Books on REXX REXX Manuals REXX Reference Book REXX Programming Book for TSO The Joy of   REXX     REXX Tutorial   The purpose of this tutorial is to get you started with REXX when there is no other way - you don’t have time to go to a class, don’t want to buy a complete book on it and try to find the things you need to know. This is nowhere near being complete. It just gets you going. For the complete story, contact me about courses in REXX. It’s just a taste of REXX. Start using it. Enjoy it. REXX is an interpreted language found in several environments, such as: Mainframe MVS or OS390 VM/CMS CICS DOS/VSE Midrange AS400 Other OS/2 Windows DOS It is a high level procedural language. It is on the same level as procedural languages such as COBOL, FORTRAN, PLI and C. It is a complete programming language and includes facilities for reading and writing files, although it is limited to the simplest file structure: ordinary sequential files. Its strength lies in its ability to do string manipulation, the simplicity of its logic structures and in the presence of many built-in functions that take the place of complex instructions. It is often used to execute operating system commands under the control of its logic. It is generally used without compilation, so this limits its execution speed; however this will be offset by the speed of development. This short paper will talk about the following REXX features of REXX on TSO and CMS: The initial comment SAY to display on the terminal The variable PULL to accept input from the terminal DO for looping EXIT to end your program Passing commands to TSO or CMS For the rest, you can refer to my new REXX Reference book, available from MVS Training (800) 356 9093 or http://www.mvs-training.com. Go to my web page: http://theamericanprogrammer.com. You’ll find information there about REXX, my REXX Reference book, other REXX books that you can order from Amazon.com, downloads and tutorials, setting up to execute REXX, REXX under DOS/VSE, REXX on the AS/400. Table of Contents     Setting up to execute a REXX program under TSO/ISPF. 4 Setting up to execute a REXX program under VM/CMS. 5 The Initial Comment 6 SAY - Display on the Terminal 7 Variables 8 PULL - accept input from the terminal 9 DO for looping 10 EXIT to End Your Program 11 Passing Commands to TSO 12 Passing Commands to CMS 13                 Setting up to execute a REXX program under TSO/ISPF. Create a library or PDS using ISPF option 3.2. Name: Its name should end in the type qualifier EXEC, although this is not a requirement. Example: ‘userid.REXX.EXEC’ Attributes: The library should be defined as 80 character record length, record format FB unless your company has other requirements. Using the ISPF Editor (option 2) create a member in your REXX library name it, as an example TESTREXX type in a short program in REXX, The following is an example: /* REXX TESTREXX */ SAY "HELLO THIS IS A REXX PROGRAM" Type SAVE on the command line. Make TSO aware of your REXX library. Type this on the command line: TSO ALTLIB ACTIVATE APPL(EXEC) DA(‘userid.REXX.EXEC’) You will need to do this once every time you log on to TSO and once after you do a "split screen", in the new screen. Execute your program Type this on the command line of any ISPF panel, including the editor: TSO %TESTREXX or whatever other member name you used in your REXX library. The program should execute. If three asterisks appear on the screen, press ENTER to clear them. More Information You can obtain more information about setting up to execute REXX on TSO at this Web address: http://theamericanprogrammer.com/programming/rexxsetp.shtml Setting up to execute a REXX program under VM/CMS. Using XEDIT create a file to that will contain your program. It will be on your "A" or primary read/write disk. Name: a two part name. the first part is up to you, use TESTREXX as an example the second part must be EXEC Type this from the READY prompt of CMS or on the command line of the FILELIST (or many other panels) XEDIT TESTREXX EXEC Type in your program, for example: /* REXX */ SAY "HELLO" An initial comment is required to distinguish REXX. From :EXEC and EXEC2. Type SAVE on the command line of the editor. You do not need to leave the editor now. To execute the program, type CMS TESTREXX on the command line while in the editor. type TESTREXX at the ready prompt         The Initial Comment For REXX to work in all environments start your program with a REXX comment. The minimum comment required is /* REXX */ starting in column 1 of the first physical line of your program. Other words are allowed inside the comment as well. The ending delimiter, */, may be placed on a different line from the first. Simplest example: /* REXX */ SAY "HELLO" Example with longer comment: /* REXX program "TESTREXX" to illustrate whether REXX works or not */ SAY "HELLO"   SAY - Display on the Terminal REXX is above all simple. The way to display information on the terminal is with the SAY verb. Anything after the word SAY on the same line will be displayed. Displaying a literal character string, or constant: SAY "HELLO THERE" Arithmetic: SAY 1 + 1 REXX will gladly do arithmetic on the SAY. Just don’t put the arithmetic operation in quotations! Variables: (The next section will describe variables.) NAME = "SUE" SAY NAME   Variables REXX makes using variables easy. There is no variable declaration or definition. Consequently there is no datatyping: all REXX variables may contain all types of data. You first use a variable by assigning it a value. Assigning a literal value: NAME = "SUE" Assigning another variable: FIRST_NAME = NAME Doing arithmetic: TOTAL = 1 + 1 For REXX to see and interpret a variable, revealing what is contained in the variable, the variable must not be in quotations: SAY NAME PULL - accept input from the terminal   Use PULL with a variable to read in something you type at the terminal. You should place a SAY before the PULL so the user knows what to type in. SAY "PLEASE TYPE IN YOUR NAME" PULL NAME PULL will convert to upper case. DO for looping DO allows you to repeat an instruction or several instructions. It can be used to initialize and increment a variable, and continue the loop until the variable is incremented to a certain value. This is equivalent to BASIC’s FOR loop, COBOL’s PERFORM, and most other languages’ DO. This example will initialize the variable INDEX to 1, increment it by 1 and continue looping until INDEX is greater than 10. While inside the loop it will display the variable I. Running this will produce the numbers 1 through 10. DO I = 1 TO 10 SAY I END EXIT to End Your Program The verb EXIT will end your program. It is not needed if it would be the last line in your program. It is needed if some other code, such as a subroutine follows the logical end of the program.   SAY "PLEASE TYPE IN YOUR NAME" PULL NAME SAY NAME DO I = 1 TO 10 SAY I END EXIT     Passing Commands to TSO For a discussion of TSO commands, get my paper TSOCMDS at: http://theamericanprogrammer.com/programming/justenuf.shtml To pass a TSO command to TSO, just place the TSO command first on a line, in quotations. Here is an example of a very simple TSO command: LISTCAT It will display a list of catalogued files whose name begins with your TSO userid. Placed inside of a REXX program it would look like: /* REXX */ "LISTCAT" The quotations around LISTCAT are optional in this case due to its simplicity. However you will normally put your TSO commands inside of quotations. This avoids having REXX try to interpret things it shouldn’t be interpreting. The next example will illustrate: /* REXX */ "SEND ‘HELLO’ USER(TSOUID2)" It is passing the TSO command SEND ‘HELLO’ USER(TSOUID2) to TSO. TSO understands this command; REXX doesn’t. To keep REXX from trying to understand you place it in quotations. Then REXX treats it as a literal and will not try to interpret it. It gets a bit more interesting when you have a variable in the TSO command and you do want REXX to interpret the variable. In this case, leave the variable out of the quotations but keep the rest inside. /* REXX */ USERID = "TSOUID2" "SEND ‘HELLO’ USER("USERID")" Although it is confusing to the eye, the variable USERID is outside of quotations and so REXX will see it and interpret it, changing it to its value (TSOUID2) and passing the entire line, as it sees it, to TSO. It will pass SEND ‘HELLO’ USER(TSOUID2) to TSO. Passing Commands to CMS   To pass a CMS command to CMS, just place the CMS command first on a line, in quotations. Here is an example of a very simple TSO command: ERASE JUNKDATA DATA A1 It will display a list of catalogued files whose name begins with your TSO userid. Placed inside of a REXX program it would look like: /* REXX */ "ERASE JUNKDATA DATA A1" The quotations around this command are optional in this case due to its simplicity. However you will normally put your CMS commands inside of quotations. This avoids having REXX try to interpret things it shouldn’t be interpreting. The next example will illustrate: /* REXX */ "MSG * HELLO" It is passing the CMS command MSG * HELLO to CMS. CMS understands this command; REXX doesn’t. To keep REXX from trying to understand you place it in quotations. Then REXX treats it as a literal and will not try to interpret it. It gets a bit more interesting when you have a variable in the CMS command and you do want REXX to interpret the variable. In this case, leave the variable out of the quotations but keep the rest inside. /* REXX */ MESSAGE = "HELLO" "MSG * " MESSAGE Although it is confusing to the eye, the variable MESSAGE is outside of quotations and so REXX will see it and interpret it, changing it to its value (HELLO) and passing the entire line, as it sees it, to CMS. It will pass MSG * HELLO to CMS.     About this series. Sometimes you need just enough information so that you can do something - it gets you started when you don’t have time to learn everything. Get all the others in the series at: Justenuf Other Books for professionals: REXX Reference All REXX verbs, keywords, and built-in functions as found in MVS, VM/CMS and OS/2. Order from MVS Training (800) 356 9093.MVS Training The REXX Language on TSO How to use REXX on TSO. Information, ordering at: REXX ISPF Services: Using the Dialogue Manager with REXX How to create ISPF panels on TSO. Examples in REXX. Information, ordering at:ISPF Services You will find a large selection of mainframe books at:Books. You’ll find manuals on TSO, JCL, REXX, COBOL, DB2 at:Manuals.   Top of Page

List of books on REXX and other mainframe topics