other than 10 are converted using strtoul.
+ new -f option in Lua to support #! scripts.
+ luac can now combine text and binaries.
* Changes from version 3.1 to 3.2
-------------------------------
+ redirected all output in Lua's core to _ERRORMESSAGE and _ALERT.
+ increased limit on the number of constants and globals per function
(from 2^16 to 2^24).
+ debugging info (lua_debug and hooks) moved into lua_state and new API
functions provided to get and set this info.
+ new debug lib gives full debugging access within Lua.
+ new table functions "foreachi", "sort", "tinsert", "tremove", "getn".
+ new io functions "flush", "seek".
* Changes from version 3.0 to 3.1
-------------------------------
+ NEW FEATURE: anonymous functions with closures (via "upvalues").
+ new syntax:
- local variables in chunks.
- better scope control with DO block END.
- constructors can now be also written: { record-part; list-part }.
- more general syntax for function calls and lvalues, e.g.:
f(x).y=1
o:f(x,y):g(z)
f"string" is sugar for f("string")
+ strings may now contain arbitrary binary data (e.g., embedded zeros).
+ major code re-organization and clean-up; reduced module interdependecies.
+ no arbitrary limits on the total number of constants and globals.
+ support for multiple global contexts.
+ better syntax error messages.
+ new traversal functions "foreach" and "foreachvar".
+ the default for numbers is now double.
changing it to use floats or longs is easy.
+ complete debug information stored in pre-compiled chunks.
+ sample interpreter now prompts user when run interactively, and also
handles control-C interruptions gracefully.
* Changes from version 2.5 to 3.0
-------------------------------
+ NEW CONCEPT: "tag methods".
Tag methods replace fallbacks as the meta-mechanism for extending the
semantics of Lua. Whereas fallbacks had a global nature, tag methods
work on objects having the same tag (e.g., groups of tables).
Existing code that uses fallbacks should work without change.
+ new, general syntax for constructors {[exp] = exp, ... }.
+ support for handling variable number of arguments in functions (varargs).
+ support for conditional compilation ($if ... $else ... $end).
+ cleaner semantics in API simplifies host code.
+ better support for writing libraries (auxlib.h).
+ better type checking and error messages in the standard library.
+ luac can now also undump.
* Changes from version 2.4 to 2.5
-------------------------------
+ io and string libraries are now based on pattern matching;
the old libraries are still available for compatibility
+ dofile and dostring can now return values (via return statement)
+ better support for 16- and 64-bit machines
+ expanded documentation, with more examples
* Changes from version 2.2 to 2.4
-------------------------------
+ external compiler creates portable binary files that can be loaded faster
+ interface for debugging and profiling
+ new "getglobal" fallback
+ new functions for handling references to Lua objects
+ new functions in standard lib
+ only one copy of each string is stored
+ expanded documentation, with more examples
* Changes from version 2.1 to 2.2
-------------------------------
+ functions now may be declared with any "lvalue" as a name
+ garbage collection of functions
+ support for pipes
* Changes from version 1.1 to 2.1
-------------------------------
+ object-oriented support
+ fallbacks
+ simplified syntax for tables
+ many internal improvements
(end of HISTORY)
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