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diff --git a/lispref/intro.texi b/lispref/intro.texi deleted file mode 100644 index def0d1c84bc..00000000000 --- a/lispref/intro.texi +++ /dev/null @@ -1,866 +0,0 @@ -@c -*-texinfo-*- -@c This is part of the GNU Emacs Lisp Reference Manual. -@c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. -@c See the file elisp.texi for copying conditions. -@setfilename ../info/intro - -@node Copying, Introduction, Top, Top -@comment node-name, next, previous, up -@unnumbered GNU GENERAL PUBLIC LICENSE -@center Version 2, June 1991 - -@display -Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc. -675 Mass Ave, Cambridge, MA 02139, USA - -Everyone is permitted to copy and distribute verbatim copies -of this license document, but changing it is not allowed. -@end display - -@unnumberedsec Preamble - - The licenses for most software are designed to take away your -freedom to share and change it. By contrast, the GNU General Public -License is intended to guarantee your freedom to share and change free -software---to make sure the software is free for all its users. This -General Public License applies to most of the Free Software -Foundation's software and to any other program whose authors commit to -using it. (Some other Free Software Foundation software is covered by -the GNU Library General Public License instead.) You can apply it to -your programs, too. - - When we speak of free software, we are referring to freedom, not -price. Our General Public Licenses are designed to make sure that you -have the freedom to distribute copies of free software (and charge for -this service if you wish), that you receive source code or can get it -if you want it, that you can change the software or use pieces of it -in new free programs; and that you know you can do these things. - - To protect your rights, we need to make restrictions that forbid -anyone to deny you these rights or to ask you to surrender the rights. -These restrictions translate to certain responsibilities for you if you -distribute copies of the software, or if you modify it. - - For example, if you distribute copies of such a program, whether -gratis or for a fee, you must give the recipients all the rights that -you have. You must make sure that they, too, receive or can get the -source code. And you must show them these terms so they know their -rights. - - We protect your rights with two steps: (1) copyright the software, and -(2) offer you this license which gives you legal permission to copy, -distribute and/or modify the software. - - Also, for each author's protection and ours, we want to make certain -that everyone understands that there is no warranty for this free -software. If the software is modified by someone else and passed on, we -want its recipients to know that what they have is not the original, so -that any problems introduced by others will not reflect on the original -authors' reputations. - - Finally, any free program is threatened constantly by software -patents. We wish to avoid the danger that redistributors of a free -program will individually obtain patent licenses, in effect making the -program proprietary. To prevent this, we have made it clear that any -patent must be licensed for everyone's free use or not licensed at all. - - The precise terms and conditions for copying, distribution and -modification follow. - -@iftex -@unnumberedsec TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION -@end iftex -@ifinfo -@center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION -@end ifinfo - -@enumerate 0 -@item -This License applies to any program or other work which contains -a notice placed by the copyright holder saying it may be distributed -under the terms of this General Public License. The ``Program'', below, -refers to any such program or work, and a ``work based on the Program'' -means either the Program or any derivative work under copyright law: -that is to say, a work containing the Program or a portion of it, -either verbatim or with modifications and/or translated into another -language. (Hereinafter, translation is included without limitation in -the term ``modification''.) Each licensee is addressed as ``you''. - -Activities other than copying, distribution and modification are not -covered by this License; they are outside its scope. The act of -running the Program is not restricted, and the output from the Program -is covered only if its contents constitute a work based on the -Program (independent of having been made by running the Program). -Whether that is true depends on what the Program does. - -@item -You may copy and distribute verbatim copies of the Program's -source code as you receive it, in any medium, provided that you -conspicuously and appropriately publish on each copy an appropriate -copyright notice and disclaimer of warranty; keep intact all the -notices that refer to this License and to the absence of any warranty; -and give any other recipients of the Program a copy of this License -along with the Program. - -You may charge a fee for the physical act of transferring a copy, and -you may at your option offer warranty protection in exchange for a fee. - -@item -You may modify your copy or copies of the Program or any portion -of it, thus forming a work based on the Program, and copy and -distribute such modifications or work under the terms of Section 1 -above, provided that you also meet all of these conditions: - -@enumerate a -@item -You must cause the modified files to carry prominent notices -stating that you changed the files and the date of any change. - -@item -You must cause any work that you distribute or publish, that in -whole or in part contains or is derived from the Program or any -part thereof, to be licensed as a whole at no charge to all third -parties under the terms of this License. - -@item -If the modified program normally reads commands interactively -when run, you must cause it, when started running for such -interactive use in the most ordinary way, to print or display an -announcement including an appropriate copyright notice and a -notice that there is no warranty (or else, saying that you provide -a warranty) and that users may redistribute the program under -these conditions, and telling the user how to view a copy of this -License. (Exception: if the Program itself is interactive but -does not normally print such an announcement, your work based on -the Program is not required to print an announcement.) -@end enumerate - -These requirements apply to the modified work as a whole. If -identifiable sections of that work are not derived from the Program, -and can be reasonably considered independent and separate works in -themselves, then this License, and its terms, do not apply to those -sections when you distribute them as separate works. But when you -distribute the same sections as part of a whole which is a work based -on the Program, the distribution of the whole must be on the terms of -this License, whose permissions for other licensees extend to the -entire whole, and thus to each and every part regardless of who wrote it. - -Thus, it is not the intent of this section to claim rights or contest -your rights to work written entirely by you; rather, the intent is to -exercise the right to control the distribution of derivative or -collective works based on the Program. - -In addition, mere aggregation of another work not based on the Program -with the Program (or with a work based on the Program) on a volume of -a storage or distribution medium does not bring the other work under -the scope of this License. - -@item -You may copy and distribute the Program (or a work based on it, -under Section 2) in object code or executable form under the terms of -Sections 1 and 2 above provided that you also do one of the following: - -@enumerate a -@item -Accompany it with the complete corresponding machine-readable -source code, which must be distributed under the terms of Sections -1 and 2 above on a medium customarily used for software interchange; or, - -@item -Accompany it with a written offer, valid for at least three -years, to give any third party, for a charge no more than your -cost of physically performing source distribution, a complete -machine-readable copy of the corresponding source code, to be -distributed under the terms of Sections 1 and 2 above on a medium -customarily used for software interchange; or, - -@item -Accompany it with the information you received as to the offer -to distribute corresponding source code. (This alternative is -allowed only for noncommercial distribution and only if you -received the program in object code or executable form with such -an offer, in accord with Subsection b above.) -@end enumerate - -The source code for a work means the preferred form of the work for -making modifications to it. For an executable work, complete source -code means all the source code for all modules it contains, plus any -associated interface definition files, plus the scripts used to -control compilation and installation of the executable. However, as a -special exception, the source code distributed need not include -anything that is normally distributed (in either source or binary -form) with the major components (compiler, kernel, and so on) of the -operating system on which the executable runs, unless that component -itself accompanies the executable. - -If distribution of executable or object code is made by offering -access to copy from a designated place, then offering equivalent -access to copy the source code from the same place counts as -distribution of the source code, even though third parties are not -compelled to copy the source along with the object code. - -@item -You may not copy, modify, sublicense, or distribute the Program -except as expressly provided under this License. Any attempt -otherwise to copy, modify, sublicense or distribute the Program is -void, and will automatically terminate your rights under this License. -However, parties who have received copies, or rights, from you under -this License will not have their licenses terminated so long as such -parties remain in full compliance. - -@item -You are not required to accept this License, since you have not -signed it. However, nothing else grants you permission to modify or -distribute the Program or its derivative works. These actions are -prohibited by law if you do not accept this License. Therefore, by -modifying or distributing the Program (or any work based on the -Program), you indicate your acceptance of this License to do so, and -all its terms and conditions for copying, distributing or modifying -the Program or works based on it. - -@item -Each time you redistribute the Program (or any work based on the -Program), the recipient automatically receives a license from the -original licensor to copy, distribute or modify the Program subject to -these terms and conditions. You may not impose any further -restrictions on the recipients' exercise of the rights granted herein. -You are not responsible for enforcing compliance by third parties to -this License. - -@item -If, as a consequence of a court judgment or allegation of patent -infringement or for any other reason (not limited to patent issues), -conditions are imposed on you (whether by court order, agreement or -otherwise) that contradict the conditions of this License, they do not -excuse you from the conditions of this License. If you cannot -distribute so as to satisfy simultaneously your obligations under this -License and any other pertinent obligations, then as a consequence you -may not distribute the Program at all. For example, if a patent -license would not permit royalty-free redistribution of the Program by -all those who receive copies directly or indirectly through you, then -the only way you could satisfy both it and this License would be to -refrain entirely from distribution of the Program. - -If any portion of this section is held invalid or unenforceable under -any particular circumstance, the balance of the section is intended to -apply and the section as a whole is intended to apply in other -circumstances. - -It is not the purpose of this section to induce you to infringe any -patents or other property right claims or to contest validity of any -such claims; this section has the sole purpose of protecting the -integrity of the free software distribution system, which is -implemented by public license practices. Many people have made -generous contributions to the wide range of software distributed -through that system in reliance on consistent application of that -system; it is up to the author/donor to decide if he or she is willing -to distribute software through any other system and a licensee cannot -impose that choice. - -This section is intended to make thoroughly clear what is believed to -be a consequence of the rest of this License. - -@item -If the distribution and/or use of the Program is restricted in -certain countries either by patents or by copyrighted interfaces, the -original copyright holder who places the Program under this License -may add an explicit geographical distribution limitation excluding -those countries, so that distribution is permitted only in or among -countries not thus excluded. In such case, this License incorporates -the limitation as if written in the body of this License. - -@item -The Free Software Foundation may publish revised and/or new versions -of the General Public License from time to time. Such new versions will -be similar in spirit to the present version, but may differ in detail to -address new problems or concerns. - -Each version is given a distinguishing version number. If the Program -specifies a version number of this License which applies to it and ``any -later version'', you have the option of following the terms and conditions -either of that version or of any later version published by the Free -Software Foundation. If the Program does not specify a version number of -this License, you may choose any version ever published by the Free Software -Foundation. - -@item -If you wish to incorporate parts of the Program into other free -programs whose distribution conditions are different, write to the author -to ask for permission. For software which is copyrighted by the Free -Software Foundation, write to the Free Software Foundation; we sometimes -make exceptions for this. Our decision will be guided by the two goals -of preserving the free status of all derivatives of our free software and -of promoting the sharing and reuse of software generally. - -@iftex -@heading NO WARRANTY -@end iftex -@ifinfo -@center NO WARRANTY -@end ifinfo - -@item -BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY -FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW@. EXCEPT WHEN -OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES -PROVIDE THE PROGRAM ``AS IS'' WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED -OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF -MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE@. THE ENTIRE RISK AS -TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU@. SHOULD THE -PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, -REPAIR OR CORRECTION. - -@item -IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING -WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR -REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, -INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING -OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED -TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY -YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER -PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE -POSSIBILITY OF SUCH DAMAGES. -@end enumerate - -@iftex -@heading END OF TERMS AND CONDITIONS -@end iftex -@ifinfo -@center END OF TERMS AND CONDITIONS -@end ifinfo - -@page -@unnumberedsec How to Apply These Terms to Your New Programs - - If you develop a new program, and you want it to be of the greatest -possible use to the public, the best way to achieve this is to make it -free software which everyone can redistribute and change under these terms. - - To do so, attach the following notices to the program. It is safest -to attach them to the start of each source file to most effectively -convey the exclusion of warranty; and each file should have at least -the ``copyright'' line and a pointer to where the full notice is found. - -@smallexample -@var{one line to give the program's name and an idea of what it does.} -Copyright (C) 19@var{yy} @var{name of author} - -This program is free software; you can redistribute it and/or -modify it under the terms of the GNU General Public License -as published by the Free Software Foundation; either version 2 -of the License, or (at your option) any later version. - -This program is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE@. See the -GNU General Public License for more details. - -You should have received a copy of the GNU General Public License -along with this program; if not, write to the Free Software -Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. -@end smallexample - -Also add information on how to contact you by electronic and paper mail. - -If the program is interactive, make it output a short notice like this -when it starts in an interactive mode: - -@smallexample -Gnomovision version 69, Copyright (C) 19@var{yy} @var{name of author} -Gnomovision comes with ABSOLUTELY NO WARRANTY; for details -type `show w'. This is free software, and you are welcome -to redistribute it under certain conditions; type `show c' -for details. -@end smallexample - -The hypothetical commands @samp{show w} and @samp{show c} should show -the appropriate parts of the General Public License. Of course, the -commands you use may be called something other than @samp{show w} and -@samp{show c}; they could even be mouse-clicks or menu items---whatever -suits your program. - -You should also get your employer (if you work as a programmer) or your -school, if any, to sign a ``copyright disclaimer'' for the program, if -necessary. Here is a sample; alter the names: - -@smallexample -@group -Yoyodyne, Inc., hereby disclaims all copyright -interest in the program `Gnomovision' -(which makes passes at compilers) written -by James Hacker. - -@var{signature of Ty Coon}, 1 April 1989 -Ty Coon, President of Vice -@end group -@end smallexample - -This General Public License does not permit incorporating your program into -proprietary programs. If your program is a subroutine library, you may -consider it more useful to permit linking proprietary applications with the -library. If this is what you want to do, use the GNU Library General -Public License instead of this License. - -@node Introduction, Lisp Data Types, Copying, Top -@chapter Introduction - - Most of the GNU Emacs text editor is written in the programming -language called Emacs Lisp. You can write new code in Emacs Lisp and -install it as an extension to the editor. However, Emacs Lisp is more -than a mere ``extension language''; it is a full computer programming -language in its own right. You can use it as you would any other -programming language. - - Because Emacs Lisp is designed for use in an editor, it has special -features for scanning and parsing text as well as features for handling -files, buffers, displays, subprocesses, and so on. Emacs Lisp is -closely integrated with the editing facilities; thus, editing commands -are functions that can also conveniently be called from Lisp programs, -and parameters for customization are ordinary Lisp variables. - - This manual describes Emacs Lisp, presuming considerable familiarity -with the use of Emacs for editing. (See @cite{The GNU Emacs Manual} -for this basic information.) Generally speaking, the earlier chapters -describe features of Emacs Lisp that have counterparts in many -programming languages, and later chapters describe features that are -peculiar to Emacs Lisp or relate specifically to editing. - - This is edition 2.4. - -@menu -* Caveats:: Flaws and a request for help. -* Lisp History:: Emacs Lisp is descended from Maclisp. -* Conventions:: How the manual is formatted. -* Acknowledgements:: The authors, editors, and sponsors of this manual. -@end menu - -@node Caveats -@section Caveats - - This manual has gone through numerous drafts. It is nearly complete -but not flawless. There are a few topics that are not covered, either -because we consider them secondary (such as most of the individual -modes) or because they are yet to be written. Because we are not able -to deal with them completely, we have left out several parts -intentionally. This includes most information about usage on VMS. - - The manual should be fully correct in what it does cover, and it is -therefore open to criticism on anything it says---from specific examples -and descriptive text, to the ordering of chapters and sections. If -something is confusing, or you find that you have to look at the sources -or experiment to learn something not covered in the manual, then perhaps -the manual should be fixed. Please let us know. - -@iftex - As you use the manual, we ask that you mark pages with corrections so -you can later look them up and send them in. If you think of a simple, -real-life example for a function or group of functions, please make an -effort to write it up and send it in. Please reference any comments to -the chapter name, section name, and function name, as appropriate, since -page numbers and chapter and section numbers will change and we may have -trouble finding the text you are talking about. Also state the number -of the edition you are criticizing. -@end iftex -@ifinfo - -As you use this manual, we ask that you send corrections as soon as you -find them. If you think of a simple, real life example for a function -or group of functions, please make an effort to write it up and send it -in. Please reference any comments to the node name and function or -variable name, as appropriate. Also state the number of the edition -which you are criticizing. -@end ifinfo - -Please mail comments and corrections to - -@example -bug-lisp-manual@@prep.ai.mit.edu -@end example - -@noindent -We let mail to this list accumulate unread until someone decides to -apply the corrections. Months, and sometimes years, go by between -updates. So please attach no significance to the lack of a reply---your -mail @emph{will} be acted on in due time. If you want to contact the -Emacs maintainers more quickly, send mail to -@code{bug-gnu-emacs@@prep.ai.mit.edu}. - -@display - --Bil Lewis, Dan LaLiberte, Richard Stallman -@end display - -@node Lisp History -@section Lisp History -@cindex Lisp history - - Lisp (LISt Processing language) was first developed in the late 1950's -at the Massachusetts Institute of Technology for research in artificial -intelligence. The great power of the Lisp language makes it superior -for other purposes as well, such as writing editing commands. - -@cindex Maclisp -@cindex Common Lisp - Dozens of Lisp implementations have been built over the years, each -with its own idiosyncrasies. Many of them were inspired by Maclisp, -which was written in the 1960's at MIT's Project MAC. Eventually the -implementors of the descendants of Maclisp came together and developed a -standard for Lisp systems, called Common Lisp. - - GNU Emacs Lisp is largely inspired by Maclisp, and a little by Common -Lisp. If you know Common Lisp, you will notice many similarities. -However, many of the features of Common Lisp have been omitted or -simplified in order to reduce the memory requirements of GNU Emacs. -Sometimes the simplifications are so drastic that a Common Lisp user -might be very confused. We will occasionally point out how GNU Emacs -Lisp differs from Common Lisp. If you don't know Common Lisp, don't -worry about it; this manual is self-contained. - -@node Conventions -@section Conventions - -This section explains the notational conventions that are used in this -manual. You may want to skip this section and refer back to it later. - -@menu -* Some Terms:: Explanation of terms we use in this manual. -* nil and t:: How the symbols @code{nil} and @code{t} are used. -* Evaluation Notation:: The format we use for examples of evaluation. -* Printing Notation:: The format we use for examples that print output. -* Error Messages:: The format we use for examples of errors. -* Buffer Text Notation:: The format we use for buffer contents in examples. -* Format of Descriptions:: Notation for describing functions, variables, etc. -@end menu - -@node Some Terms -@subsection Some Terms - - Throughout this manual, the phrases ``the Lisp reader'' and ``the Lisp -printer'' are used to refer to those routines in Lisp that convert -textual representations of Lisp objects into actual Lisp objects, and vice -versa. @xref{Printed Representation}, for more details. You, the -person reading this manual, are thought of as ``the programmer'' and are -addressed as ``you''. ``The user'' is the person who uses Lisp programs, -including those you write. - -@cindex fonts - Examples of Lisp code appear in this font or form: @code{(list 1 2 -3)}. Names that represent arguments or metasyntactic variables appear -in this font or form: @var{first-number}. - -@node nil and t -@subsection @code{nil} and @code{t} -@cindex @code{nil}, uses of -@cindex truth value -@cindex boolean -@cindex false - - In Lisp, the symbol @code{nil} has three separate meanings: it -is a symbol with the name @samp{nil}; it is the logical truth value -@var{false}; and it is the empty list---the list of zero elements. -When used as a variable, @code{nil} always has the value @code{nil}. - - As far as the Lisp reader is concerned, @samp{()} and @samp{nil} are -identical: they stand for the same object, the symbol @code{nil}. The -different ways of writing the symbol are intended entirely for human -readers. After the Lisp reader has read either @samp{()} or @samp{nil}, -there is no way to determine which representation was actually written -by the programmer. - - In this manual, we use @code{()} when we wish to emphasize that it -means the empty list, and we use @code{nil} when we wish to emphasize -that it means the truth value @var{false}. That is a good convention to use -in Lisp programs also. - -@example -(cons 'foo ()) ; @r{Emphasize the empty list} -(not nil) ; @r{Emphasize the truth value @var{false}} -@end example - -@cindex @code{t} and truth -@cindex true - In contexts where a truth value is expected, any non-@code{nil} value -is considered to be @var{true}. However, @code{t} is the preferred way -to represent the truth value @var{true}. When you need to choose a -value which represents @var{true}, and there is no other basis for -choosing, use @code{t}. The symbol @code{t} always has value @code{t}. - - In Emacs Lisp, @code{nil} and @code{t} are special symbols that always -evaluate to themselves. This is so that you do not need to quote them -to use them as constants in a program. An attempt to change their -values results in a @code{setting-constant} error. @xref{Accessing -Variables}. - -@node Evaluation Notation -@subsection Evaluation Notation -@cindex evaluation notation -@cindex documentation notation - - A Lisp expression that you can evaluate is called a @dfn{form}. -Evaluating a form always produces a result, which is a Lisp object. In -the examples in this manual, this is indicated with @samp{@result{}}: - -@example -(car '(1 2)) - @result{} 1 -@end example - -@noindent -You can read this as ``@code{(car '(1 2))} evaluates to 1''. - - When a form is a macro call, it expands into a new form for Lisp to -evaluate. We show the result of the expansion with -@samp{@expansion{}}. We may or may not show the actual result of the -evaluation of the expanded form. - -@example -(third '(a b c)) - @expansion{} (car (cdr (cdr '(a b c)))) - @result{} c -@end example - - Sometimes to help describe one form we show another form that -produces identical results. The exact equivalence of two forms is -indicated with @samp{@equiv{}}. - -@example -(make-sparse-keymap) @equiv{} (list 'keymap) -@end example - -@node Printing Notation -@subsection Printing Notation -@cindex printing notation - - Many of the examples in this manual print text when they are -evaluated. If you execute example code in a Lisp Interaction buffer -(such as the buffer @samp{*scratch*}), the printed text is inserted into -the buffer. If you execute the example by other means (such as by -evaluating the function @code{eval-region}), the printed text is -displayed in the echo area. You should be aware that text displayed in -the echo area is truncated to a single line. - - Examples in this manual indicate printed text with @samp{@print{}}, -irrespective of where that text goes. The value returned by evaluating -the form (here @code{bar}) follows on a separate line. - -@example -@group -(progn (print 'foo) (print 'bar)) - @print{} foo - @print{} bar - @result{} bar -@end group -@end example - -@node Error Messages -@subsection Error Messages -@cindex error message notation - - Some examples signal errors. This normally displays an error message -in the echo area. We show the error message on a line starting with -@samp{@error{}}. Note that @samp{@error{}} itself does not appear in -the echo area. - -@example -(+ 23 'x) -@error{} Wrong type argument: integer-or-marker-p, x -@end example - -@node Buffer Text Notation -@subsection Buffer Text Notation -@cindex buffer text notation - - Some examples show modifications to text in a buffer, with ``before'' -and ``after'' versions of the text. These examples show the contents of -the buffer in question between two lines of dashes containing the buffer -name. In addition, @samp{@point{}} indicates the location of point. -(The symbol for point, of course, is not part of the text in the buffer; -it indicates the place @emph{between} two characters where point is -located.) - -@example ----------- Buffer: foo ---------- -This is the @point{}contents of foo. ----------- Buffer: foo ---------- - -(insert "changed ") - @result{} nil ----------- Buffer: foo ---------- -This is the changed @point{}contents of foo. ----------- Buffer: foo ---------- -@end example - -@node Format of Descriptions -@subsection Format of Descriptions -@cindex description format - - Functions, variables, macros, commands, user options, and special -forms are described in this manual in a uniform format. The first -line of a description contains the name of the item followed by its -arguments, if any. -@ifinfo -The category---function, variable, or whatever---appears at the -beginning of the line. -@end ifinfo -@iftex -The category---function, variable, or whatever---is printed next to the -right margin. -@end iftex -The description follows on succeeding lines, sometimes with examples. - -@menu -* A Sample Function Description:: A description of an imaginary - function, @code{foo}. -* A Sample Variable Description:: A description of an imaginary - variable, - @code{electric-future-map}. -@end menu - -@node A Sample Function Description -@subsubsection A Sample Function Description -@cindex function descriptions -@cindex command descriptions -@cindex macro descriptions -@cindex special form descriptions - - In a function description, the name of the function being described -appears first. It is followed on the same line by a list of parameters. -The names used for the parameters are also used in the body of the -description. - - The appearance of the keyword @code{&optional} in the parameter list -indicates that the arguments for subsequent parameters may be omitted -(omitted parameters default to @code{nil}). Do not write -@code{&optional} when you call the function. - - The keyword @code{&rest} (which will always be followed by a single -parameter) indicates that any number of arguments can follow. The value -of the single following parameter will be a list of all these arguments. -Do not write @code{&rest} when you call the function. - - Here is a description of an imaginary function @code{foo}: - -@defun foo integer1 &optional integer2 &rest integers -The function @code{foo} subtracts @var{integer1} from @var{integer2}, -then adds all the rest of the arguments to the result. If @var{integer2} -is not supplied, then the number 19 is used by default. - -@example -(foo 1 5 3 9) - @result{} 16 -(foo 5) - @result{} 14 -@end example - -More generally, - -@example -(foo @var{w} @var{x} @var{y}@dots{}) -@equiv{} -(+ (- @var{x} @var{w}) @var{y}@dots{}) -@end example -@end defun - - Any parameter whose name contains the name of a type (e.g., -@var{integer}, @var{integer1} or @var{buffer}) is expected to be of that -type. A plural of a type (such as @var{buffers}) often means a list of -objects of that type. Parameters named @var{object} may be of any type. -(@xref{Lisp Data Types}, for a list of Emacs object types.) -Parameters with other sorts of names (e.g., @var{new-file}) are -discussed specifically in the description of the function. In some -sections, features common to parameters of several functions are -described at the beginning. - - @xref{Lambda Expressions}, for a more complete description of optional -and rest arguments. - - Command, macro, and special form descriptions have the same format, -but the word `Function' is replaced by `Command', `Macro', or `Special -Form', respectively. Commands are simply functions that may be called -interactively; macros process their arguments differently from functions -(the arguments are not evaluated), but are presented the same way. - - Special form descriptions use a more complex notation to specify -optional and repeated parameters because they can break the argument -list down into separate arguments in more complicated ways. -@samp{@code{@r{[}@var{optional-arg}@r{]}}} means that @var{optional-arg} is -optional and @samp{@var{repeated-args}@dots{}} stands for zero or more -arguments. Parentheses are used when several arguments are grouped into -additional levels of list structure. Here is an example: - -@defspec count-loop (@var{var} [@var{from} @var{to} [@var{inc}]]) @var{body}@dots{} -This imaginary special form implements a loop that executes the -@var{body} forms and then increments the variable @var{var} on each -iteration. On the first iteration, the variable has the value -@var{from}; on subsequent iterations, it is incremented by 1 (or by -@var{inc} if that is given). The loop exits before executing @var{body} -if @var{var} equals @var{to}. Here is an example: - -@example -(count-loop (i 0 10) - (prin1 i) (princ " ") - (prin1 (aref vector i)) (terpri)) -@end example - -If @var{from} and @var{to} are omitted, then @var{var} is bound to -@code{nil} before the loop begins, and the loop exits if @var{var} is -non-@code{nil} at the beginning of an iteration. Here is an example: - -@example -(count-loop (done) - (if (pending) - (fixit) - (setq done t))) -@end example - -In this special form, the arguments @var{from} and @var{to} are -optional, but must both be present or both absent. If they are present, -@var{inc} may optionally be specified as well. These arguments are -grouped with the argument @var{var} into a list, to distinguish them -from @var{body}, which includes all remaining elements of the form. -@end defspec - -@node A Sample Variable Description -@subsubsection A Sample Variable Description -@cindex variable descriptions -@cindex option descriptions - - A @dfn{variable} is a name that can hold a value. Although any -variable can be set by the user, certain variables that exist -specifically so that users can change them are called @dfn{user -options}. Ordinary variables and user options are described using a -format like that for functions except that there are no arguments. - - Here is a description of the imaginary @code{electric-future-map} -variable.@refill - -@defvar electric-future-map -The value of this variable is a full keymap used by Electric Command -Future mode. The functions in this map allow you to edit commands you -have not yet thought about executing. -@end defvar - - User option descriptions have the same format, but `Variable' is -replaced by `User Option'. - -@node Acknowledgements -@section Acknowledgements - - This manual was written by Robert Krawitz, Bil Lewis, Dan LaLiberte, -Richard M. Stallman and Chris Welty, the volunteers of the GNU manual -group, in an effort extending over several years. Robert J. Chassell -helped to review and edit the manual, with the support of the Defense -Advanced Research Projects Agency, ARPA Order 6082, arranged by Warren -A. Hunt, Jr. of Computational Logic, Inc. - - Corrections were supplied by Karl Berry, Jim Blandy, Bard Bloom, -Stephane Boucher, David Boyes, Alan Carroll, Richard Davis, Lawrence -R. Dodd, Peter Doornbosch, David A. Duff, Chris Eich, Beverly -Erlebacher, David Eckelkamp, Ralf Fassel, Eirik Fuller, Stephen Gildea, -Bob Glickstein, Eric Hanchrow, George Hartzell, Nathan Hess, Masayuki -Ida, Dan Jacobson, Jak Kirman, Bob Knighten, Frederick M. Korz, Joe -Lammens, Glenn M. Lewis, K. Richard Magill, Brian Marick, Roland -McGrath, Skip Montanaro, John Gardiner Myers, Thomas A. Peterson, -Francesco Potorti, Friedrich Pukelsheim, Arnold D. Robbins, Raul -Rockwell, Per Starback, Shinichirou Sugou, Kimmo Suominen, Edward Tharp, -Bill Trost, Rickard Westman, Jean White, Matthew Wilding, Carl Witty, -Dale Worley, Rusty Wright, and David D. Zuhn. |