\input texinfo @c -*-texinfo-*- @comment %**start of header (This is for running Texinfo on a region.) @setfilename bigforth.info @settitle bigFORTH/MINOS Manual @dircategory GNU programming tools @direntry * bigFORTH: (bigforth). A fast interpreter for the Forth language. @end direntry @comment @setchapternewpage odd @comment TODO this gets left in by HTML converter @macro progstyle {} Programming style note: @end macro @comment %**end of header (This is for running Texinfo on a region.) @include version.texi @ifinfo This file documents bigFORTH/MINOS @value{VERSION} Copyright @copyright{} 1995-1999 Free Software Foundation, Inc. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. @ignore Permission is granted to process this file through TeX and print the results, provided the printed document carries a copying permission notice identical to this one except for the removal of this paragraph (this paragraph not being relevant to the printed manual). @end ignore Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the sections entitled "Distribution" and "General Public License" are included exactly as in the original, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that the sections entitled "Distribution" and "General Public License" may be included in a translation approved by the author instead of in the original English. @end ifinfo @finalout @titlepage @sp 10 @center @titlefont{bigFORTH/MINOS Manual} @sp 2 @center for version @value{VERSION} @sp 2 @center Bernd Paysan @sp 3 @center This manual is permanently under construction and was last updated on 21-August-1999 @end titlepage @node Top, MINOS Documentation,, (dir) @ifinfo Gforth is a free implementation of ANS Forth available on many personal machines. This manual corresponds to version @value{VERSION}. @end ifinfo @menu * MINOS Documentation:: The documentation of the MINOS widget set * Theseus Tutorial:: A tutorial introducing into Theseus * License:: The GPL @end menu @node MINOS Documentation, Theseus Tutorial , Top, Top @chapter MINOS Documentation @menu * Introduction:: Oh no, it's Forth again... * Widget Classes:: The Widget Set of MINOS. @end menu @node Introduction, Widget Classes, MINOS Documentation, MINOS Documentation @section Introduction @menu * Abstract:: What MINOS is. * WYSIWYD:: What You See Is What You Do. * Visual Forth:: The Man Month Myth. * Codename MINOS:: Where the Name come from. * Windoze:: Porting Notes. @end menu @node Abstract, WYSIWYD, Introduction, Introduction @subsection Abstract MINOS is the answer to the question ``Is there something like Visual BASIC (Microsoft) or Delphi (Inprise) in Forth?'' --- and the answer is ``yes''. Basically, these GUI RADs contain two components: a library with a wide variety of elements for a graphical user interface; e.g. windows, buttons, edit-controls, drawing areas, etc.; and an editor to combine the elements with the mouse by drag&drop or click&point actions. Missing code then is inserted to add actions when buttons are pressed. Typical applications are often related to data base access. Therefore, many of these systems already contain a data base engine or at least a standardized interface to a data base, such as ODBC. Another aspect are complex components. With some of these toolkits, you can create a web browser with some mouse clicks and a few keystrokes. However, these components hide their details, a shrink wrapped web browser application is not necessarily worse. The interactivity of these tools usually is not very high. You create your form, write your actions as code and compile it more (Delphi) or less (Visual Age for C++) fast. Trying it usually isn't possible before the compiler run. @node WYSIWYD, Visual Forth, Abstract, Introduction @subsection WYSIWYD It isn't really necessary to brush graphical user interfaces together, as it isn't to edit texts WYSIWYG. Many typesetting functions are more semantically than visual, e.g. a text is a headline or emphasized instead of written in bold 18 point Garamond or 11 point Roman italics. All this is true for user interfaces, to some extend much more. It's not the programmer that decides which font and size to use for the UI --- that's up to the user. As is color of buttons and texts. Also to layout individual widgets, more abstraction than defining position, width and height makes sense. Typically buttons are arranged horizontally or vertically, perhaps with a bit distance between them. The size of buttons must follow the containing strings, and should conform to aesthetics (e.g. each button in a row has the same width). Such an abstract model, related to TeX's boxes&glues, programs quite good even without a visual editor. The programmer isn't responsible for ``typesetting'' the buttons and boxes. This approach is quite usual in Unix. Motif and Tcl/Tk use neighborhood relations, Interviews uses boxes&glues. I decided for boxes&glues, since it's a fast and intuitive solution, although it needs more objects to get the same result. These concepts contradict somehow with a graphical editing process, since the editors I know don't provide abstract concepts (``place left of an object'' or ``place in a row''), but positions. @node Visual Forth, Codename MINOS, WYSIWYD, Introduction @subsection Visual Forth One point makes me think: the packets that allow real visual form programming have many years of programming invested in. Microsoft, Borland, and IBM may hire hundreds of programmers just for one such project. This man-power isn't available for any Forth project. But stop: @enumerate 1 @item Forth claims that good programmers can work much more efficient with Forth @item A team of 300 (wo)men blocks itself. If the boss partitions the work, the programmers need to document functions, and to read documents from other programmer related to other functions and must understand them, or ask questions to figure things out. Everybody knows that documenting takes much longer than writing the code, and explaining is even worse. Thus at a certain project complexity level, no time is left for the programming task; all time is used to specify planned functions and read the specification from other programmers. Or the programmers just chat before the door holes of the much too small and noisy cubicles. @item A good programmer reportedly works 20 times as fast as a bad, even though he can't type in more key strokes per time. The resulting program is either up to 20 times shorter or has 20 times less bugs (or both) --- with more functionality at the same time. Teamwork however prevents good programmers from work, since they are frustrated by bad programmers surrounding them, from their inability to produce required information in time; and the bad programmers are frustrated by the good ones, which makes them even worse. @item Therefore, even in large projects, the real work is (or should be) done by a small ``core team''. Then the Dilbert rule applies: what can be done with two people, can be done with one at half of the costs. @end enumerate Furthermore, bigFORTH-DOS already contains a ``Text-GUI'', without graphical editor, but with an abstract boxes&glue concept, which, as claimed above, hinders the use of such an editor. Finally I wanted to get rid of DOS, and port bigFORTH to a real operating system (Linux). In contrast to Windows and OS/2, user interface and screen access are separated there. Drawing on the screen uses the X Window System (short X), the actual user interface is implemented in a library. This is the reason, why there is no common interface, but a lot of different libraries, such as Athena Widgets, Motif, Tcl/Tk, xforms, Qt, gtk, and others. The ``look and feel'' from Motif-like buttons is quite common, even Windows and MacOS resemble it. All these libraries have disadvantages. The Athena Widgets are hopelessly outdated. Motif is commercial, even if a free clone (Lesstif) is in creation. It's slow and a memory hog. Tcl/Tk consumes less memory, but it's @emph{even} slower. How do you explain your users that drawing a window takes seconds, while Quake renders animated 3D-graphic on the same machine? Qt is fast, but it's written in C++ and doesn't have a foreign language interface now. gtk, the GIMP toolkit, has more foreign language interfaces, and it's free, but it wasn't available until recently. Therefore I decided to port the widget classes from bigFORTH-DOS to X, and write an editor for it. Such classes written in Forth naturally fit in an development environment and are --- from the Forth point of view --- easier to maintain. There are not such many widget libraries in C, because it's a task written in an afternoon, but because the available didn't fit the requests, and a modification looked desperate. @node Codename MINOS, Windoze , Visual Forth, Introduction @subsection Codename MINOS ``Visual XXX'' is an all day's name, and it's too much of a microsoftism for me. ``Forth'' is a no-word, especially since the future market consists of one billion Chinese, and for them four is a number of unluck (because ``se'' (four) sounds much like ``se'' (death)). However, even Borland doesn't call their system ``Visual TurboPascal'', but ``Delphi''. Greek is good, anyway, since this library relates to the boxes&glues model of TeX, which is pronounced Greek, too. Compared with Motif, the library is quite copact (MINimal), and since it's mainly for Linux, the phonetic distance is small... I pronounce it Greek: ``meenoz''. @node Windoze , , Codename MINOS, Introduction @subsection Windoze I ported MINOS to Windows 95/NT, on the demand of some potential users. It doesn't run near as stable as under Linux/X, since there are a hideous number of subtle bugs in Windows, and I don't have the time to work around all of them. Drawing polygons doesn't work as well as on X, and all the bugs that are in the memory drawing device can drive me nuts. The Windows port of MINOS looks more like the ``modern Forth'' Claus Vogt portrayed in @url{news:de.comp.lang.forth}: it shows random general protection faults. Well, just like any other Windows program. @node Widget Classes, , Introduction, MINOS Documentation @section Widget Classes The primary classes of MINOS are gadgets (widgets and displays), actors, and resources (xresource and font). Resources just provide system-specific data like window handles, display pointers, font informations, etc., they are critical for system-specific parts of display implementations. Widgets are the central objects represented on screen. Widgets draw through displays, such as windows, viewports, etc. Since many displays can be embedded into a bigger window, they also have all widget functionality. Widgets are composed in boxes (horizontal and vertical), and automatically layouted. Boxes certainly are widgets themselves, and some of the more complicated widgets such as sliders or textboxes are derived from boxes to layout the inner parts easily. Actors are bound to associated actions when operating a widget (i.e. clicking on it, pointing on it, or entering text). Actors provide the way to script actions. @menu * Actors:: * Ressources:: * Widgets:: * Boxes:: * Displays:: @end menu @node Actors, Ressources, Widget Classes, Widget Classes @subsection Actors @b{ACTOR} @itemize @bullet @item All Actors have the following methods in common: @itemize @bullet @item @b{called} This variable points to the object that is being called @item @b{caller} This variable points to the object that is calling (the widget). @item @b{set} ( --- ) sets the flag @item @b{reset} ( --- ) resets the flag @item @b{toggle} ( --- ) toggles the flag @item @b{fetch} ( --- x1 .. xn ) queries the value(s) @item @b{store} ( x1 .. xn --- ) changes the value(s) @item @b{click} ( x y b n --- ) performs the action for a click @item @b{key} ( key sh --- ) performs the action for a keystroke @item @b{enter} ( --- ) performs the action for entering the widget @item @b{leave} ( --- ) performs the action for leaving the widget @item @b{assign} ( x1 .. xn --- ) initially assigns the state @item @b{set-called} ( o --- ) sets the called object @end itemize The stack effect you see below is the stack effect of the init method. @item @b{KEY-ACTOR} This is an actor for keyboard macros. It inserts keystrokes into the called widget. @item @b{TOOLTIP} ( actor tip --- ) A tooltip is a nested actor; it shows the widget tip some time after entering with the mouse, and forwards the other messages to actor @item @b{EDIT-ACTION} ( o xt --- ) This actor handles text input field key events, and does all the editing stuff. After each keystroke and each click, it calls xt ( --- ). @itemize @bullet @item @b{NUMBER-ACTION} ( o xt --- ) Same as EDIT-ACTION, but filters out digits only @end itemize @item @b{SCALE-VAR} ( o pos max --- ) Scaler actor, keeps position and maximum value in own variables. @itemize @bullet @item @b{SCALE-DO} ( o pos max xt --- ) Same as SCALE-VAR, but executes xt ( pos --- ) on changes @item @b{SLIDER-VAR} ( o pos max step --- ) Slider actor, keeps position, step, and maximum value in own variables @itemize @bullet @item @b{SLIDER-DO} ( o pos max step xt --- ) Same as SLIDER-VAR, but executes xt ( --- ) on changes @end itemize @end itemize @item @b{SIMPLE} ( o xt --- ) xt is executed at every store (no state maintained) @itemize @bullet @item @b{DRAG} ( o xt --- ) Calls toggle on each click event @item @b{REP} ( o xt --- ) Calls toggle repeatedly while the user holds down the mouse button @end itemize @item @b{TOGGLE-STATE} ( o xtstore xtfetch --- ) allows generic fetch and store functions @itemize @bullet @item @b{SCALE-ACT} ( o do-store do-fetch max --- ) Generic slider actor (maximum slider position provided) @itemize @bullet @item @b{SLIDER-ACT} ( o do-store do-fetch max --- ) Generic scaler actor (maximum scaler position provided) @end itemize @end itemize @item @b{TOGGLE-VAR} ( o addr xt --- ) keeps the flag in addr, and executes xt on changes @itemize @bullet @item @b{TOGGLE-NUM} ( o n addr xt --- ) is responsible for state n in addr (sets addr to n when set), and executes xt on changes @end itemize @item @b{TOGGLE} ( o state xtset xtreset --- ) models a flag with initial state and two functions for each state @end itemize @node Ressources, Widgets, Actors, Widget Classes @subsection Resources @b{XRESOURCE} @b{FONT} @itemize @bullet @item @b{X-FONT} @end itemize @node Widgets, Boxes, Ressources, Widget Classes @subsection Widgets @b{GADGET} @itemize @bullet @item @b{WIDGET} @itemize @bullet @item @b{TERMINAL} @itemize @bullet @item @b{SCREDIT} @itemize @bullet @item @b{STREDIT} @end itemize @end itemize @end itemize @item @b{ARULE} @itemize @bullet @item @b{BOXCHAR} @itemize @bullet @item @b{HRTSIZER} @itemize @bullet @item @b{HXRTSIZER} @item @b{HSIZER} @end itemize @item @b{VRTSIZER} @itemize @bullet @item @b{VXRTSIZER} @item @b{VSIZER} @end itemize @item @b{BUTTON} @itemize @bullet @item @b{ALERTBUTTON} @item @b{MENU-ENTRY} @itemize @bullet @item @b{EDIMENU-ENTRY} @itemize @bullet @item @b{MENU-TITLE} @item @b{SUB-MENU} @end itemize @end itemize @item @b{(TEXTFIELD} @itemize @bullet @item @b{ICON-BUTTON} @itemize @bullet @item @b{BIG-ICON} @item @b{ICON-BUT} @end itemize @end itemize @item @b{LBUTTON} @itemize @bullet @item @b{FILE-WIDGET} @itemize @bullet @item @b{TEXT-LABEL} @itemize @bullet @item @b{MENU-LABEL} @end itemize @end itemize @end itemize @end itemize @item @b{TOGGLECHAR} @itemize @bullet @item @b{FLIPICON} @item @b{TOGGLEICON} @item @b{TBUTTON} @itemize @bullet @item @b{TICONBUTTON} @item @b{TOGGLEBUTTON} @item @b{TOPINDEX} @item @b{FLIPBUTTON} @item @b{RBUTTON} @end itemize @end itemize @item @b{TRIBUTTON} @itemize @bullet @item @b{SLIDETRI} @end itemize @end itemize @end itemize @end itemize @node Boxes, Displays, Widgets, Widget Classes @subsection Boxes @example COMBINED 44 E4 40139938 VBOX 44 E4 4013B15C SLIDERVIEW 4C E8 40146360 ASLIDERVIEW 4C E8 40146C2C VSLIDER 44 E8 401423B4 VSCALER 50 EC 401434F4 VSLIDER0 44 E8 40142B74 VRBOX 44 E4 40140E74 VTBOX 44 E4 4013C59C VRTBOX 44 E4 4014163C VATBOX 44 E4 4013CB70 VARTBOX 44 E4 40141760 COMPONENT 44 E4 4013BC8C VASBOX 4C E8 40147340 VRESIZE 44 E4 40146FF0 MODAL 48 E4 401418AC VARBOX 44 E4 40141058 HBOX 44 E4 4013A84C INFO-MENU 54 E4 4014CA70 HSLIDER 44 E8 40141D94 HSCALER 50 EC 40142E98 HSLIDER0 44 E8 4014292C HRBOX 44 E4 401411B8 HTBOX 44 E4 4013C0E8 HRTBOX 44 E4 401413F8 HATBOX 44 E4 4013CA50 HARTBOX 44 E4 4014151C HABOX 44 E4 4013BFC8 HASBOX 4C E8 40147558 HRESIZE 44 E4 40147138 HARBOX 44 E4 401412D8 TEXTFIELD 48 E4 40140A08 INFOTEXTFIELD 4C E4 40140C38 (NIL 24 C8 40137B80 GLUE 34 C8 401379F8 GLCANVAS 58 CC 4014B670 RULE 38 C8 40138458 CANVAS 78 118 40138FCC MFILL 38 C8 40138A48 MSKIP 38 C8 40138908 SSKIP 40 C8 40146178 VRULE 38 C8 40138734 HRULE 38 C8 40138618 VGLUE 34 C8 40138308 HGLUE 34 C8 401381EC TOPGLUE 34 C8 4013E908 ICON 28 C8 401377E4 ICON-PIXMAP 2C CC 4013761C @end example @node Displays,, Boxes, Widget Classes @subsection Displays @example DISPLAYS 90 178 4012FC60 WINDOW A4 194 40148B18 FILE-SELECTOR C4 198 40151AB8 MENU-WINDOW A4 194 4014D09C FRAME A8 1A4 4014A698 MENU-FRAME A8 1A4 4014C0D0 FRAME-TIP AC 1A4 4014AD94 WINDOW-STUB A4 194 4014A2C0 (NILSCREEN 90 178 40137D00 BACKING A8 17C 40131DD0 VIEWPORT E0 190 40143EB4 SCRVIEWPORT E0 190 40123590 HVIEWPORT E8 190 40145F14 VVIEWPORT E8 190 40145CC4 BEAMER B8 180 401330F8 DOUBLEBUFFER A8 17C 40132DB0 ok @end example @node Theseus Tutorial, License, MINOS Documentation, Top @section Theseus Tutorial @ifinfo Only a ToDo until yet. @end ifinfo @node License, , Theseus Tutorial, Top @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 a brief 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 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 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. @contents @bye