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TRILOGY - A Note Retrieval System B. J. Ball 3304 Glen Rose Dr. Austin, Texas 78731 This program was initially developed as an aid to authors who, during the preliminary stages of writing a book, may accumulate several hundred individual notes dealing with particular aspects of the general subject to be written about. During the actual writing phase, the question inevitably arises of locating, as quickly as possible, all notes dealing with the specific topics currently under consideration. If the notes are kept in a computer file with each note having a header indicating the kinds of things it deals with, the program will allow the rapid retrieval of all notes dealing with a specified Boolean combination of topics. Since the keywords used in the note headers are likely to be dependent on the particular project, and not easily characterized in advance, use of a standard data base program might be inconvenient. Also the fact that the notes may range in length from a paragraph or two to several pages would be a nuisance in a program requiring a fixed (or maximum) record length to be specified at the outset. Another obvious use for such a program as this is keeping track of business or personal correspondence. Since most letters fall into several different classifications, it is sometimes difficult to know exactly where a particular one was filed. More importantly, when all letters relating to one or more specified topics need to be collected together, it would be convenient to have a better procedure than an exhaustive search of all the likely places. Using TRILOGY, it would only be necessary to give each letter a header consisting of keywords describing its relevant categories, after which all letters having a given combination of keywords in their headers could easily be retrieved. The program requires an IBM PC or compatible with at least 128K available memory . A hard disk, while helpful, is by no means necessary. To use TRILOGY, one starts with a text file consisting of a collection of "notes"; each note must be immediately preceded by an "identifier", which is just a sequence of keywords suggesting the content of the note. In order for the program to recognize identifiers as opposed to the text of notes, it is required that each identifier be enclosed in distinctive symbols which are not used anywhere else. (The file also should not use a tilde (~) since the program uses this symbol as an "end-of-text" marker.) By changing a configuration file, the user may select the header markers to be used, choose the delimiters for separating keywords in headers, specify which symbols other than letters and numbers will be allowed in keywords and determine whether keywords will be automatically capitalized or allowed to contain lower case letters. Color monitor users may also choose the foreground, background and border colors desired. (In default mode, headers are to be enclosed in curly braces {...} and keywords in headers may be separated by spaces, commas, semicolons, or any other symbol not eligible to be part of a keyword. Also, in default mode, all letters in keywords, whether originally entered as capitals or lower case, are converted to capitals by the program; keywords may contain apostrophes, hyphens or the underline character (as a space substitute), but may not contain spaces. For color monitor users, the default settings are white text on a blue background. The accessory program, TRIL-SET, allows the creation of a configuration file with different default values from these.) It is very important that the program be told whether or not a color/graphics card is being used, since there is a machine-language subroutine for fast screen printing which uses this information, and which will hang up the machine if this data is wrong. If there is no configuration file available to the program, the default values listed above will be used, but you will first be asked whether you are using a color card. Keywords must contain at least four characters, but there is no formal limitation on the maximum length - only the first eighteen characters of each keyword will be printed in the keyword list, but all characters are relevant in a search. There is a limitation (160 characters) on the length of the total identifier for a note, however, in order to help detect the fairly common error of failing to put a closing } at the end of an identifier. (If this happens, the program will try to read all the rest of the that note as part of its identifier, probably exceeding the 160 character limit in the attempt, whereupon processing will cease, with the suggestion that the source file be checked for a missing `}'. Although exceeding the maximum header length is a "Fatal Error", in the sense that the program will not continue after encountering it, nothing that has been done up to this point will be lost.) Operation of the Program Given a Source file satisfying the conditions stated above, TRILOGY will create three additional files - an Identifiers file containing a list of all the note headers from the source file, a Keywords file containing an alphabetized list of all keywords appearing in the headers, and a Records file, containing the individual notes. These three files may then be used to isolate quickly all notes whose headers contain a specified combination of keywords. The retrieved notes may be displayed on the screen, printed out on the printer, deleted altogether, or sent to a file. If a note is sent to a file, it can then be edited (using a word processor, after exiting TRILOGY) and can later be replaced in the Records file from which it came. In fact, it is possible to replace any note with an arbitrary one contained on the default disk, and thus information can be added to or removed from a note at will. Provision is also made for "updating" an existing collection of Trilogy files; i.e., adding additional notes, headers and keywords from a new Source File. The TRILOGY program and the desired Source File must initially be accessible to the program but need not be on the default drive/directory; the Identifiers, Keywords and Records files, however, are always placed on the default drive when created by TRILOGY, and must be there when used. As usual, "filespec" denotes the filename, preceded by the drive identification if different from the default drive, and followed by the filename extension, if any is used. For convenience, the program adopts a single "generic" name for all files related to a given source file - if the original file is A:SOURCE.BAS, the generic name is "SOURCE" and the Identifiers, Keywords and Records files are automatically named SOURCE.ID, SOURCE.KW and SOURCE.REC. When the program starts, you are presented with an abbreviated menu, since there is not much you can do until some Trilogy files have been created. The creation process will take about one minute for every 10K bytes in the Source File - 5 minutes for a 50K file, 10 minutes for a 100K file, etc. (These times are considerably less with a hard disk and are approximately halved if a Ramdisk is used. The time may also vary considerably depending on the average length of the notes and other factors.) Once a set of Trilogy files has been created - or selected, if previously created - the menu is expanded and the "Active" files are listed at the bottom. You may now choose to have the keywords or the identifiers printed, on the screen or on the printer. And you may also now use the "Findnote" feature, which is the primary purpose of the program. In Findnote, you will first be asked to enter either a "Search String" or a "Direct Command" both of which require some explanation. A Search String is a Boolean combination of OR's and AND's of Keywords, with OR taking precedence over AND, contrary to the usual convention. The only construction recognized is (xxx OR xxx OR ...) AND (xxx OR xxx OR ...) AND ... AND ... ; here the xxx's represent keywords, of which at least one must be present. Parentheses are optional, and punctuation (except for symbols which are allowed in keywords) will be ignored. The Boolean operators "AND" and "OR" must be set off by spaces, but need not be capitalized. (The program will supply parentheses to enforce the prescribed logical form - e.g., an entry such as "(x AND y) OR z" will be changed to "x AND (y OR z)", not at all what was wanted; to search for the former combination, use "(x OR z) AND (y OR z)". It would, of course, be possible to include a complete Boolean parsing routine, so that all combinations would be directly recognized, but that seems to be more trouble than it is worth. Giving OR precedence over AND and using the simple parsing scheme indicated above appears to handle the majority of desired searches, and the remainder present the user with interesting logical problems. The Boolean operator NOT has not been implemented, simply because it seems unnecessary.) Rather than entering a Search String, you may choose to give a Direct Command, identifying the desired notes by their positions in the original file (which may be read from an Identifiers list printed out by the program). You may enter a list of note numbers, a range of numbers, or a combination of these and may optionally end the command with one of the letters D,P,F,X,R to have the notes immediately Displayed, Printed, Filed, Deleted or Replaced. Direct Commands must start with the symbol "#" to distinguish them from Search Strings. Examples of Direct Commands are : #2,5,7-10,23 P to print out notes 2,5,7,8,9,10,23 #6-8x to delete notes 6,7,8 #5d to display note 5 In a Direct Command, spaces are irrelevant and invalid entries (including any letter not at the end of the command) will be ignored. Numbers larger than the total number of notes will be replaced by that total number. (This gives an easy way to operate on all notes in the current file, by using in a direct command a number known to be larger than the number of notes present.) The letter suffix, if used, may be upper or lower case; if a Direct Command has no letter suffix, the specified notes will be treated just as if they had been discovered through a search. Entering a question mark at the "Enter Search String or Direct Command" prompt will call up a help screen, which briefly describes the formats for Search Strings and Direct Commands. It should perhaps be noted that sending a note to a disk file does not automatically delete that note from the active Trilogy files; the X suffix on a separate command is necessary to delete notes. Since there is no provision for recovering deleted notes, deletion should be done with care and only on backed-up files. The strength of this program is not in its handling of Direct Commands, since any database program can do things to records whose numbers are specified by the user, but in its ability to quickly find all notes of a specified kind, through a Search String entry. In the Findnote routine the program will locate those notes whose headers contain a specified combination of keywords. Normally an exact match with a keyword is required in any search, but this may be changed by the use of the wildcard symbol * : a search for MAN will not find MANKIND, but a search for MAN* will; similarly, *MAN would find HUMAN and *MAN* would find both HUMAN and MANKIND (as well as MISMANAGEMENT,...). If you have chosen to allow keywords to contain lower case letters, all searches will be case-sensitive; otherwise (with the default settings, for example) you may use mixed case freely in entering search strings, since all letters will automatically be converted to upper case. Once a search string has been entered, all notes whose headers contain the specified combination of keywords will be located in a very few seconds. The screen will be cleared and the Search String used by the program will be displayed, followed by the identifiers of the located notes. You now have the option of choosing a note and either displaying it on the screen, printing it out on the printer, sending it to a file, deleting it from the Active files or replacing it with a note from the default drive. (If a Direct Command had been entered without a letter suffix, the identifiers for the specified notes would have been listed as above, and the same options would be available.) It is possible to display, print, delete or file several of the listed notes as one operation, by entering the analog of a Direct Command. Here the "#" prefix indicates that the numbers of the notes in the original file are used, just as before; if a list or range of numbers is entered here without using the "#" prefix, the numbers will be interpreted as the positions of the notes in the list of located notes (the result of the previous search). Both note numbers appear on the screen, with the original file numbers in parentheses. If the # prefix is notused and a number is entered which is greater than the number of notes in the current list, no action is taken and you are asked to reenter your choice; otherwise the Direct Command rules apply, with numbers that are too large being replaced by the total number of notes in the active files. Also, with the # prefix, you are not limited to only those notes in the current list, but may enter an arbitrary Direct Command. Before printing any notes, you should make sure the paper is located with the printer's "top-of-form" at the top of a page; the program counts lines to avoid printing on perforations, but this does no good unless the printer knows where the top of the page is, and starts there. When a sequence of notes is being printed, new pages are begun only when necessary, not at the begining of each note. You will be asked at the start of each printout whether you wish to begin a new page with this note or sequence of notes. There are no error traps for an off-line printer, so to avoid a bomb-out, be sure the printer is ready when the program wants it. (You are always given an opportunity to check that the printer is ready, but if you make a mistake about this, you will have the fun of starting all over.) There are two reasons for the File option - you may wish to write a note to a disk file in order to correct or modify it and then replace it in its original Trilogy file, or you may wish to separate off a subgroup of notes from the original file into a separate reference file, perhaps to be used later as the Source File for another application of TRILOGY. The "modify and replace" procedure - saving a note, exiting TRILOGY, using a word processor on the offending note, then reloading TRILOGY and replacing the note - is obviously a rather cumbersome procedure. Including even simple editing facilities, however, would make the program unacceptably large. (A resident word processor like Sidekick, or any of several commercially available multi-tasking or memory-partitioning programs will greatly simplify the modify and replace process by making both TRILOGY and your word processing program immediately available.) It should be noted that the "R" option can be applied to only one note at a time. When this option is used, however, the replacement note can be a virtually arbitrary file, not necessarily one which was previously extracted from the current Trilogy files. The only restriction is that any file used as a replacement for a TRILOGY note must include a header in the appropriate form. As mentioned, you may create a subcollection of the original note collection by sending a sequence of notes to a single disk file. This may be done all at one time or, since saved notes are appended to the target file rather than overwriting it, notes may be added to the subcollection individually or in small groups, just by specifying the same file name for each them. If you have deleted a significant number of notes, you may wish to save all the remaining ones to use as a Source File for a later application of TRILOGY, since the deletion process does not automatically reduce the size of the Records file. When a note is deleted from the Active files by using the X command, all keywords which occur only in the header of the deleted note will be removed from the keyword list. Similarly, if the header of a replacement note is different from that of the original, the keyword list will be updated appropriately. It might be convenient not to make the entire Source File at once,and the Update facility was included to allow creation of large Trilogy files from a series of separately composed, smaller, source files. Only the currently Active files can be updated, and it should be borne in mind that the updating process adds all the notes from the "Update File" (i.e. the Source File for this operation) to the existing Trilogy files; therefore the Update File should contain only new information. Also, of course, the Update File must be in the same form as an original Source File - a sequence of notes each preceded by an identifier delimited by the chosen header markers. Whenever the program is waiting for input from you, you may return to the menu by pressing the Esc key. This might be useful if, for example, the program wants you to enter a filename and you have forgotten what's available and want to use Option 1 to find out, or if you simply change your mind and want to cancel the operation you've started. Most single- character entries do not require that the Enter key be pressed, but all multiple entries do; generally, pressing Enter alone when a multiple-character entry is expected will return you to the menu. Overall, error trapping is pretty good, but as mentioned earlier, there are no error traps for an off-line printer; these were originally included, but turned out to be so unreliable (on my machine, at least) that eliminating them entirely seemed best. (The problem was that the error would be trapped the first time it occurred, and possibly the second time, but not every time.) The arrays used in the program are dimensioned to allow a total of 500 notes, 1500 distinct keywords and 2000 records (corresponding to a Source File of about 500K). Search Strings are arbitrarily limited to one screen line (79 bytes), and to a maximum of 10 AND phrases, each containing at most 10 OR's. (The program will not allow you to exceed the specified limits, but no information will be lost by an idadvertent attempt to do so.) This program should be useful to anyone involved in research of almost any kind, since in any research, a great deal depends on having readily at hand a large variety of information on particular aspects of the subject. Often, perhaps usually, creating the original Source File is a natural part of the procedure, especially if a computer file is ordinarily used. Everything else is done automatically by the program.