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31<H1>
32<A HREF="http://www.lua.org/"><IMG SRC="logo.gif" ALT="Lua" BORDER=0></A>
33Welcome to Lua 5.2
34</H1>
35
36<P>
37<A HREF="#about">about</A>
38·
39<A HREF="#install">installation</A>
40·
41<A HREF="#changes">changes</A>
42·
43<A HREF="#license">license</A>
44·
45<A HREF="contents.html">reference manual</A>
46
47<H2><A NAME="about">About Lua</A></H2>
48
49<P>
50Lua is a powerful, fast, lightweight, embeddable scripting language
51developed by a
52<A HREF="http://www.lua.org/authors.html">team</A>
53at
54<A HREF="http://www.puc-rio.br/">PUC-Rio</A>,
55the Pontifical Catholic University of Rio de Janeiro in Brazil.
56Lua is
57<A HREF="#license">free software</A>
58used in many products and projects around the world.
59
60<P>
61Lua's
62<A HREF="http://www.lua.org/">official web site</A>
63provides complete information
64about Lua,
65including
66an
67<A HREF="http://www.lua.org/about.html">executive summary</A>
68and
69updated
70<A HREF="http://www.lua.org/docs.html">documentation</A>,
71especially the
72<A HREF="http://www.lua.org/manual/5.2/">reference manual</A>,
73which may differ slightly from the
74<A HREF="contents.html">local copy</A>
75distributed in this package.
76
77<H2><A NAME="install">Installing Lua</A></H2>
78
79<P>
80Lua is distributed in
81<A HREF="http://www.lua.org/ftp/">source</A>
82form.
83You need to build it before using it.
84Building Lua should be straightforward
85because
86Lua is implemented in pure ANSI C and compiles unmodified in all known
87platforms that have an ANSI C compiler.
88Lua also compiles unmodified as C++.
89The instructions given below for building Lua are for Unix-like platforms.
90See also
91<A HREF="#other">instructions for other systems</A>
92and
93<A HREF="#customization">customization options</A>.
94
95<P>
96If you don't have the time or the inclination to compile Lua yourself,
97get a binary from
98<A HREF="http://lua-users.org/wiki/LuaBinaries">LuaBinaries</A>.
99Try also
100<A HREF="http://luaforwindows.luaforge.net/">Lua for Windows</A>,
101an easy-to-use distribution of Lua that includes many useful libraries.
102
103<H3>Building Lua</H3>
104
105<P>
106In most Unix-like platforms, simply do "<KBD>make</KBD>" with a suitable target.
107Here are the details.
108
109<OL>
110<LI>
111Open a terminal window and move to
112the top-level directory, which is named <TT>lua-5.2.2</TT>.
113The Makefile there controls both the build process and the installation process.
114<P>
115<LI>
116 Do "<KBD>make</KBD>" and see if your platform is listed.
117 The platforms currently supported are:
118<P>
119<P CLASS="display">
120 aix ansi bsd freebsd generic linux macosx mingw posix solaris
121</P>
122<P>
123 If your platform is listed, just do "<KBD>make xxx</KBD>", where xxx
124 is your platform name.
125<P>
126 If your platform is not listed, try the closest one or posix, generic,
127 ansi, in this order.
128<P>
129<LI>
130The compilation takes only a few moments
131and produces three files in the <TT>src</TT> directory:
132lua (the interpreter),
133luac (the compiler),
134and liblua.a (the library).
135<P>
136<LI>
137 To check that Lua has been built correctly, do "<KBD>make test</KBD>"
138 after building Lua. This will run the interpreter and print its version string.
139</OL>
140<P>
141If you're running Linux and get compilation errors,
142make sure you have installed the <TT>readline</TT> development package.
143If you get link errors after that,
144then try "<KBD>make linux MYLIBS=-ltermcap</KBD>".
145
146<H3>Installing Lua</H3>
147<P>
148 Once you have built Lua, you may want to install it in an official
149 place in your system. In this case, do "<KBD>make install</KBD>". The official
150 place and the way to install files are defined in the Makefile. You'll
151 probably need the right permissions to install files.
152
153<P>
154 To build and install Lua in one step, do "<KBD>make xxx install</KBD>",
155 where xxx is your platform name.
156
157<P>
158 To install Lua locally, do "<KBD>make local</KBD>".
159 This will create a directory <TT>install</TT> with subdirectories
160 <TT>bin</TT>, <TT>include</TT>, <TT>lib</TT>, <TT>man</TT>,
161 and install Lua as listed below.
162
163 To install Lua locally, but in some other directory, do
164 "<KBD>make install INSTALL_TOP=xxx</KBD>", where xxx is your chosen directory.
165
166<DL CLASS="display">
167<DT>
168 bin:
169<DD>
170 lua luac
171<DT>
172 include:
173<DD>
174 lua.h luaconf.h lualib.h lauxlib.h lua.hpp
175<DT>
176 lib:
177<DD>
178 liblua.a
179<DT>
180 man/man1:
181<DD>
182 lua.1 luac.1
183</DL>
184
185<P>
186 These are the only directories you need for development.
187 If you only want to run Lua programs,
188 you only need the files in bin and man.
189 The files in include and lib are needed for
190 embedding Lua in C or C++ programs.
191
192<H3><A NAME="customization">Customization</A></H3>
193<P>
194 Three kinds of things can be customized by editing a file:
195<UL>
196 <LI> Where and how to install Lua — edit <TT>Makefile</TT>.
197 <LI> How to build Lua — edit <TT>src/Makefile</TT>.
198 <LI> Lua features — edit <TT>src/luaconf.h</TT>.
199</UL>
200
201<P>
202 You don't actually need to edit the Makefiles because you may set the
203 relevant variables in the command line when invoking make.
204 Nevertheless, it's probably best to edit and save the Makefiles to
205 record the changes you need.
206
207<P>
208 On the other hand, if you need to customize some Lua features, you'll need
209 to edit <TT>src/luaconf.h</TT> before building and installing Lua.
210 The edited file will be the one installed, and
211 it will be used by any Lua clients that you build, to ensure consistency.
212 Further customization is available to experts by editing the Lua sources.
213
214<P>
215 We strongly recommend that you enable dynamic loading in <TT>src/luaconf.h</TT>.
216 This is done automatically for all platforms listed above that have
217 this feature and also for Windows.
218
219<H3><A NAME="other">Building Lua on other systems</A></H3>
220
221<P>
222 If you're not using the usual Unix tools, then the instructions for
223 building Lua depend on the compiler you use. You'll need to create
224 projects (or whatever your compiler uses) for building the library,
225 the interpreter, and the compiler, as follows:
226
227<DL CLASS="display">
228<DT>
229library:
230<DD>
231lapi.c lcode.c lctype.c ldebug.c ldo.c ldump.c lfunc.c lgc.c llex.c
232lmem.c lobject.c lopcodes.c lparser.c lstate.c lstring.c ltable.c
233ltm.c lundump.c lvm.c lzio.c
234lauxlib.c lbaselib.c lbitlib.c lcorolib.c ldblib.c liolib.c
235lmathlib.c loslib.c lstrlib.c ltablib.c loadlib.c linit.c
236<DT>
237interpreter:
238<DD>
239 library, lua.c
240<DT>
241compiler:
242<DD>
243 library, luac.c
244</DL>
245
246<P>
247 To use Lua as a library in your own programs you'll need to know how to
248 create and use libraries with your compiler. Moreover, to dynamically load
249 C libraries for Lua you'll need to know how to create dynamic libraries
250 and you'll need to make sure that the Lua API functions are accessible to
251 those dynamic libraries — but <EM>don't</EM> link the Lua library
252 into each dynamic library. For Unix, we recommend that the Lua library
253 be linked statically into the host program and its symbols exported for
254 dynamic linking; <TT>src/Makefile</TT> does this for the Lua interpreter.
255 For Windows, we recommend that the Lua library be a DLL.
256
257<P>
258 As mentioned above, you may edit <TT>src/luaconf.h</TT> to customize
259 some features before building Lua.
260
261<H2><A NAME="changes">Changes since Lua 5.1</A></H2>
262
263<P>
264Here are the main changes introduced in Lua 5.2.
265The
266<A HREF="contents.html">reference manual</A>
267lists the
268<A HREF="manual.html#8">incompatibilities</A> that had to be introduced.
269
270<H3>Main changes</H3>
271<UL>
272<LI> yieldable pcall and metamethods
273<LI> new lexical scheme for globals
274<LI> ephemeron tables
275<LI> new library for bitwise operations
276<LI> light C functions
277<LI> emergency garbage collector
278<LI> <CODE>goto</CODE> statement
279<LI> finalizers for tables
280</UL>
281
282Here are the other changes introduced in Lua 5.2:
283<H3>Language</H3>
284<UL>
285<LI> no more fenv for threads or functions
286<LI> tables honor the <CODE>__len</CODE> metamethod
287<LI> hex and <CODE>\z</CODE> escapes in strings
288<LI> support for hexadecimal floats
289<LI> order metamethods work for different types
290<LI> no more verification of opcode consistency
291<LI> hook event "tail return" replaced by "tail call"
292<LI> empty statement
293<LI> <CODE>break</CODE> statement may appear in the middle of a block
294</UL>
295
296<H3>Libraries</H3>
297<UL>
298<LI> arguments for function called through <CODE>xpcall</CODE>
299<LI> optional 'mode' argument to load and loadfile (to control binary x text)
300<LI> optional 'env' argument to load and loadfile (environment for loaded chunk)
301<LI> <CODE>loadlib</CODE> may load libraries with global names (RTLD_GLOBAL)
302<LI> new function <CODE>package.searchpath</CODE>
303<LI> modules receive their paths when loaded
304<LI> optional base in <CODE>math.log</CODE>
305<LI> optional separator in <CODE>string.rep</CODE>
306<LI> <CODE>file:write</CODE> returns <CODE>file</CODE>
307<LI> closing a pipe returns exit status
308<LI> <CODE>os.exit</CODE> may close state
309<LI> new metamethods <CODE>__pairs</CODE> and <CODE>__ipairs</CODE>
310<LI> new option 'isrunning' for <CODE>collectgarbage</CODE> and <CODE>lua_gc</CODE>
311<LI> frontier patterns
312<LI> <CODE>\0</CODE> in patterns
313<LI> new option <CODE>*L</CODE> for <CODE>io.read</CODE>
314<LI> options for <CODE>io.lines</CODE>
315<LI> <CODE>debug.getlocal</CODE> can access function varargs
316</UL>
317
318<H3>C API</H3>
319<UL>
320<LI> main thread predefined in the registry
321<LI> new functions
322<CODE>lua_absindex</CODE>,
323<CODE>lua_arith</CODE>,
324<CODE>lua_compare</CODE>,
325<CODE>lua_copy</CODE>,
326<CODE>lua_len</CODE>,
327<CODE>lua_rawgetp</CODE>,
328<CODE>lua_rawsetp</CODE>,
329<CODE>lua_upvalueid</CODE>,
330<CODE>lua_upvaluejoin</CODE>,
331<CODE>lua_version</CODE>.
332<LI> new functions
333<CODE>luaL_checkversion</CODE>,
334<CODE>luaL_setmetatable</CODE>,
335<CODE>luaL_testudata</CODE>,
336<CODE>luaL_tolstring</CODE>.
337<LI> <CODE>lua_pushstring</CODE> and <CODE>pushlstring</CODE> return string
338<LI> <CODE>nparams</CODE> and <CODE>isvararg</CODE> available in debug API
339<LI> new <CODE>lua_Unsigned</CODE>
340</UL>
341
342<H3>Implementation</H3>
343<UL>
344<LI> max constants per function raised to 2<SUP>26</SUP>
345<LI> generational mode for garbage collection (experimental)
346<LI> NaN trick (experimental)
347<LI> internal (immutable) version of ctypes
348<LI> simpler implementation for string buffers
349<LI> parser uses much less C-stack space (no more auto arrays)
350</UL>
351
352<H3>Lua standalone interpreter</H3>
353<UL>
354<LI> new <CODE>-E</CODE> option to avoid environment variables
355<LI> handling of non-string error messages
356</UL>
357
358<H2><A NAME="license">License</A></H2>
359<A HREF="http://www.opensource.org/docs/definition.php">
360<IMG SRC="osi-certified-72x60.png" ALIGN="right" BORDER="0" ALT="[osi certified]" STYLE="padding-left: 30px ;">
361</A>
362
363<P>
364Lua is free software distributed under the terms of the
365<A HREF="http://www.opensource.org/licenses/mit-license.html">MIT license</A>
366reproduced below;
367it may be used for any purpose, including commercial purposes,
368at absolutely no cost without having to ask us.
369
370The only requirement is that if you do use Lua,
371then you should give us credit by including the appropriate copyright notice somewhere in your product or its documentation.
372
373For details, see
374<A HREF="http://www.lua.org/license.html">this</A>.
375
376<BLOCKQUOTE STYLE="padding-bottom: 0em">
377Copyright © 1994–2013 Lua.org, PUC-Rio.
378
379<P>
380Permission is hereby granted, free of charge, to any person obtaining a copy
381of this software and associated documentation files (the "Software"), to deal
382in the Software without restriction, including without limitation the rights
383to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
384copies of the Software, and to permit persons to whom the Software is
385furnished to do so, subject to the following conditions:
386
387<P>
388The above copyright notice and this permission notice shall be included in
389all copies or substantial portions of the Software.
390
391<P>
392THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
393IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
394FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
395AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
396LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
397OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
398THE SOFTWARE.
399</BLOCKQUOTE>
400<P>
401
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404Last update:
405Fri Feb 22 09:24:20 BRT 2013
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