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| author | Jerry James <james@xemacs.org> |
|---|---|
| date | Thu, 27 Mar 2014 08:59:03 -0600 |
| parents | 62b9ef1ed4ac |
| children |
| rev | line source |
|---|---|
| 428 | 1 @c -*-texinfo-*- |
| 2 @c This is part of the XEmacs Lisp Reference Manual. | |
| 444 | 3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. |
| 428 | 4 @c See the file lispref.texi for copying conditions. |
| 5 @setfilename ../../info/intro.info | |
| 6 | |
| 7 @node Copying, Introduction, Top, Top | |
| 8 @unnumbered GNU GENERAL PUBLIC LICENSE | |
| 9 @center Version 2, June 1991 | |
| 10 | |
| 11 @display | |
| 12 Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc. | |
| 13 675 Mass Ave, Cambridge, MA 02139, USA | |
| 14 | |
| 15 Everyone is permitted to copy and distribute verbatim copies | |
| 16 of this license document, but changing it is not allowed. | |
| 17 @end display | |
| 18 | |
| 19 @unnumberedsec Preamble | |
| 20 | |
| 21 The licenses for most software are designed to take away your | |
| 22 freedom to share and change it. By contrast, the GNU General Public | |
| 23 License is intended to guarantee your freedom to share and change free | |
| 24 software---to make sure the software is free for all its users. This | |
| 25 General Public License applies to most of the Free Software | |
| 26 Foundation's software and to any other program whose authors commit to | |
| 27 using it. (Some other Free Software Foundation software is covered by | |
| 28 the GNU Library General Public License instead.) You can apply it to | |
| 29 your programs, too. | |
| 30 | |
| 31 When we speak of free software, we are referring to freedom, not | |
| 32 price. Our General Public Licenses are designed to make sure that you | |
| 33 have the freedom to distribute copies of free software (and charge for | |
| 34 this service if you wish), that you receive source code or can get it | |
| 35 if you want it, that you can change the software or use pieces of it | |
| 36 in new free programs; and that you know you can do these things. | |
| 37 | |
| 38 To protect your rights, we need to make restrictions that forbid | |
| 39 anyone to deny you these rights or to ask you to surrender the rights. | |
| 40 These restrictions translate to certain responsibilities for you if you | |
| 41 distribute copies of the software, or if you modify it. | |
| 42 | |
| 43 For example, if you distribute copies of such a program, whether | |
| 44 gratis or for a fee, you must give the recipients all the rights that | |
| 45 you have. You must make sure that they, too, receive or can get the | |
| 46 source code. And you must show them these terms so they know their | |
| 47 rights. | |
| 48 | |
| 49 We protect your rights with two steps: (1) copyright the software, and | |
| 50 (2) offer you this license which gives you legal permission to copy, | |
| 51 distribute and/or modify the software. | |
| 52 | |
| 53 Also, for each author's protection and ours, we want to make certain | |
| 54 that everyone understands that there is no warranty for this free | |
| 55 software. If the software is modified by someone else and passed on, we | |
| 56 want its recipients to know that what they have is not the original, so | |
| 57 that any problems introduced by others will not reflect on the original | |
| 58 authors' reputations. | |
| 59 | |
| 60 Finally, any free program is threatened constantly by software | |
| 61 patents. We wish to avoid the danger that redistributors of a free | |
| 62 program will individually obtain patent licenses, in effect making the | |
| 63 program proprietary. To prevent this, we have made it clear that any | |
| 64 patent must be licensed for everyone's free use or not licensed at all. | |
| 65 | |
| 66 The precise terms and conditions for copying, distribution and | |
| 67 modification follow. | |
| 68 | |
| 69 @iftex | |
| 70 @unnumberedsec TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | |
| 71 @end iftex | |
| 72 @ifinfo | |
| 73 @center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | |
| 74 @end ifinfo | |
| 75 | |
| 76 @enumerate 0 | |
| 77 @item | |
| 78 This License applies to any program or other work which contains | |
| 79 a notice placed by the copyright holder saying it may be distributed | |
| 80 under the terms of this General Public License. The ``Program'', below, | |
| 81 refers to any such program or work, and a ``work based on the Program'' | |
| 82 means either the Program or any derivative work under copyright law: | |
| 83 that is to say, a work containing the Program or a portion of it, | |
| 84 either verbatim or with modifications and/or translated into another | |
| 85 language. (Hereinafter, translation is included without limitation in | |
| 86 the term ``modification''.) Each licensee is addressed as ``you''. | |
| 87 | |
| 88 Activities other than copying, distribution and modification are not | |
| 89 covered by this License; they are outside its scope. The act of | |
| 90 running the Program is not restricted, and the output from the Program | |
| 91 is covered only if its contents constitute a work based on the | |
| 92 Program (independent of having been made by running the Program). | |
| 93 Whether that is true depends on what the Program does. | |
| 94 | |
| 95 @item | |
| 96 You may copy and distribute verbatim copies of the Program's | |
| 97 source code as you receive it, in any medium, provided that you | |
| 98 conspicuously and appropriately publish on each copy an appropriate | |
| 99 copyright notice and disclaimer of warranty; keep intact all the | |
| 100 notices that refer to this License and to the absence of any warranty; | |
| 101 and give any other recipients of the Program a copy of this License | |
| 102 along with the Program. | |
| 103 | |
| 104 You may charge a fee for the physical act of transferring a copy, and | |
| 105 you may at your option offer warranty protection in exchange for a fee. | |
| 106 | |
| 107 @item | |
| 108 You may modify your copy or copies of the Program or any portion | |
| 109 of it, thus forming a work based on the Program, and copy and | |
| 110 distribute such modifications or work under the terms of Section 1 | |
| 111 above, provided that you also meet all of these conditions: | |
| 112 | |
| 113 @enumerate a | |
| 114 @item | |
| 115 You must cause the modified files to carry prominent notices | |
| 116 stating that you changed the files and the date of any change. | |
| 117 | |
| 118 @item | |
| 119 You must cause any work that you distribute or publish, that in | |
| 120 whole or in part contains or is derived from the Program or any | |
| 121 part thereof, to be licensed as a whole at no charge to all third | |
| 122 parties under the terms of this License. | |
| 123 | |
| 124 @item | |
| 125 If the modified program normally reads commands interactively | |
| 126 when run, you must cause it, when started running for such | |
| 127 interactive use in the most ordinary way, to print or display an | |
| 128 announcement including an appropriate copyright notice and a | |
| 129 notice that there is no warranty (or else, saying that you provide | |
| 130 a warranty) and that users may redistribute the program under | |
| 131 these conditions, and telling the user how to view a copy of this | |
| 132 License. (Exception: if the Program itself is interactive but | |
| 133 does not normally print such an announcement, your work based on | |
| 134 the Program is not required to print an announcement.) | |
| 135 @end enumerate | |
| 136 | |
| 137 These requirements apply to the modified work as a whole. If | |
| 138 identifiable sections of that work are not derived from the Program, | |
| 139 and can be reasonably considered independent and separate works in | |
| 140 themselves, then this License, and its terms, do not apply to those | |
| 141 sections when you distribute them as separate works. But when you | |
| 142 distribute the same sections as part of a whole which is a work based | |
| 143 on the Program, the distribution of the whole must be on the terms of | |
| 144 this License, whose permissions for other licensees extend to the | |
| 145 entire whole, and thus to each and every part regardless of who wrote it. | |
| 146 | |
| 147 Thus, it is not the intent of this section to claim rights or contest | |
| 148 your rights to work written entirely by you; rather, the intent is to | |
| 149 exercise the right to control the distribution of derivative or | |
| 150 collective works based on the Program. | |
| 151 | |
| 152 In addition, mere aggregation of another work not based on the Program | |
| 153 with the Program (or with a work based on the Program) on a volume of | |
| 154 a storage or distribution medium does not bring the other work under | |
| 155 the scope of this License. | |
| 156 | |
| 157 @item | |
| 158 You may copy and distribute the Program (or a work based on it, | |
| 159 under Section 2) in object code or executable form under the terms of | |
| 160 Sections 1 and 2 above provided that you also do one of the following: | |
| 161 | |
| 162 @enumerate a | |
| 163 @item | |
| 164 Accompany it with the complete corresponding machine-readable | |
| 165 source code, which must be distributed under the terms of Sections | |
| 166 1 and 2 above on a medium customarily used for software interchange; or, | |
| 167 | |
| 168 @item | |
| 169 Accompany it with a written offer, valid for at least three | |
| 170 years, to give any third party, for a charge no more than your | |
| 171 cost of physically performing source distribution, a complete | |
| 172 machine-readable copy of the corresponding source code, to be | |
| 173 distributed under the terms of Sections 1 and 2 above on a medium | |
| 174 customarily used for software interchange; or, | |
| 175 | |
| 176 @item | |
| 177 Accompany it with the information you received as to the offer | |
| 178 to distribute corresponding source code. (This alternative is | |
| 179 allowed only for noncommercial distribution and only if you | |
| 180 received the program in object code or executable form with such | |
| 181 an offer, in accord with Subsection b above.) | |
| 182 @end enumerate | |
| 183 | |
| 184 The source code for a work means the preferred form of the work for | |
| 185 making modifications to it. For an executable work, complete source | |
| 186 code means all the source code for all modules it contains, plus any | |
| 187 associated interface definition files, plus the scripts used to | |
| 188 control compilation and installation of the executable. However, as a | |
| 189 special exception, the source code distributed need not include | |
| 190 anything that is normally distributed (in either source or binary | |
| 191 form) with the major components (compiler, kernel, and so on) of the | |
| 192 operating system on which the executable runs, unless that component | |
| 193 itself accompanies the executable. | |
| 194 | |
| 195 If distribution of executable or object code is made by offering | |
| 196 access to copy from a designated place, then offering equivalent | |
| 197 access to copy the source code from the same place counts as | |
| 198 distribution of the source code, even though third parties are not | |
| 199 compelled to copy the source along with the object code. | |
| 200 | |
| 201 @item | |
| 202 You may not copy, modify, sublicense, or distribute the Program | |
| 203 except as expressly provided under this License. Any attempt | |
| 204 otherwise to copy, modify, sublicense or distribute the Program is | |
| 205 void, and will automatically terminate your rights under this License. | |
| 206 However, parties who have received copies, or rights, from you under | |
| 207 this License will not have their licenses terminated so long as such | |
| 208 parties remain in full compliance. | |
| 209 | |
| 210 @item | |
| 211 You are not required to accept this License, since you have not | |
| 212 signed it. However, nothing else grants you permission to modify or | |
| 213 distribute the Program or its derivative works. These actions are | |
| 214 prohibited by law if you do not accept this License. Therefore, by | |
| 215 modifying or distributing the Program (or any work based on the | |
| 216 Program), you indicate your acceptance of this License to do so, and | |
| 217 all its terms and conditions for copying, distributing or modifying | |
| 218 the Program or works based on it. | |
| 219 | |
| 220 @item | |
| 221 Each time you redistribute the Program (or any work based on the | |
| 222 Program), the recipient automatically receives a license from the | |
| 223 original licensor to copy, distribute or modify the Program subject to | |
| 224 these terms and conditions. You may not impose any further | |
| 225 restrictions on the recipients' exercise of the rights granted herein. | |
| 226 You are not responsible for enforcing compliance by third parties to | |
| 227 this License. | |
| 228 | |
| 229 @item | |
| 230 If, as a consequence of a court judgment or allegation of patent | |
| 231 infringement or for any other reason (not limited to patent issues), | |
| 232 conditions are imposed on you (whether by court order, agreement or | |
| 233 otherwise) that contradict the conditions of this License, they do not | |
| 234 excuse you from the conditions of this License. If you cannot | |
| 235 distribute so as to satisfy simultaneously your obligations under this | |
| 236 License and any other pertinent obligations, then as a consequence you | |
| 237 may not distribute the Program at all. For example, if a patent | |
| 238 license would not permit royalty-free redistribution of the Program by | |
| 239 all those who receive copies directly or indirectly through you, then | |
| 240 the only way you could satisfy both it and this License would be to | |
| 241 refrain entirely from distribution of the Program. | |
| 242 | |
| 243 If any portion of this section is held invalid or unenforceable under | |
| 244 any particular circumstance, the balance of the section is intended to | |
| 245 apply and the section as a whole is intended to apply in other | |
| 246 circumstances. | |
| 247 | |
| 248 It is not the purpose of this section to induce you to infringe any | |
| 249 patents or other property right claims or to contest validity of any | |
| 250 such claims; this section has the sole purpose of protecting the | |
| 251 integrity of the free software distribution system, which is | |
| 252 implemented by public license practices. Many people have made | |
| 253 generous contributions to the wide range of software distributed | |
| 254 through that system in reliance on consistent application of that | |
| 255 system; it is up to the author/donor to decide if he or she is willing | |
| 256 to distribute software through any other system and a licensee cannot | |
| 257 impose that choice. | |
| 258 | |
| 259 This section is intended to make thoroughly clear what is believed to | |
| 260 be a consequence of the rest of this License. | |
| 261 | |
| 262 @item | |
| 263 If the distribution and/or use of the Program is restricted in | |
| 264 certain countries either by patents or by copyrighted interfaces, the | |
| 265 original copyright holder who places the Program under this License | |
| 266 may add an explicit geographical distribution limitation excluding | |
| 267 those countries, so that distribution is permitted only in or among | |
| 268 countries not thus excluded. In such case, this License incorporates | |
| 269 the limitation as if written in the body of this License. | |
| 270 | |
| 271 @item | |
| 272 The Free Software Foundation may publish revised and/or new versions | |
| 273 of the General Public License from time to time. Such new versions will | |
| 274 be similar in spirit to the present version, but may differ in detail to | |
| 275 address new problems or concerns. | |
| 276 | |
| 277 Each version is given a distinguishing version number. If the Program | |
| 278 specifies a version number of this License which applies to it and ``any | |
| 279 later version'', you have the option of following the terms and conditions | |
| 280 either of that version or of any later version published by the Free | |
| 281 Software Foundation. If the Program does not specify a version number of | |
| 282 this License, you may choose any version ever published by the Free Software | |
| 283 Foundation. | |
| 284 | |
| 285 @item | |
| 286 If you wish to incorporate parts of the Program into other free | |
| 287 programs whose distribution conditions are different, write to the author | |
| 288 to ask for permission. For software which is copyrighted by the Free | |
| 289 Software Foundation, write to the Free Software Foundation; we sometimes | |
| 290 make exceptions for this. Our decision will be guided by the two goals | |
| 291 of preserving the free status of all derivatives of our free software and | |
| 292 of promoting the sharing and reuse of software generally. | |
| 293 | |
| 294 @iftex | |
| 295 @heading NO WARRANTY | |
| 296 @end iftex | |
| 297 @ifinfo | |
| 298 @center NO WARRANTY | |
| 299 @end ifinfo | |
| 300 | |
| 301 @item | |
| 302 BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY | |
| 303 FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW@. EXCEPT WHEN | |
| 304 OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES | |
| 305 PROVIDE THE PROGRAM ``AS IS'' WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED | |
| 306 OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF | |
| 307 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE@. THE ENTIRE RISK AS | |
| 308 TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU@. SHOULD THE | |
| 309 PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, | |
| 310 REPAIR OR CORRECTION. | |
| 311 | |
| 312 @item | |
| 313 IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING | |
| 314 WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR | |
| 315 REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, | |
| 316 INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING | |
| 317 OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED | |
| 318 TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY | |
| 319 YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER | |
| 320 PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE | |
| 321 POSSIBILITY OF SUCH DAMAGES. | |
| 322 @end enumerate | |
| 323 | |
| 324 @iftex | |
| 325 @heading END OF TERMS AND CONDITIONS | |
| 326 @end iftex | |
| 327 @ifinfo | |
| 328 @center END OF TERMS AND CONDITIONS | |
| 329 @end ifinfo | |
| 330 | |
| 331 @page | |
| 332 @unnumberedsec How to Apply These Terms to Your New Programs | |
| 333 | |
| 334 If you develop a new program, and you want it to be of the greatest | |
| 335 possible use to the public, the best way to achieve this is to make it | |
| 336 free software which everyone can redistribute and change under these terms. | |
| 337 | |
| 338 To do so, attach the following notices to the program. It is safest | |
| 339 to attach them to the start of each source file to most effectively | |
| 340 convey the exclusion of warranty; and each file should have at least | |
| 341 the ``copyright'' line and a pointer to where the full notice is found. | |
| 342 | |
| 343 @smallexample | |
| 344 @var{one line to give the program's name and an idea of what it does.} | |
| 345 Copyright (C) 19@var{yy} @var{name of author} | |
| 346 | |
| 347 This program is free software; you can redistribute it and/or | |
| 348 modify it under the terms of the GNU General Public License | |
| 349 as published by the Free Software Foundation; either version 2 | |
| 350 of the License, or (at your option) any later version. | |
| 351 | |
| 352 This program is distributed in the hope that it will be useful, | |
| 353 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 354 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE@. See the | |
| 355 GNU General Public License for more details. | |
| 356 | |
| 357 You should have received a copy of the GNU General Public License | |
| 358 along with this program; if not, write to the Free Software | |
| 359 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
| 360 @end smallexample | |
| 361 | |
| 362 Also add information on how to contact you by electronic and paper mail. | |
| 363 | |
| 364 If the program is interactive, make it output a short notice like this | |
| 365 when it starts in an interactive mode: | |
| 366 | |
| 367 @smallexample | |
| 368 Gnomovision version 69, Copyright (C) 19@var{yy} @var{name of author} | |
| 369 Gnomovision comes with ABSOLUTELY NO WARRANTY; for details | |
| 370 type `show w'. This is free software, and you are welcome | |
| 444 | 371 to redistribute it under certain conditions; type `show c' |
| 428 | 372 for details. |
| 373 @end smallexample | |
| 374 | |
| 375 The hypothetical commands @samp{show w} and @samp{show c} should show | |
| 376 the appropriate parts of the General Public License. Of course, the | |
| 377 commands you use may be called something other than @samp{show w} and | |
| 378 @samp{show c}; they could even be mouse-clicks or menu items---whatever | |
| 379 suits your program. | |
| 380 | |
| 381 You should also get your employer (if you work as a programmer) or your | |
| 382 school, if any, to sign a ``copyright disclaimer'' for the program, if | |
| 383 necessary. Here is a sample; alter the names: | |
| 384 | |
| 385 @smallexample | |
| 386 @group | |
| 387 Yoyodyne, Inc., hereby disclaims all copyright | |
| 388 interest in the program `Gnomovision' | |
| 444 | 389 (which makes passes at compilers) written |
| 428 | 390 by James Hacker. |
| 391 | |
| 392 @var{signature of Ty Coon}, 1 April 1989 | |
| 393 Ty Coon, President of Vice | |
| 394 @end group | |
| 395 @end smallexample | |
| 396 | |
| 397 This General Public License does not permit incorporating your program into | |
| 398 proprietary programs. If your program is a subroutine library, you may | |
| 399 consider it more useful to permit linking proprietary applications with the | |
| 400 library. If this is what you want to do, use the GNU Library General | |
| 401 Public License instead of this License. | |
| 402 | |
| 693 | 403 @node Introduction, Packaging, Copying, Top |
| 428 | 404 @chapter Introduction |
| 405 | |
| 406 Most of the XEmacs text editor is written in the programming | |
| 407 language called XEmacs Lisp. You can write new code in XEmacs Lisp and | |
| 408 install it as an extension to the editor. However, XEmacs Lisp is more | |
| 409 than a mere ``extension language''; it is a full computer programming | |
| 410 language in its own right. You can use it as you would any other | |
| 411 programming language. | |
| 412 | |
| 413 Because XEmacs Lisp is designed for use in an editor, it has special | |
| 414 features for scanning and parsing text as well as features for handling | |
| 415 files, buffers, displays, subprocesses, and so on. XEmacs Lisp is | |
| 416 closely integrated with the editing facilities; thus, editing commands | |
| 417 are functions that can also conveniently be called from Lisp programs, | |
| 418 and parameters for customization are ordinary Lisp variables. | |
| 419 | |
| 420 This manual describes XEmacs Lisp, presuming considerable familiarity | |
| 421 with the use of XEmacs for editing. (See @cite{The XEmacs Reference | |
| 422 Manual}, for this basic information.) Generally speaking, the earlier | |
| 423 chapters describe features of XEmacs Lisp that have counterparts in many | |
| 424 programming languages, and later chapters describe features that are | |
| 425 peculiar to XEmacs Lisp or relate specifically to editing. | |
| 426 | |
| 427 This is edition 3.3. | |
| 428 | |
| 429 @menu | |
| 430 * Caveats:: Flaws and a request for help. | |
| 431 * Lisp History:: XEmacs Lisp is descended from Maclisp. | |
| 432 * Conventions:: How the manual is formatted. | |
| 433 * Acknowledgements:: The authors, editors, and sponsors of this manual. | |
| 434 @end menu | |
| 435 | |
|
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436 @node Caveats, Lisp History, Introduction, Introduction |
| 428 | 437 @section Caveats |
| 438 | |
| 439 This manual has gone through numerous drafts. It is nearly complete | |
| 440 but not flawless. There are a few topics that are not covered, either | |
| 441 because we consider them secondary (such as most of the individual | |
| 442 modes) or because they are yet to be written. Because we are not able | |
| 443 to deal with them completely, we have left out several parts | |
| 444 | 444 intentionally. |
| 428 | 445 |
| 446 The manual should be fully correct in what it does cover, and it is | |
| 447 therefore open to criticism on anything it says---from specific examples | |
| 448 and descriptive text, to the ordering of chapters and sections. If | |
| 449 something is confusing, or you find that you have to look at the sources | |
| 450 or experiment to learn something not covered in the manual, then perhaps | |
| 451 the manual should be fixed. Please let us know. | |
| 452 | |
| 453 @iftex | |
| 454 As you use the manual, we ask that you mark pages with corrections so | |
| 455 you can later look them up and send them in. If you think of a simple, | |
| 456 real-life example for a function or group of functions, please make an | |
| 457 effort to write it up and send it in. Please reference any comments to | |
| 458 the chapter name, section name, and function name, as appropriate, since | |
| 459 page numbers and chapter and section numbers will change and we may have | |
| 460 trouble finding the text you are talking about. Also state the number | |
| 461 of the edition you are criticizing. | |
| 462 @end iftex | |
| 463 @ifinfo | |
| 464 | |
| 465 As you use this manual, we ask that you send corrections as soon as you | |
| 466 find them. If you think of a simple, real life example for a function | |
| 467 or group of functions, please make an effort to write it up and send it | |
| 468 in. Please reference any comments to the node name and function or | |
| 469 variable name, as appropriate. Also state the number of the edition | |
| 470 which you are criticizing. | |
| 471 @end ifinfo | |
| 472 | |
| 473 This manual was originally written for FSF Emacs 19 and was updated by | |
| 474 Ben Wing (ben@@xemacs.org) for Lucid Emacs 19.10 and later for XEmacs | |
| 475 19.12, 19.13, 19.14, and 20.0. It was further updated by the XEmacs | |
| 476 Development Team for 19.15 and 20.1. Please send comments and | |
| 477 corrections relating to XEmacs-specific portions of this manual to | |
| 478 @example | |
| 479 xemacs@@xemacs.org | |
| 480 @end example | |
| 481 | |
| 482 or post to the newsgroup | |
| 483 @example | |
| 484 comp.emacs.xemacs | |
| 485 @end example | |
| 486 | |
| 487 @noindent | |
| 488 @display | |
| 489 --Ben Wing | |
| 490 @end display | |
| 491 | |
|
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492 @node Lisp History, Conventions, Caveats, Introduction |
| 428 | 493 @section Lisp History |
| 494 @cindex Lisp history | |
| 495 | |
| 496 Lisp (LISt Processing language) was first developed in the late 1950's | |
| 497 at the Massachusetts Institute of Technology for research in artificial | |
| 498 intelligence. The great power of the Lisp language makes it superior | |
| 499 for other purposes as well, such as writing editing commands. | |
| 500 | |
| 501 @cindex Maclisp | |
| 502 @cindex Common Lisp | |
| 503 Dozens of Lisp implementations have been built over the years, each | |
| 504 with its own idiosyncrasies. Many of them were inspired by Maclisp, | |
| 505 which was written in the 1960's at MIT's Project MAC. Eventually the | |
| 506 implementors of the descendants of Maclisp came together and developed a | |
| 507 standard for Lisp systems, called Common Lisp. | |
| 508 | |
| 509 XEmacs Lisp is largely inspired by Maclisp, and a little by Common | |
| 510 Lisp. If you know Common Lisp, you will notice many similarities. | |
| 511 However, many of the features of Common Lisp have been omitted or | |
| 512 simplified in order to reduce the memory requirements of XEmacs. | |
| 513 Sometimes the simplifications are so drastic that a Common Lisp user | |
| 514 might be very confused. We will occasionally point out how XEmacs | |
| 515 Lisp differs from Common Lisp. If you don't know Common Lisp, don't | |
| 516 worry about it; this manual is self-contained. | |
| 517 | |
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518 @node Conventions, Acknowledgements, Lisp History, Introduction |
| 428 | 519 @section Conventions |
| 520 | |
| 521 This section explains the notational conventions that are used in this | |
| 522 manual. You may want to skip this section and refer back to it later. | |
| 523 | |
| 524 @menu | |
| 525 * Some Terms:: Explanation of terms we use in this manual. | |
| 526 * nil and t:: How the symbols @code{nil} and @code{t} are used. | |
| 527 * Evaluation Notation:: The format we use for examples of evaluation. | |
| 528 * Printing Notation:: The format we use for examples that print output. | |
| 529 * Error Messages:: The format we use for examples of errors. | |
| 530 * Buffer Text Notation:: The format we use for buffer contents in examples. | |
| 531 * Format of Descriptions:: Notation for describing functions, variables, etc. | |
| 532 @end menu | |
| 533 | |
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534 @node Some Terms, nil and t, Conventions, Conventions |
| 428 | 535 @subsection Some Terms |
| 536 | |
| 537 Throughout this manual, the phrases ``the Lisp reader'' and ``the Lisp | |
| 538 printer'' are used to refer to those routines in Lisp that convert | |
| 539 textual representations of Lisp objects into actual Lisp objects, and vice | |
| 540 versa. @xref{Printed Representation}, for more details. You, the | |
| 541 person reading this manual, are thought of as ``the programmer'' and are | |
| 542 addressed as ``you''. ``The user'' is the person who uses Lisp programs, | |
| 543 including those you write. | |
| 544 | |
| 545 @cindex fonts | |
| 546 Examples of Lisp code appear in this font or form: @code{(list 1 2 | |
| 547 3)}. Names that represent arguments or metasyntactic variables appear | |
| 548 in this font or form: @var{first-number}. | |
| 549 | |
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550 @node nil and t, Evaluation Notation, Some Terms, Conventions |
| 428 | 551 @subsection @code{nil} and @code{t} |
| 552 @cindex @code{nil}, uses of | |
| 553 @cindex truth value | |
| 554 @cindex boolean | |
| 555 @cindex false | |
| 556 | |
| 557 In Lisp, the symbol @code{nil} has three separate meanings: it | |
| 558 is a symbol with the name @samp{nil}; it is the logical truth value | |
| 559 @var{false}; and it is the empty list---the list of zero elements. | |
| 560 When used as a variable, @code{nil} always has the value @code{nil}. | |
| 561 | |
| 562 As far as the Lisp reader is concerned, @samp{()} and @samp{nil} are | |
| 563 identical: they stand for the same object, the symbol @code{nil}. The | |
| 564 different ways of writing the symbol are intended entirely for human | |
| 565 readers. After the Lisp reader has read either @samp{()} or @samp{nil}, | |
| 566 there is no way to determine which representation was actually written | |
| 567 by the programmer. | |
| 568 | |
| 569 In this manual, we use @code{()} when we wish to emphasize that it | |
| 570 means the empty list, and we use @code{nil} when we wish to emphasize | |
| 571 that it means the truth value @var{false}. That is a good convention to use | |
| 572 in Lisp programs also. | |
| 573 | |
| 574 @example | |
| 575 (cons 'foo ()) ; @r{Emphasize the empty list} | |
| 576 (not nil) ; @r{Emphasize the truth value @var{false}} | |
| 577 @end example | |
| 578 | |
| 579 @cindex @code{t} and truth | |
| 580 @cindex true | |
| 581 In contexts where a truth value is expected, any non-@code{nil} value | |
| 582 is considered to be @var{true}. However, @code{t} is the preferred way | |
| 583 to represent the truth value @var{true}. When you need to choose a | |
| 584 value which represents @var{true}, and there is no other basis for | |
| 585 choosing, use @code{t}. The symbol @code{t} always has value @code{t}. | |
| 586 | |
| 587 In XEmacs Lisp, @code{nil} and @code{t} are special symbols that always | |
| 588 evaluate to themselves. This is so that you do not need to quote them | |
| 589 to use them as constants in a program. An attempt to change their | |
| 590 values results in a @code{setting-constant} error. @xref{Accessing | |
| 591 Variables}. | |
| 592 | |
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593 @node Evaluation Notation, Printing Notation, nil and t, Conventions |
| 428 | 594 @subsection Evaluation Notation |
| 595 @cindex evaluation notation | |
| 596 @cindex documentation notation | |
| 597 | |
| 598 A Lisp expression that you can evaluate is called a @dfn{form}. | |
| 599 Evaluating a form always produces a result, which is a Lisp object. In | |
| 600 the examples in this manual, this is indicated with @samp{@result{}}: | |
| 601 | |
| 602 @example | |
| 603 (car '(1 2)) | |
| 604 @result{} 1 | |
| 605 @end example | |
| 606 | |
| 607 @noindent | |
| 608 You can read this as ``@code{(car '(1 2))} evaluates to 1''. | |
| 609 | |
| 610 When a form is a macro call, it expands into a new form for Lisp to | |
| 611 evaluate. We show the result of the expansion with | |
| 612 @samp{@expansion{}}. We may or may not show the actual result of the | |
| 613 evaluation of the expanded form. | |
| 614 | |
| 615 @example | |
| 616 (news-cadr '(a b c)) | |
| 617 @expansion{} (car (cdr '(a b c))) | |
| 618 @result{} b | |
| 619 @end example | |
| 620 | |
| 621 Sometimes to help describe one form we show another form that | |
| 622 produces identical results. The exact equivalence of two forms is | |
| 623 indicated with @samp{@equiv{}}. | |
| 624 | |
| 625 @example | |
| 626 (cons 'a nil) @equiv{} (list 'a) | |
| 627 @end example | |
| 628 | |
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629 @node Printing Notation, Error Messages, Evaluation Notation, Conventions |
| 428 | 630 @subsection Printing Notation |
| 631 @cindex printing notation | |
| 632 | |
| 633 Many of the examples in this manual print text when they are | |
| 634 evaluated. If you execute example code in a Lisp Interaction buffer | |
| 635 (such as the buffer @samp{*scratch*}), the printed text is inserted into | |
| 636 the buffer. If you execute the example by other means (such as by | |
| 637 evaluating the function @code{eval-region}), the printed text is | |
| 638 displayed in the echo area. You should be aware that text displayed in | |
| 639 the echo area is truncated to a single line. | |
| 640 | |
| 641 Examples in this manual indicate printed text with @samp{@print{}}, | |
| 642 irrespective of where that text goes. The value returned by evaluating | |
| 643 the form (here @code{bar}) follows on a separate line. | |
| 644 | |
| 645 @example | |
| 646 @group | |
| 647 (progn (print 'foo) (print 'bar)) | |
| 648 @print{} foo | |
| 649 @print{} bar | |
| 650 @result{} bar | |
| 651 @end group | |
| 652 @end example | |
| 653 | |
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654 @node Error Messages, Buffer Text Notation, Printing Notation, Conventions |
| 428 | 655 @subsection Error Messages |
| 656 @cindex error message notation | |
| 657 | |
| 658 Some examples signal errors. This normally displays an error message | |
| 659 in the echo area. We show the error message on a line starting with | |
| 660 @samp{@error{}}. Note that @samp{@error{}} itself does not appear in | |
| 661 the echo area. | |
| 662 | |
| 663 @example | |
| 664 (+ 23 'x) | |
| 665 @error{} Wrong type argument: integer-or-marker-p, x | |
| 666 @end example | |
| 667 | |
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668 @node Buffer Text Notation, Format of Descriptions, Error Messages, Conventions |
| 428 | 669 @subsection Buffer Text Notation |
| 670 @cindex buffer text notation | |
| 671 | |
| 672 Some examples show modifications to text in a buffer, with ``before'' | |
| 673 and ``after'' versions of the text. These examples show the contents of | |
| 674 the buffer in question between two lines of dashes containing the buffer | |
| 675 name. In addition, @samp{@point{}} indicates the location of point. | |
| 676 (The symbol for point, of course, is not part of the text in the buffer; | |
| 677 it indicates the place @emph{between} two characters where point is | |
| 678 located.) | |
| 679 | |
| 680 @example | |
| 681 ---------- Buffer: foo ---------- | |
| 682 This is the @point{}contents of foo. | |
| 683 ---------- Buffer: foo ---------- | |
| 684 | |
| 685 (insert "changed ") | |
| 686 @result{} nil | |
| 687 ---------- Buffer: foo ---------- | |
| 688 This is the changed @point{}contents of foo. | |
| 689 ---------- Buffer: foo ---------- | |
| 690 @end example | |
| 691 | |
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692 @node Format of Descriptions, , Buffer Text Notation, Conventions |
| 428 | 693 @subsection Format of Descriptions |
| 694 @cindex description format | |
| 695 | |
| 696 Functions, variables, macros, commands, user options, and special | |
| 697 forms are described in this manual in a uniform format. The first | |
| 698 line of a description contains the name of the item followed by its | |
| 699 arguments, if any. | |
| 700 @ifinfo | |
| 701 The category---function, variable, or whatever---appears at the | |
| 702 beginning of the line. | |
| 703 @end ifinfo | |
| 704 @iftex | |
| 705 The category---function, variable, or whatever---is printed next to the | |
| 706 right margin. | |
| 707 @end iftex | |
| 708 The description follows on succeeding lines, sometimes with examples. | |
| 709 | |
| 710 @menu | |
| 711 * A Sample Function Description:: A description of an imaginary | |
| 712 function, @code{foo}. | |
| 713 * A Sample Variable Description:: A description of an imaginary | |
| 714 variable, | |
| 444 | 715 @code{electric-future-map}. |
| 428 | 716 @end menu |
| 717 | |
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718 @node A Sample Function Description, A Sample Variable Description, Format of Descriptions, Format of Descriptions |
| 428 | 719 @subsubsection A Sample Function Description |
| 720 @cindex function descriptions | |
| 721 @cindex command descriptions | |
| 722 @cindex macro descriptions | |
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723 @cindex special operator descriptions |
| 428 | 724 |
| 725 In a function description, the name of the function being described | |
| 726 appears first. It is followed on the same line by a list of parameters. | |
| 727 The names used for the parameters are also used in the body of the | |
| 728 description. | |
| 729 | |
| 730 The appearance of the keyword @code{&optional} in the parameter list | |
| 731 indicates that the arguments for subsequent parameters may be omitted | |
| 732 (omitted parameters default to @code{nil}). Do not write | |
| 733 @code{&optional} when you call the function. | |
| 734 | |
| 735 The keyword @code{&rest} (which will always be followed by a single | |
| 736 parameter) indicates that any number of arguments can follow. The value | |
| 737 of the single following parameter will be a list of all these arguments. | |
| 738 Do not write @code{&rest} when you call the function. | |
| 739 | |
| 740 Here is a description of an imaginary function @code{foo}: | |
| 741 | |
| 742 @defun foo integer1 &optional integer2 &rest integers | |
| 743 The function @code{foo} subtracts @var{integer1} from @var{integer2}, | |
| 744 then adds all the rest of the arguments to the result. If @var{integer2} | |
| 745 is not supplied, then the number 19 is used by default. | |
| 746 | |
| 747 @example | |
| 748 (foo 1 5 3 9) | |
| 749 @result{} 16 | |
| 750 (foo 5) | |
| 751 @result{} 14 | |
| 752 @end example | |
| 753 | |
| 754 More generally, | |
| 755 | |
| 756 @example | |
| 757 (foo @var{w} @var{x} @var{y}@dots{}) | |
| 758 @equiv{} | |
| 759 (+ (- @var{x} @var{w}) @var{y}@dots{}) | |
| 760 @end example | |
| 761 @end defun | |
| 762 | |
| 763 Any parameter whose name contains the name of a type (e.g., | |
| 764 @var{integer}, @var{integer1} or @var{buffer}) is expected to be of that | |
| 765 type. A plural of a type (such as @var{buffers}) often means a list of | |
| 766 objects of that type. Parameters named @var{object} may be of any type. | |
| 767 (@xref{Lisp Data Types}, for a list of XEmacs object types.) | |
| 768 Parameters with other sorts of names (e.g., @var{new-file}) are | |
| 769 discussed specifically in the description of the function. In some | |
| 770 sections, features common to parameters of several functions are | |
| 771 described at the beginning. | |
| 772 | |
| 773 @xref{Lambda Expressions}, for a more complete description of optional | |
| 774 and rest arguments. | |
| 775 | |
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776 Command, macro, and special operator descriptions have the same format, |
| 428 | 777 but the word `Function' is replaced by `Command', `Macro', or `Special |
| 778 Form', respectively. Commands are simply functions that may be called | |
| 779 interactively; macros process their arguments differently from functions | |
| 780 (the arguments are not evaluated), but are presented the same way. | |
| 781 | |
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782 Special operator descriptions use a more complex notation to specify |
| 428 | 783 optional and repeated parameters because they can break the argument |
| 784 list down into separate arguments in more complicated ways. | |
| 785 @samp{@code{@r{[}@var{optional-arg}@r{]}}} means that @var{optional-arg} is | |
| 786 optional and @samp{@var{repeated-args}@dots{}} stands for zero or more | |
| 787 arguments. Parentheses are used when several arguments are grouped into | |
| 788 additional levels of list structure. Here is an example: | |
| 789 | |
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790 @deffn {Special Operator} count-loop (@var{var} [@var{from} @var{to} [@var{inc}]]) @var{body}@dots{} |
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791 This imaginary special operator implements a loop that executes the |
| 428 | 792 @var{body} forms and then increments the variable @var{var} on each |
| 793 iteration. On the first iteration, the variable has the value | |
| 794 @var{from}; on subsequent iterations, it is incremented by 1 (or by | |
| 795 @var{inc} if that is given). The loop exits before executing @var{body} | |
| 796 if @var{var} equals @var{to}. Here is an example: | |
| 797 | |
| 798 @example | |
| 799 (count-loop (i 0 10) | |
| 800 (prin1 i) (princ " ") | |
| 801 (prin1 (aref vector i)) (terpri)) | |
| 802 @end example | |
| 803 | |
| 804 If @var{from} and @var{to} are omitted, then @var{var} is bound to | |
| 805 @code{nil} before the loop begins, and the loop exits if @var{var} is | |
| 806 non-@code{nil} at the beginning of an iteration. Here is an example: | |
| 807 | |
| 808 @example | |
| 809 (count-loop (done) | |
| 810 (if (pending) | |
| 811 (fixit) | |
| 812 (setq done t))) | |
| 813 @end example | |
| 814 | |
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815 With this special operator, the arguments @var{from} and @var{to} are |
| 428 | 816 optional, but must both be present or both absent. If they are present, |
| 817 @var{inc} may optionally be specified as well. These arguments are | |
| 818 grouped with the argument @var{var} into a list, to distinguish them | |
| 819 from @var{body}, which includes all remaining elements of the form. | |
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820 @end deffn |
| 428 | 821 |
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822 @node A Sample Variable Description, , A Sample Function Description, Format of Descriptions |
| 428 | 823 @subsubsection A Sample Variable Description |
| 824 @cindex variable descriptions | |
| 825 @cindex option descriptions | |
| 826 | |
| 827 A @dfn{variable} is a name that can hold a value. Although any | |
| 828 variable can be set by the user, certain variables that exist | |
| 829 specifically so that users can change them are called @dfn{user | |
| 830 options}. Ordinary variables and user options are described using a | |
| 831 format like that for functions except that there are no arguments. | |
| 832 | |
| 833 Here is a description of the imaginary @code{electric-future-map} | |
| 834 variable.@refill | |
| 835 | |
| 836 @defvar electric-future-map | |
| 837 The value of this variable is a full keymap used by Electric Command | |
| 838 Future mode. The functions in this map allow you to edit commands you | |
| 839 have not yet thought about executing. | |
| 840 @end defvar | |
| 841 | |
| 842 User option descriptions have the same format, but `Variable' is | |
| 843 replaced by `User Option'. | |
| 844 | |
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845 @node Acknowledgements, , Conventions, Introduction |
| 428 | 846 @section Acknowledgements |
| 847 | |
| 848 This manual was based on the GNU Emacs Lisp Reference Manual, version | |
| 849 2.4, written by Robert Krawitz, Bil Lewis, Dan LaLiberte, Richard | |
| 850 M. Stallman and Chris Welty, the volunteers of the GNU manual group, in | |
| 851 an effort extending over several years. Robert J. Chassell helped to | |
| 852 review and edit the manual, with the support of the Defense Advanced | |
| 853 Research Projects Agency, ARPA Order 6082, arranged by Warren A. Hunt, | |
| 854 Jr. of Computational Logic, Inc. | |
| 855 | |
| 856 Ben Wing adapted this manual for XEmacs 19.14 and 20.0, and earlier | |
| 857 for Lucid Emacs 19.10, XEmacs 19.12, and XEmacs 19.13. He is the sole | |
| 858 author of many of the manual sections, in particular the XEmacs-specific | |
| 859 sections: events, faces, extents, glyphs, specifiers, toolbar, menubars, | |
| 860 scrollbars, dialog boxes, devices, consoles, hash tables, range tables, | |
| 861 char tables, databases, and others. The section on annotations was | |
| 862 originally written by Chuck Thompson. Corrections to v3.1 and later were | |
| 863 done by Martin Buchholz, Steve Baur, and Hrvoje Niksic. | |
| 864 | |
| 865 Corrections to the original GNU Emacs Lisp Reference Manual were | |
| 866 supplied by Karl Berry, Jim Blandy, Bard Bloom, Stephane Boucher, David | |
| 867 Boyes, Alan Carroll, Richard Davis, Lawrence R. Dodd, Peter Doornbosch, | |
| 868 David A. Duff, Chris Eich, Beverly Erlebacher, David Eckelkamp, Ralf | |
| 869 Fassel, Eirik Fuller, Stephen Gildea, Bob Glickstein, Eric Hanchrow, | |
| 870 George Hartzell, Nathan Hess, Masayuki Ida, Dan Jacobson, Jak Kirman, | |
| 871 Bob Knighten, Frederick M. Korz, Joe Lammens, Glenn M. Lewis, K. Richard | |
| 872 Magill, Brian Marick, Roland McGrath, Skip Montanaro, John Gardiner | |
| 873 Myers, Thomas A. Peterson, Francesco Potorti, Friedrich Pukelsheim, | |
| 874 Arnold D. Robbins, Raul Rockwell, Per Starback, Shinichirou Sugou, Kimmo | |
| 875 Suominen, Edward Tharp, Bill Trost, Rickard Westman, Jean White, Matthew | |
| 876 Wilding, Carl Witty, Dale Worley, Rusty Wright, and David D. Zuhn. |