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)