A User's Manual for GNU Emacs' Web-mode
Contents
1. 21 22 23 24 25 26 David R Hanson Literate Programming Printing Common Words Com munications of the ACM vol 30 no 7 Jul 1987 pp 594 599 Michael A Jackson Literate Programming Processing Transactions Com munications of the ACM vol 30 no 12 Dec 1987 pp 1000 1010 Donald E Knuth METAFONT The Program vol D of Computers amp Type setting Reading MA Addison Wesley Publishing Co 1986 Donald E Knuth TX The Program vol B of Computers amp Typesetting Reading MA Addison Wesley Publishing Co 1986 Donald E Knuth The WEB System of Structured Documentation Stanford Computer Science Report STAN CS 980 Dept of Computer Science Stan ford University Stanford CA Sep 1983 John A Krommes The WEB System of Structured Software Design and Doc umentation for Fortran Ratfor and C Technical Report Princeton Uni versity Princeton NJ Nov 1989 Available by anonymous ftp from ly man pppl gov in directory pub fweb Silvio Levy WEB Adapted to C Another Approach TUGboat vol 8 no 1 Apr 1987 pp 12 13 Donald C Lindsay Literate Programming A File Difference Program Communications of the ACM vol 32 no 6 Jun 1989 pp 740 752 Charles Lins A First Look at Literate Programming Structured Program ming vol 10 no 1 1989 pp 60 62 Charles Lins An Introduction to Literate Programming Structured Pro gramm2. Edit the emacs file to reflect the name of the directory If it did not change then you don t have to edit it Appendix E is a more detailed description of this file and changes you can make 3 Issue the command M x byte compile file The user will be prompted for the name of the file Respond with web mode el This will create a new file named web mode elc Now make sure that everybody can read and execute the files you have in this directory Everybody with the same emacs file in their home directory will automatically be able to use web mode with their files ending in web or w 4 You may have to make some changes as detailed in Appendix E CAVEAT Some of these functions may seem to be trivial and slow at first We believe they will pay big dividends for larger WEBs Getting Started The purpose of web mode is to assist in creating and editing WEBs Creating a New WEB If a WEB is being created Emacs will need to be started with an empty file For example if the name of the new WEB is my web you would enter the UNIX command emacs my web The function web mode will prompt the user for the name of the file that contains the limbo portion of the WEB To accept the default file Limbo material the user need only press the return key If on the other hand the user wishes to enter the name of another file that can be done by answering with another file name If the default is selected the contents of the file limb
3. next press the x key finally enter the characters find file followed by a carriage return An alternate way of issuing this command is to use its associated keybinding as shown in the box to the right of the command above In this keybinding C refers to the CTRL key Press and hold down the CTRL key and then press the x key followed by holding down the CTRL key and then pressing the f key For all commands mentioned throughout this manual both forms of invoking the command will be shown if they exist Some commands such as M x what line do not have a keybinding and hence must be entered by typing in the command name All commands that are WEB extensions have been prefixed with web The outline mode commands violate this INSTALLATION The installation instructions are really quite simple To simplify this manual we will assume that these instructions are followed The files emacs limbo sty and limbo material are attached to the source of this T X file for ease in distribution This began with release 1 6 Of course these are the versions normally used at Texas A amp M and should be adapted to your site s 1 Select a directory for the home of these files which can be shared by all users we use usr local lib web Extract web mode el limbo material and limbo sty from the source of this manual after the bye and place them in that directory 2 Extract emacs from the same source and place it in your home directory
4. file named containing limbo material The name is set in the emacs file limbo material A set of TFX material that aids in the complete presentation of a WEB The distributed limbo material includes source for a title abstract author and other handy information minibuffer The bottom line of the screen when using Emacs This area is used to display arguments to commands commands that are typed in from the keyboard and messages to the user For commands that require arguments the minibuffer area can be used for prompting as well numeric argument A number which is specified before a command to alter the effect of the command section A section begins with the pair of symbols or A section ends when the next section begins or the end of the file whichever comes first If it begins with an it will be called a chapter 27 section name Code portions of sections which begin lt Name of a section gt define the section name by the strings between the lt and gt delimiters Thus section names are pseudocode descriptions of code function web file contains the source of the WEB The file consists of the limbo portion and the individual units that comprise the WEB called sections A section consists of a commentary definition and code parts any two of which can be empty 28
5. prime number If p n is a factor of jl set j_prime false Increase j until it is the next prime number Initialize the data structures Other constants of the program Output a line of answers Output a page of answers Print table Ipl Print the first m prime numbers Program to print the first thousand prime numbers Displaying 11 Section Names of 14 x Emacs Section Names Web Al1 Figure 1 Section names for Knuth s primes web A OC If this abort option is selected the user is switched back to the buffer containing the WEB document and the two characters preceding point lt are deleted The remaining options involve the list of section names The section names are displayed below the menu choices The section names are displayed in alphabetical order and are retrieved from the list that was created when web mode was invoked at the beginning of the editing session Also additional names are inserted in the list as they are created in an editing session C If the option is chosen the user is prompted for the name of the new sec tion Once entered the user is switched back to the buffer containing the WEB document the new section name is inserted and the ending section delimiter either gt or gt is determined automatically and inserted A check against the existing section names is conducted to ensure that the entered section name is indeed new If the section name is new a de
6. value 22 Appendix C Changes To The WEB Processors One of the best things to do in software is to reuse effective and correct code The use of the index is one of the best parts of the WEB system It did not take long for us to decide that we saw no reason for Mark to write lots of elisp code to produce an index when it was already produced by the WEAVE processors To facilitate the reuse of this a little more it was decided to have jobname idx and jobname scn written separately The first is used by web mode while the second is not A companion file to this distribution is changes ch which includes the changes necessary to the most popular WEAVE processors Short comments about these contents follow In the original WEAVE module 239 must be edited The current version of this code is 4 7 Another alternative for users of the original WEAVE is available in the code Look for the string Gragert if you wish to use this and not make these changes Version 2 9 and later versions of CWEB do not require changes At this writing no code changes are required for FWEB The current version of this code is 1 23 Edit fweb sty to get the desired results with FWEAVE It should look in part like this index tex idx modules tex scn contents tex cts 23 Appendix D Debugging Hopefully This will be a pot pourri of notes that may help some unsuspecting user solve some problems that occur in the use of web mode T
7. A User s Manual for GNU Emacs Web mode Mark Motl amp Bart Childs Department of Computer Science T gXas A amp M University Revision 2 00 April 17 1993 This document is a companion to web mode el a collection of GNU Emacs Lisp functions designed to customize GNU Emacs so that it is sensitive to a WEB document Appendix A contains lists of the interactive functions in two formats Most of these have convenient key bindings It is assumed that the reader is already familiar with the WEB style of literate programming the general format of a WEB source and the rules of WEB FWEB CWEB or a similar one The intent in the design of web mode is sensitivity to WEB independent of the high level language Thus it works with Knuth s original WEB with Pascal CWEB FWEB and similar ones The basic Emacs functionality is maintained along with showing matched delimiters and continuing indentation The functions that web mode provides include the indices of variables and sec tions provided by WEAVE outline editing navigation by chapter and section preload ing the search string when using indices automatic completition in some places Throughout this document I will use the symbology used by Emacs For example the find file command can be entered two different ways M x find file The first way of entering the command is to actually type the command as shown above Press the META key on some terminals this may be the ESC key
8. E A user can also display the list of section names that is maintained by web mode It is also possible to view the names of the chapters of the WEB and the section number where each chapter begins Viewing the Index The user can view the contents of the index created by WEAVE by issuing the command M x web view index The user is first asked whether the WEB is a Pascal CWEB or FWEB After the language has been determined the function creates an asynchronous process which invokes the WEAVE processor on the WEB in the current buffer Once this process has com pleted the contents of jobname idx are inserted into another buffer see Figure 2 Some reformatting is done for a better presentation The user can traverse the list of section numbers for a particular index entry by positioning the point anywhere on the line s where the index entry of interest is located and issuing the commands M x web next index C c ni M x web previous index C c pi These commands can be issued from the buffer where the index is displayed or they can be issued from the buffer that contains the WEB document If the commands are issued from the former the user is switched back to the buffer that contains the WEB document and point is positioned at the beginning of the section where the most recently selected index entry was next or previously referenced from point s current position Tmportant The web view index has calls to the Emacs function call pr
9. ands ete Gets ewe edn Cees Cbbe Cobi Cob mege Cege megs ie gn ceil C x tne ene end Cens Ceni Cens Cenu Cepe Cepe Cepa epi eps Cepu Gers eve eve evi Ceve ewe Cews 19 Listing of Web mode Commands by Functionality Functionality Key Binding web goto buffer change file web goto buffer include file web goto buffer web file web goto section named Movement Among web goto section Sections web next section web previous section Interactive Access to web goto chapter and web next chapter Movement Among web previous chapter Chapters web view chapter titles list web next index Movement Among Buffers Files Interactive Access to web previous index Index web view index web next define Interactive Access web next use to Sections web previous define web previous use web view section names list aaaaa web edit section Change File web goto edited section Editing amp Movement web next edited section web previous edited section web count edited sections web count sections web count chapters web delimiter match check web view edited sections list web which edited section web which section web which chapter qaaaajaaaa Web Structure Information Q web insert index entry Miscellaneous web mode save buffers kill emacs web rename section P Q 20 Listing of Web mode Commands by Functionality Functionality Key Bindin Outlining the hide body C chb Whole Buffe
10. asic element of a WEB is a section which is roughly parallel to a paragraph in a book The major sections or group of sections corresponds to a chapter in a book Chapter titles will be in the table of contents We have an extension of the book model in that many sections will have names that will appear in an index Technical books may have subjects of paragraphs in an index Movement Within the WEB The user can goto any section or chapter at any time by issuing either M x web goto section M x web goto chapter respectively The user is then prompted for the section or chapter number If a nonpositive number or a number greater than the number of sections or chapters in the WEB is entered an appropriate error message is displayed in the minibuffer If a valid section or chapter number is entered point moves to the beginning of that section or chapter in the WEB The command can also be entered with a numeric argument prefix which some experienced Emacs users may wish to use If the change file has an entry for the destination section a message is printed in the minibuffer stating that the destination section has been edited The user can also goto the next or previous section or chapter by entering the commands M x web next section M x web previous section M x web next chapter M x web previous chapter If there is no next or previous section or chapter an appropriate message is displayed in the minibuffer otherwise
11. e command M x web view chapter titles list collects the names of the chapters along with their section numbers and displays them in another buffer The user is switched over to this buffer The result of issuing this command on Knuth s primes web is shown in Figure 4 Chapter Chapter Title 1 Printing primes An example of web 2 Plan of the program 3 The output phase 4 Generating the primes 5 The inner loop 6 Index Emacs Chapter Titles Web Al11 Figure 4 Chapter titles for Knuth s primes web While viewing this list the user can issue the command C c g s and respond with the number of the chapter indicated above The C c n s and C c p s commands are quite handy for moving to the next and previous chapters too 11 Support for Change Files Web mode also provides support for change files The command M x web view edited sections list C c ve can be invoked in either the buffer containing the WEB document or the buffer con taining the change file It displays in a separate window a list of the numbers of sections that have been edited The command M x web edit section C ces will insert the contents of the section that point is positioned in when the command is invoked in the change file in its proper position The entire section s contents are copied twice once between x y and once between y z The user is positioned at the first line after the y Thi
12. e command to place the point of the desired buffer file The user enters an f to find that file The user may wish to execute the command C x 1 to return to a single window If you know Emacs you know that several other buffers will be visible as well The information kept for using the index of variables and index of section names are buffers too Inserting a Section Name Whenever the lt key is pressed in the buffer containing the WEB document the function web insert section name is invoked This function must determine whether this is the beginning of a section name or not The function examines the preceding characters If an odd number of s immediately precede the lt then it is the beginning of a section name and web mode will automatically invoke the function web options for section name insertion otherwise the lt is inserted as the user continues typing If the function determines that it is the beginning of a section name the user is switched to a buffer with contents like those shown in Figure 1 The user must then select one of the options given Figure 1 is based on primes web a n example in 1 Option Action Abort Create a New Section Name A C L List all Section Names Beginning with Letter N Next Screen P Previous Screen S Select Existing Section Name Name for use with Selection based upon completion Fill table p with the first m prime numbers Give to j_prime the meaning j is a
13. eb next define C c nd M x web next use C c nu M x web previous define C c pd M x web previous use C c pu can be invoked from the buffer where the section names are displayed or they can be invoked from the buffer containing the WEB document If they are invoked from the former the user selects a section name by positioning the point anywhere on the line s where the section name of interest is located Once a section name has been selected the user is switched back to the buffer containing the WEB document Fill table p with the first m prime numbers 11 3 Give to j_prime the meaning j is a prime number 22 14 If p n is a factor of j set j_prime false 26 22 Increase j until it is the next prime number 14 11 Initialize the data structures 16 18 11 Other constants of the program 5 19 2 Output a line of answers 10 9 Output a page of answers 9 8 Print table Ipl 8 3 Print the first m prime numbers 3 2 Program to print the first thousand prime numbers 2 1 Update variables that depend on j 20 14 Update variables that depend on lord 21 25 20 Variables of the program 4 7 12 15 17 23 24 2 Emacs Section Name Defined In Used In Web Al1 Figure 3 Section names list for Knuth s primes web at the section where the most recently selected section name was next previously defined or used whichever is appropriate from point s current po
14. ep e 9 file web If there is not one of the index entry beginnings without an ending then you should probably email the file to bart cs tamu edu or some other willing fool Hopefully the experience of finding the answer will make it to this list Thanks to Marcus Speh for starting such thoughts 26 Appendix G Glossary buffer A buffer is the basic editing unit In Emacs a user can have many buffers however only one can be edited at any one time change file This file contains information that is used to override portions of the WEB file Each change consists of repeating the lines from the WEB file that require modification and the new lines that are to replace the old ones The TANGLE and WEAVE processors have the ability to scan both the WEB and change files so that the new lines replace the old lines at the appropriate places in the resulting high level language and TRX codes chapter We use chapter to mean a collection of sections A chapter is begun by the character pair chapter title The string of characters following the until the first period followed by white space space tab new line The chapter title is presented in a bold font in the section and in the default font in the table of contents include file Some WEB systems allow the inclusion of code through the use of i commands This is normally used in a slightly different manner than the C header files limbo file A
15. g the C hv iteration should quickly lead you to the offending item Sometimes it is just a stray 2 Let us hear from you 24 Appendix E Some Elementary emacs This will be a brief discussion of the really necessary things and a few sugges tions as to what goes in the file emacs Some of these may not be in exactly same order as in the file This was recommended by somebody just do it setq text mode hook turn on auto fill These lines make the invocation of web mode automatic if the name of the file ends with web The second line contains the name of the file where the byte compiled form of web mode el is on your system setq auto mode alist cons web web mode auto mode alist 3 the next line also allows w extensions setq auto mode alist cons w web mode auto mode alist autoload web mode usr local lib web web mode elc Major mode for editing WEB based documents t The next several show suggestions for the location of the weaves setq web call program cweave usr local bin cweave setq web call program fweave usr local bin fweave setq web call program weave usr local bin weave The location of the default limbo material file is shown Individual users may create and use personalized limbo files by editing this line in emacs setq web limbo material location usr local lib web limbo material These lines are included for users who don t like our
16. he first item came about from personal experiences of Bart Childs helping such users There used to be more in this list but they have disappeared due to improvements in web mode The users are requested to send in more 1 Watching the minibuffer gives you an idea as to what web mode is doing as it builds its pointers and lists It is not uncommon for WEBs written without web mode to have problems when used with web mode for the first time In at least one case it is still not obvious as to why we had the problem The solution of this case might be a help to other users The starting of web mode was nearing an end because it gave a message about collecting web index entries Then the terrible message File mode specification error wrong type argument stringp nil which seemed totally uncalled for A method of solution If the WEB has a good number of user supplied index entries then you can find a pretty good bracket of the error easily This is done by issuing the emacs command C hv Emacs will prompt for the name of the elisp variable you want described The answer is web index entries list and the last entry in it will be the last one processed If all entries are entered only once then the error will have happened between the point of the last entry in the list and the next entry that should have been added I suggest adding a lot of entries like BC 1 CB gt BC 2 CB gt say after each paragraph Repeatin
17. in the WEB document that is currently being edited The command M x web delimiter match check C c dm looks at the entire WEB document section by section It determines if the delimiters surrounding section names namely lt and gt are matched If the delimiters do not match properly a descriptive message is printed in a temporary buffer Web mode also makes it easier to enter index entries When the function M x web insert index entry C c i i is issued the user is prompted for two things 1 The type of font to be used Roman typewriter or user defined This deter mines the opening delimiter to the index entry either or and 2 The text of the index entry The complete index entry is then placed on a new line The command M x web rename section C c rs allows the user to rename a section Point should be positioned on the name that the user wishes to rename The user is prompted for the new name The user is then given the option of renaming a single occurrence all occurrences or is queried if each of the remaining occurrences should be renamed There are several functions in web mode that are invoked automatically when ever a particular key is pressed These functions include web AT sign processing which is invoked whenever the key is pressed The function checks to see if the is at the beginning of a line If it is the next character is read If this next character is either a space newline tab or as
18. ing vol 10 no 2 1989 pp 107 112 Norman Ramsey Literate Programming Weaving a Language Independent WEB Communications of the ACM vol 32 no 9 Sep 1989 pp 1051 1055 E W Sewell How to MANGLE Your Software The WEB System for Modula 2 TUGboat vol 8 no 2 Jul 1987 pp 118 122 E W Sewell Weaving a Program Literate Programming in WEB New York NY Van Nostrand Reinhold 1989 Richard M Stallman EMACS The Extensible Customizable Self Docu menting Display Editor in Interactive Programming Environments David R Barstow Howard E Shroke and Erik Sandewall Eds New York NY McGraw Hill Book Co 1984 pp 300 325 Harold Thimbleby Experiences of Literate Programming using cweb a variant of Knuth s WEB The Computer Journal vol 29 no 3 Jun 1986 pp 201 211 Sho Huan Tung A Structured Method for Literate Programming Struc tured Programming vol 10 no 2 1989 pp 113 120 Christopher J Van Wyk Literate Programming An Assessment Commu nications of the ACM vol 33 no 3 Mar 1990 pp 361 and 365 18 Appendix A Assorted Information and Tables With the exception of the function web mode save buffers kill emacs all keybindings have a similar form that consists of three parts Each command is prefaced with C c The rest of the keybinding is the first letter of two following words in the function name Alphabetized Listing of Web mode Comm
19. o material are inserted The user is prompted for the title of the WEB This is not intended to be the name of the file but a better name like say the title of a book about the program being written The command invoking the editor showed an assumption that we feel should be honored We recommend that the names of WEB s end with web We also allow the use of the extension w because that is how CWEB is distributed We also recommend that included files assuming you are using i commands available in CWEBand FWEB not end in web We recommend endings like hweb It just seems more literate Editing a WEB Created Without web mode If you wish to use web mode on an existing WEB say primes web you would begin by invoking Emacs with the UNIX command emacs primes web When the function web mode is executed it will perform some initialization of various data structures A list of the section names is collected If web mode detects that a section name has been used but never defined a stub section is inserted at the end of the chapter in which it was first used A stub section is like O Stube gt lt Name of undefined section gt Web mode also reads the CHange file that accompanies the WEB currently being edited If there is no CHange file one is created however this file is saved only if it is modified The WEB Is Like A Book The user should understand that we are using a book model for a WEB The b
20. ocess The first argument to this function is the name of the program that is to be run as a separate process If the program names of the WEAVE pro cessors differ on your system elisp variables need to be reset accordingly in the file emacs At Texas A amp M we have modified WEAVE so that it writes the index to the file jobname idx and the list of section names to the file jobname scn The changes that must be made to WEAVE to accomplish this are contained in Appendix C Bertrand Joseph postulate 21 boolean 15 CTs cc 5 7 8 10 Dijkstra Edsger 1 15 Eratosthenes sieve of 24 false 13 26 integer 4 7 12 17 24 je 12 j prime 13 14 15 22 26 k 12 Knuth Donald E 15 m 2 mult 24 25 26 n 23 new_line 6 9 10 new_page 6 9 ord 17 18 19 20 21 22 23 24 25 ord_max 17 19 23 24 output 2 6 output format 5 9 p 4 Emacs INDEX for primes web Web Top Figure 2 Index for Knuth s primes web Viewing the Section Names The user can also view the contents of the list of section names that is main tained by web mode When the command M x web view section names list C c vs is issued the list is displayed in another buffer Some reformatting is necessary The user is free to peruse the list as much as he likes The results of issuing this command on Knuth s primes web is shown in Figure 3 The commands M x w
21. point moves to the beginning of the next or previous section or chapter appropriately The user can determine the section or chapter number that point is positioned within by the commands M x web which section C c ws M x web which chapter C c we Movement Among the Buffers Several commands facilitate movement within the WEB document The user can switch to the buffer containing the CHange file by issuing the command M x web goto buffer change file Similarly the user can switch to the buffer containing the WEB file at any time with the command M x web goto buffer web file If the WEB being edited is a CWEB the user can switch to any of the include files with the command M x web goto buffer include file This command takes a numeric argument For example giving the function an argument of 1 would cause the buffer containing the contents of the first include file command i encountered in the CWEB to become the current buffer Unfortunately web mode can be confusing as to which buffer you want In particular if there are multiple includes how does one know which one to go to Fortunately a solution is provided via the command M x buffer menu When invoked this command opens a window containing a list comprised of the following files the WEB file the CHange file and the include files The user types the command C x o to change the point to the window with the list of files Then the user uses the next and previous lin
22. r show all C csa Move By outline next visible heading C cnh Visible Heading outline previous visible heading C cph outline forward same level C c f 1 outline backward same level C c bl outline up heading C cuh Entry hide entry C che Actions Subtree hide subtree C chs show children C csc hide leaves C c h 1 show branches C c s b Movement at the Same Level Miscellaneous Outlining These commands need to be reworked to agree with the web prefix and to ensure a little more consistency 21 Appendix B Basic Information Like Variables etc Previous versions of this manual included a list of global variables The reason for this list is to help debugging in case of errors This is cumbersome to try to keep updated as we begin to have more users and contributors to the evolution of this package We have replaced this by some instructions as to how to generate a current list and how that is used The list of global variables is easily generated by finding all lines with the string defvar on them Using grep this is simply grep defvar web mode el gt DefVar On UNIX like systems the file DefVar will contain the list of variables with a little more information The documentation for the above can be viewed by issuing the command M x describe variable At the prompt the name of the variable of interest should be entered The response will be the help text entered when the variable was declared and its current
23. s command is only available in the buffer containing the WEB document The command M x web which edited section C c we can only be invoked in the buffer containing the change file This function displays a descriptive message informing the user of what section in the WEB the change that point is positioned in corresponds to Movement within the change file is accomplished with the commands M x web goto edited section C c ge The user is prompted for a numeric argument Point is then positioned at the beginning of the change in the change buffer that corresponds to the section number given as an argument M x web next edited section C c ne This command positions point at the beginning of the next change in the change buffer M x web previous edited section C c pe This command positions point at the beginning of the previous change in the change buffer The command M x web count edited sections C c e will display the number of sections that have been edited 12 Outline Mode An outline mode has been included based on other Emacs modes The changes necessary were to decide what the strings are that define the various levels for the outline These operations hide all information execpt the headings and then reverse the operation This applies to the entire buffer M x hide body C c hb M x show all C c sa Once you have put the buffer into outline mode you can navigate in the buffer based on these headings M x outline next
24. sition While in the WEB document the Defined In and Used In lists can be tra versed with the commands M x web next define C c nd which positions point at the beginning of the section where the most recently se lected section name was next defined M x web previous define C c pd which positions point at the beginning of the section where the most recently se lected section name was previously defined M x web next use C c nu which positions point at the beginning of the section where the most recently se lected section name was next used and M x web previous use C c pu which positions point at the beginning of the section where the most recently se lected section name was previously used It should be noted that these commands prevent the user from running off either end of either list Web mode maintains a list of the form section name 1 Defined In Sections Used In Sections section name 2 Defined In Sections Used In Sections section name n Defined In Sections Used In Sections This list is collected automatically by web mode and dynamically maintained If the user feels that this list is in error at any time during an editing session the list 10 can be recollected with the command M x web collect section names Viewing the Chapter Titles The user can also view a list of the titles of the chapters in the WEB document and the section number where each chapter begins Th
25. sub_1 hweb and sub_2 hweb After entering the statement i sub_1 hweb we suggest that you C xC f and respond with the sub_1 hweb Enter one blank line and C xb followed by an enter and you will be back into the WEB file Entering M x web mode reset will ensure that you can now communicate among the files in the preferred manner This same process is repeated to create the other included file Of course if they already existed then you did not need to visit them to create them Again we consider it slightly illiterate if these files have an extension of web Try it out on NewtonC web NewtonF web PS_Quasi web and the sources of the different WEB systems This page and 3 should be a bit longer or another document of examples should exist 16 A Final Note Any suggestions for enhancements problems with the existing functions or criticisms can be submitted to e Bart Childs bart cs tamu edu Mark Motl is not available through the networks at this time The use of the pronoun I obviously should be we References 1 Donald E Knuth Literate Programming The Computer Journal vol 27 no 2 May 1984 pp 97 111 2 Bill Lewis Dan LaLiberte and the GNU Manual Group The GNU Emacs Lisp Reference Manual Emacs Version 18 for UNIX Users Edition 1 01 Cambridge MA Free Software Foundation Apr 1990 3 Richard Stallman GNU Emacs Manual Fifth Edition Version 18 for UNIX Users Cambridge MA Free Software Fo
26. terisk then the in combination with the next character constitutes the beginning of a new section 14 Another useful function that is invoked automatically is web newline which is invoked whenever the newline character is pressed This function positions point so that the next line has the same indentation as the current line that is being terminated One keybinding that Emacs users are familiar with has been rebound to an other function The keybinding C x C c has been bound to the web mode function M x web mode save buffers kill emacs Before this function makes a call to Emacs save buffers kill emacs it com pletes the journal file that is maintained by web mode This journal file keeps track of what file is being edited who is editing it when the editing began when the editing stopped and a count of the number of times each of web mode s interactive functions were used By default web mode maintains a journal file This file contains the user s name the name of the file being edited the start and stop times of the editing session total time in web mode and a count of each of the interactive web mode functions invoked during the editing session The collection of this file is governed by the Boolean variable web journal on which is set to t true This can be turned off by changing a line in emacs to setq web journal on nil 15 An Example Let s assume that you are creating main web which will input files
27. termination of whether a stub section needs to be appended is made and the new section name is added to the list of section names L This causes all section names that begin with a particular letter to be displayed The user is prompted for the letter If no section names begin with the desired letter an appropriate message is displayed in the minibuffer N This causes the next screen of section names to be displayed For example if the screen is capable of displaying 21 section names and currently section names 1 through 21 are displayed choosing N would cause section names 22 through 42 to be displayed P This causes the previous screen of section names to be displayed For example if the screen is capable of displaying 21 section names and currently section names 30 through 50 are displayed choosing P would cause section names 9 through 29 to be displayed S This option has changed from previous versions It now expects to do selection by a completion scheme that is popular with Emacs users The L N and P options can be helpful It is not required that the name being selected is visible on the screen Previous versions were based upon the number within a list This might seem like a severe interruption of the coding process However getting the named sections spelled and spaced correctly is critical Viewing the Index Section Names and Chapter Titles Web mode allows a programmer to view the index as created by WEAV
28. undation Oct 1986 Supplementary Sources 1 Adrian Avenarius and Siegfried Oppermann FWEB A Literate Program ming System for Fortran8x SIGPLAN Notices vol 25 no 1 Jan 1990 pp 52 58 2 Jon Bentley Programming Pearls Literate Programming Communica tions of the ACM vol 29 no 5 May 1986 pp 364 369 3 Jon Bentley and David Gries Programming Pearls Abstract Data Types Communications of the ACM vol 30 no 4 Apr 1987 pp 284 290 4 Jon Bentley Donald E Knuth and Doug Mcllroy Programming Pearls A Literate Program Communications of the ACM vol 29 no 6 Jun 1986 pp 471 483 5 Marcus E Brown An Interactive Environment for Literate Programming Ph D Dissertation Dept of Computer Science Texas A amp M University Col lege Station TX Aug 1988 6 Marcus E Brown and Bart Childs An Interactive Environment for Literate Programming Structured Programming vol 11 no 1 Jan 1990 pp 11 25 7 Peter J Denning Announcing Literate Programming Communications of the ACM vol 30 no 7 Jul 1987 p 593 8 Klaus Guntermann and Joachim Schrod WEB Adapted to C TUGboat vol 7 no 3 Oct 1986 pp 134 137 9 Eric Hamilton Literate Programming Expanding Generalized Regular Ex pressions Communications of the ACM vol 31 no 12 Dec 1988 pp 1376 1385 17 10 11 12 13 14 15 16 17 18 19 20
29. visible heading C c nh M x outline previous visible heading C c ph The outline form can have headings at several levels visible These commands allow you to navigate based upon traveling at the same level of heading skips subheadings and to move from a subheading to a higher level M x outline forward same level C c fl M x outline backward same level C c bl M x outline up heading C c uh The immediately following body part can be made invisible or visible with these commands M x hide entry M x show entry The user can make parts of the body and subheadings invisible or visible with these commands M x hide subtree C c hs M x show subtree C c ss The user can show children thereby making direct subheadings visible It does not affect the visibility of the body or subheadings two 2 or more levels down This command may be preceeded with a C u N command to furnish an argument If omitted the value of one 1 is used M x show children C c sc To make the body under heading and under its subheadings invisible while the subheadings remain visible M x hide leaves C c hl To make all subheadings at all levels visible M x show branches C c s b 13 Miscellaneous Functions The function M x web count sections C c s displays in the minibuffer the total number of sections in the WEB document that is currently being edited The function M x web count chapters C c c displays in the minibuffer the total number of chapters
30. ways We find them to be convenient and recommend they be commented or just left out of your emacs file setq web journal on t setq web i do not want to see section names t setq web i do not want stubs t 25 Appendix F Frequently Asked Questions FAQ Q How do I get started A After the bye statement in the source of this document is three files The first is emacs and it should be installed in the user s root directory There is some obvious editing that should be done to that file based upon the location of a few things You should also put limbo sty limbo material and byte compile and put web mode el and web mode elc in appropriate places Q If web mode is properly installed how do I get started A Simply issue the command emacs start web where the is an acknowledge ment that not all emacs invocations start the same The system will prompt you for acceptance of the use of the standard limbo material which you normally accept with ENTER You will then be prompted for a title This should be a few words say like a book title Go read the manual and code document and be literate Q What causes me to get a message like file mode specification error wrong type argument stringp nil A That probably happens from a messed up index entry Get out of the editor saving the web file and try these grep e file web grep e file web grep e 9 file web or the combination of all gr
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