JCSM Shareware Collection 1993 November

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SCHOONER Version 1.00 Shareware User's Manual DISCLAIMER AND WARRANTY the small print We have done the best to make this a great package, it may not be perfect for you. Test it out. If you like it then register your copy and pass on another copy. The program is provides "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 (and not Jonathan Cook) assume the entire cost of all necessary servicing, repair or correction. Jonathan Cook does not warrant that the function contained in the program will meet your requirements or that the operation of the program will be uninterrupted or error free. In no event will Jonathan Cook be liable to you for any damages including any lost profits, lost savings or other incidental or consequential damages arising out of the use or inability to use such program or for any claim by any other party. Note: Clipper(r), Dbase and Foxbase are registered names and/or trademarks of Computer Associates, Borland and Microsoft. Any other name references, expressed or implied, are registered names and/or trademarks of their respective developers/manufacturers. INTRODUCTION Schooner is a powerful, full featured database programming language similar to other Xbase languages. The Schooner development environment revolves around the powerful text editor. From this command center you can develop and control your application. You can write source code, create reports, create and modify database structures, manipulate data and execute your code... All from within the text editor. In addition, when errors are detected, they are displayed in a red box. Schooner then places the cursor on the line where the error was detected, even if the error occurred in a module other than the one you were editing. Command and function help are just a keypress away. All language documentation is on-line and available with the F1 help key. Getting Started. Schooner is very easy to use. Simply copy the Sch100.exe file to a subdirectory and change to that subdirectory. Decompress the Schooner files by typing: sch100.exe All of the files will decompress and you are ready to go. To begin Schooner type: Schooner and press ENTER. The Schooner editor will appear. While the editor appears simple, it will reveal a great deal with the F1 key. Press F1 and the help screen for the editor will appear. This screen details all of the commands available to the editor. You can cut and paste blocks of text, read and write files (and blocks) to and from disk, create and edit data files and even create report templates with the report writer. Press the F2 key from the editor help screen and a list of all of the commands and functions available to the language appear. Scroll through the list. A short description accompanies each command or function. Press ENTER on a highlighted line and the complete description for that command or function appears. Each description contains the command or function name, the syntax, the use, a parameter description, return values, a general description and an sample piece of code. Press ESC and you will back out of the help system the same way you went in. Viewing an Example An entire demo application is available for your viewing pleasure. Press F8 and enter the file name: DMDEMO.PRG and press ENTER. The program DMDEMO will appear on the screen. To experienced XBASE programmers the code will immediately look familiar. Use the arrow keys to scroll up and down. When you are done viewing the code, execute it. Press Alt-R Schooner assumes you want to run the code that is loaded into the editor. You will note that the file name has changed to DMDEMO.RUN. In the blink of an eye the code has been saved and converted into the RUN format for execution. In fact all programs (.prg) are automatically saved and converted to .run format whenever you press Alt-R (or CTRL-W). This assures that your .prg and .run are in synch at all times. Play with the demo. When done press ESC from the demo menu and you will return to the exact location in the editor at which you left when you pressed Alt-R. The various programs that make up the demo are an excellent example of Schooner code. As mentioned above, if you have experience in Dbase(r) Foxbase(r) or Clipper(r) you will recognize Schooner right away. Programming in Schooner Schooner is a language interpreter. All code that is written and run is interpreted line by line. Experience shows that interpreters are best for fast development but slower in execution of code. Compiled software is fast in execution, but slow in development. Schooner attempts to find a good compromise to this problem. Since Schooner is a function interpreter as opposed to a command interpreter, there is very little interpretation that actually takes place. Thus Schooner runs faster than other interpreters of a similar design. However, Schooner goes one step further. All Schooner code is Clipper(r) Summer '87 compiler compatible. That's right, you can compile Schooner code with Clipper(r). Schooner provides all of the advantages of an interpreted development environment and the speed of compiled applications. Unfortunately, due to licensing issues, we cannot sell you Clipper(r). We can however provide you with the Schooner library and full instructions on how to compile your applications. See the additional compiler documentation below. Writing your first program From a blank editor screen press F8 and enter a new program name. Call it 'TEST.prg' for this example and press ENTER. Type in the following lines of code. Press ENTER after each line. clearscrn() superbox(00,00,24,79,.T.,"",.f.) mvcount=0 do while mvcount<50 message('The counter is: '+alltrim(str(mvcount)),'OFF') mvcount=mvcount+1 enddo message('DONE!!!') quit When you are done press ALT-R. This will save and convert your code to .RUN format. Press ENTER to accept the program to run and watch it go... This little program simply displays a counter on the screen. But it does give you a good idea of how simple a Schooner program is to write and run. In order to understand the code better, press F1 then F2 and look up each command and function in the on-line help. Schooner Technical Specifications In a nutshell, Schooner has virtually all of the capabilities of Dbase III plus(r) and Clipper(r) Summer '87. In addition, Schooner supports a whole set of graphics functions not found in either of the above languages. System Specifications: IBM compatible computers with 640k bytes of RAM, hard drive, one floppy, DOS 5.0 (developed in 5.0 but should work in version 3.30 or higher) and a color monitor for graphics display. Field types: Character........32K Numeric..........Max 19 bytes Date.............8 bytes Logical..........1 byte Memo.............Max 64k Indexing: Schooner supports indexing with the .NTX extension. Arrays: Single dimensional arrays. Any data type. Arrays are declared with the PUBLIC command. Files: Database........... .dbf Memos.............. .dbt Labels............. .lbl Reports............ .frm Program modules.... .prg Run modules........ .run Procedures and Functions: Schooner handles procedures much the same way as Dbase III plus(r). Functions are handled as described in the on-line documentation. Functions can be included in lines of code like any compiled functions but they cannot pass parameters (this is done by declared public variables), contain nested Schooner defined functions or call other Schooner procedures. Work Areas: Schooner supports 9 open files (work areas) and index combinations but not to exceed the number of files declared to DOS. Each data file must reside in its own work area and can be accessed by alias name or the FSELECT() function. Public: All variables in Schooner are declared as public (available to all procedures and functions) either automatically when assigned (mvname='John') or with the PUBLIC command. All variable names start with the letters MV and can contain a maximum of 10 letters. Operations: Math: + addition - subtraction * multiplication / division % modulus ^ raised powers ** " " Order: Operations are solved from left to right. Parentheses are solved first Exponentiation are solved second Multiplication and division are third Addition and subtraction are last Relational: < less than > greater than = equal <> not equal <= less than or equal >= greater than or equal $ contained within == exactly equal Logicals: .and. .or. .not. Strings: + join two strings together - joins two strings together but trims any trailing spaces from the first. Passing DOS Variables to Schooner Applications: You can pass DOS information to Schooner by declaring a DOS variable with the SET command. Use the GETE() function within Schooner to get the environment variable from DOS. Be sure that the DOS variable you reference in the GETE() function is upper case. See GETE(). Memory Management You can manage the use of memory with the following standard CLIPPER DOS environment variable settings: Set CLIPPER=Vxxx;Rxxx;Fxxx;Sx 'V' controls memory (in kbytes) used for tracking memory variables. If not defined then 20% of available memory is used (upto 44k) for variables. Since only 22 bytes are used for each variable, you can provide more memory to the rest of the system by declaring only that which is really needed for variables to Schooner. 'R' controls the RAM used for index buffers (these are internal buffers and not those declared in your config.sys) and the SHELL() function. Unless you are going to SHELL() to DOS, set this to the minimum 16K. 'F' overrides the files setting in Config.sys (but cannot exceed it). This can be helpful in managing the number of open files Schooner can use. 'S' can help to control snow effects on older monitors. Set to 1 (one) will help eliminate snow. You do not need to declare the CLIPPER variable to DOS, Schooner will simply use the defaults. However, in tight memory environments it can help your applications manage memory better. Network Applications Schooner should be compatible with most local area networks that recognize the Clipper(r) method of record and file locking. However, we do not have a LAN of our own to test with and cannot guarantee networking compatibility. In general, writing applications for networks is pretty easy. Observe the following: Open 'shared', all files that reside on servers that will be shared. Open other files (especially those that reside on the node PC) as exclusive. All shared files must use record or file locking in order to lock the record or file for exclusive use by the requesting node. Only the locking node can modify the record or file. Others, however, can read the file. Be sure to unlock the record or file when done so others can access the record or file. Reference the NETERR() function when performing network activities. This can help you determine error conditions that might arise. It is recommended that you use record locking for virtually all network activities. This leaves the rest of the file open for other users to access and provides better speed as more users access the file. However, OPEN() the file exclusively for such activities as FZAP() which will delete and pack the whole file. Error Detection During Execution As mentioned above, errors are trapped at run time and displayed in a red box on the screen. Error messages are standard Clipper(r) derived messages with hooks to the development environment that point the Schooner editor back to the line of code that generated the error. This allows Schooner to load the file that contains the error and place the cursor on the line of code with the error. Error messages generally describe the error well. However, not all messages are easy to trace. For the most part, error messages will define the function, the internal (not Schooner) line of offending code and a description of the error. The function described in the error message will most likely be the Schooner named function, but it may be an internal function. If it is an internal function, don't panic. The error is probably in a Schooner command or variable declaration. Let Schooner point you to the line of Schooner code and fix the error. Though rare, some errors may generate a condition where Schooner cannot point you back to the line of code. These are generally database file errors that corrupt the file handles used by Schooner. This does not cause damage. It simply means you have to manually load the source code file and find the error yourself. Even more rare are those errors which dump you back to DOS. Again, they rarely cause damage, but you will need to restart Schooner. Make liberal use of the SETEXIT() function to allow you to break out of infinite loop conditions. In emergencies use the Alt-C command. This will kill almost any situation and return you to DOS. Simply restart Schooner to fix the problem. The following are some of the more common errors: Database Required: You attempted to access a non existant database. Lock Required: You tried to perform a function which required the file or record to be locked. Use the file exclusively or lock the file or record. Exclusive Required: Similar to above. Use the file exclusively. Field Numeric Overflow: You tried to write a number into a database field where the size of the number is larger than the field can handle. Index File Corrupted: You have a damaged index file. Reindex. Type Mismatch: You tried to join or work on two variables that are of a different type. Subscript Range: You tried to use an array element that does not exist. In rare situations this message may appear if you have unbalanced IF..ENDIF or DO WHILE..ENDDO constructs. Zero Divide: You tried to divide by 0. Run Error: Occurs when a SHELL() error condition arises. Open Errors: These can occur when an error arises during a file open attempt. A number is included with the error that describes the DOS error type. Refer to your DOS manual for a full description of the error type. Print Errors: Generally occur when the printer is off-line or out of paper. Undefined Identifier: You tried to use a variable that has not yet been defined. Use the PUBLIC command to define it or assign it a value. This can also occur when an IF or DO WHILE statement tries to evaluate an expression with an undefined variable (EVEN WHEN THE STATEMENT IS NESTED WITHIN A FALSE CONSTRUCT. This can occur because all IF and DO WHILE structures are evaluated in order to maintain the internal structure stacks). Not an Array: You tried to use an array element that does not exist. Missing External: Generally refers to misspellings in your code that refer to commands or functions. Internal Error: An ugly one. Could mean a corrupted index file. Disk Full: Just like it sounds. Multiple Error: Several errors have occurred at once. Another ugly one. You will probable get dumped back to DOS. Out of Memory: You have run out of memory. Try modifying the above listed memory management variables to open up some more memory. In particularly large applications, try running your code with the SCHOONRT runtime module rather than directly from the editor. This is a hassle, but opens up more memory. Compiling your Applications As mentioned before, Schooner is code compatible with the Clipper(r) Summer 87 compiler. While we cannot supply you with the compiler and Clipper(r) libraries, we can provide you with the Schooner specific libraries and instructions on how to easily compile your Schooner code. The tools you will need are: Schooner and your Schooner code. The Clipper(r) compiler The Clipper(r) and Extend libraries The Schooner library The Schooner Schgraph library (for graphics) The Microsoft(r) 'C' 5.00 LLibca library (for graphics) The Microsoft(r) 'C' 5.00 Graphics library (for graphics) You will note that for graphics applications you will need the additional 'C' libraries listed above. Unfortunately we cannot supply these for licensing reasons. If you already have the Clipper(r) tools described above and want to take advantage of Schooner functions (not commands), they can be directly intermixed with Clipper(r) commands and functions in your Clipper(r) applications. In addition, the Schooner graphics should be accessible (without recompiling with the Microsoft(r) libraries described above) by using one of the many third party memory overlay functions available. In theory (We stress theory as we have not done this ourselves), you should be able to overlay the SCHOONRT runtime module and use Schooner code to create graphics applications in your Clipper(r) applications. Note that the overlay technique described above is not the same as overlays commonly used by compilers and linkers. The overlay described above is just a sophisticated RUN (or Schooner SHELL() ) which unloads your application and allows another applications to run in its place. When complete, the overlayed application is removed and your original application is restored. To order the Schooner compiler package send a 39.95 check or money order made out to 'Jonathan Cook' to the address listed in the README.DOC file.