Developerworks overview of rpg free format the ibm i zone of developersworks contains many articles about best coding practices for ibm i as well as the latest technology for our platform. The additional freeform rpg support provides freeform programming for h, f, d and p specs and is intended to make rpg programming easier for both existing rpg programmers and to those trying to learn rpg. Profound logics alex roytman and liam allan are here to show you how free format rpg and node. Jul 26, 2005 as a registered member of, youre entitled to a complimentary copy of chapter 3 of free format rpg iv written by jim martin and published by mc press. There are a number of alternatives to the moverelated operation codes, and therein lies the challenge in converting to free format. For those of you who have not tried it yet, these are the rules for coding in free form. Simple define a procedure calling the api in this example i call it writejoblog and.
International technical support organization who knew you could do that with rpg iv. I thought about the varying thing but didnt realize you could use 2 keywords like that. In this example, im going to load an externally defined record format into a data structure thats based on a pointer. If factor 1 is not specified, the length of the string from the start position is used. Some of the more useful opcodes follow, but not all. From the earliest versions of rpg to the latest release of freeformat rpg iv on ibms eserver iseries now i5 platform, the changes have been dramatic. I would say its an excelent book available in the market on this subject. This book provides everything one needs to know to write rpg iv in the free format style, and author jim martin not only teaches rules and syntax but also explains how this new style of coding has the potential to improve overall programmer productivity. You can easily become more familiar with ile rpg also confusingly called rpg4, rpg5 or rpg free just by running older rpg source through ibms cvtrpgsrc command. Inputoutput using free format most input and output functions are the same in freeformat rpg iv as in fixed format except for the location of the code within the source line. One more substantial difference introduced in free format is the use of alternatives to a key list in database i0 for chain, set, and similar operations. Semicolon is necessary at the end of every free format statement. Freeformat rpg iv s rules for naming variables are no different from fixed format s, but when employing longer names more than 14 characters, you must use either the extended factor 2 format or free format in your calculations. This latest version includes the modern free format declarations and other recent language enhancements as well as covering essentials such as building and using service programs.
Plenty of coding examples illustrate the new free format calculation specifications, as well as the latest built in functions and other features of todays rpg iv. Traditional fixed format rpg programmers everywhere are embracing the increased productivity, better readability, and easier program maintenance that comes with the free format style of programming in rpg iv. On performing research for this post i found that with free format read operations a number of additional extenders were added, some are available with only some of the read operations in. Graphic illustration of rpg nesting in free format. So, i thought i could convert it to char ie, %charvarcharfld, the compiler says no. Is there a syntax issue, or do i just have to specify the position for these keywords. This book provides everything you need to know to write rpg iv in the free format style. Programming in rpg iv, third edition download free epub, pdf. Below example of %subst extract year, month, day etc. Free format rpg uses many of the same operation codes. So one either briefly resorts to fixed format calculations or one finds an alternative.
Focusing strictly on teaching free format rpg programming methods, this book will help programmers wishing to upgrade their skills this howto guide offers a concise and thorough introduction to the increased productivity, better readability, and easier program maintenance that comes with the free format style of programming in rpg iv. Refer to the essential guid to free format rpg by bryan meyers. But most people ask this question in the context of the eval opcode or the socalled free format rpg iv syntax. This tip reveals what to do for six of the lost operations. Ile rpg built in functions %abs absolute value of expression %addr get address of variable %alloc allocate storage %char convert to character data %check check characters %checkr check reverse %date convert to date %days number of days %dec convert to packed decimal format %dech convert to packed decimal format with half adjust. Functions in freeformat rpg iv by jim martin nook book. The author uses many examples that are easy to understand and practical.
We have been using the earlier versions of this book as part of our introduction to rpg iv classes for many years now. In order call an external program in free format, you need to use prototype for the external program. The rpg programming language has certainly come a long way since its introduction as a simple report program generator in the 1960s. Functions in freeformat rpg iv by jim martin 9781583470879. In free format the eval operation is not required sometimes. If the keyword extpgm is specified on the prototype, the call will be a dynamic external call. With subfiles in free format rpg, you will learn how to.
This article takes a look at the many aspects of free form rpg including many code examples. Free formats arrival caused little fanfare back then, and most rpg iv developers with whom. The case structure is used to control sections of the program. Rpg iv concepts as of v5r2 ic2924 at the ibm iseries information center. Movea 0000 in51 since movea is not acceptable using the free format i tried the. Also, you can use the plus operator for concatenation and the freeform if statement can. The format of the substring builtin function is shown in this example. Free form code is placed between the free and end free compiler directives. The join command is the opposite of subst, because join will take. Post by chris few issues im running into wvarchar and rpg. This book provides everything one needs to know to write rpg iv in the free format style, and author jim martin not only teaches rules and syntax but also explains how this new style of coding has the potential to improve overall programmer productivityfrom initial development through maintenance. This book provides everything you need to know to write rpg iv in the freeformat style.
The essential alternatives summarizes the alternatives. When specified on a freeform calculation specification, the parameters may be any expression. In the earlier flavors of free format rpg they could just switch from free format to fixed to do the call, and return to free format afterwards. As of v5r3, the %dec builtinfunction was offically put on steroids. Whereas most programming languages include a goto command, free format rpg does not. The structure of an operation is the operation code.
The alternative i prefer, and which i have used with great success, is. Ive been trying to convert a series of rpg iv programs to free format, but ive been. Im trying to use this function to mask out the first 5 digits in a social security number for my homework assignment. After that line, the entire source member must be freeformat. Free format rpg iv is the onestop resource that will save you time and frustration. Quick path to free 1 regardless of what conversion utility you plan to use, first run the jcrfreess free fixed sidebyside view command to show your original rpg4 fixed format code on the left and what that code will look like converted to free on the right. Please could you advise me on the best book available on converting my existing rpg 400 knowledge to rpg iv and ile. Introducing freeformat rpg iv the ability to create freeformat calculations in rpg iv became available with the arrival of version 5 release 1 of websphere development studio, ibms application development tool suite for the ibm i operating system. The book comes packaged with a 123type tutorial, lab exercises, and powerpoint presentations with notes on the slides that make for handy reference material immediately available on your workstation. Refer to the essential guid to free format rpg by bryan meyers the this article describes the issues involved in converted the move, movel and movea opcodes to free format.
Free your code convert fixed format code to free format, part 3. When name specifies a format name and the format name is associated with a multiple device file, data is read from the device identified by the field specified in the devid keyword in file specifications. Subst built in function in rpgle partially extracts the string from any position. Datagate for ibm i and datagate for sql server differences. Oct 22, 2003 this is the rpg programming on the as400 iseries rpg400l mailing list to post a message email. One more substantial difference introduced in free format is the use of alternatives to a key list in. Ill then use my pointer to put that data structure into the area of memory thats required to use it in a trigger program. Author jim martin not only teaches rules and syntax, but also explains. This book is a great book for beginners to intermediate programmer for text as well as for reference. Ile rpg builtinfunctions %abs absolute value of expression %addr get address of variable %alloc allocate storage %char convert to character data %check check characters %checkr check reverse %date convert to date %days number of days %dec convert to packed decimal format %dech convert to packed decimal format with half adjust.
Rpg iv and rpg ile book solutions experts exchange. Transform legacy rpg code to modern free format rpg and node. This book gives you the concepts, styles, and advanced techniques using free format rpg that will enable you to become a subfile master in your own right. The windows subst command is available in supported versions of the command line interpreter cmd. The last two techtips provided some insights about the process of converting rpg classic code to free format. In other words, if you write programs in freeformat rpg iv, you must use bifs to accomplish the needs of your programs. Inputoutput using free format most input and output functions are the same in free format rpg iv as in fixed format except for the location of the code within the source line. Modern rpg for the modern programmer december 2016 sg24540201. If you are new to free format rpg and deal with any kind of character or numeric date data, you have no doubt been frustrated trying to figure out how to convert data from one format to another. Or perhaps you are using date data types in newer databases and are still dealing with legacy date data types in some other format.
Free format and fixed format can be intermixed within the standard coding guidelines, of course. For free format always use the actual name of the file and not the record format name. My 4th edition programming in rpg iv book just briefly explains this which is. Movea using ile free format showing 17 of 7 messages. If the program requires fixedformat code, it must be in a copybook. Wally schwarz sent me pdfs containing scans of the forms for the file description, input specifications, calculation specifications, and output format specifications which can be printed and used to code the specifications for an rpg program. The this article describes the issues involved in converted the move, movel and movea opcodes to free format. For example, the subst opcode is now the %subst bif, in freeformat. Some free format examples only work with v5r1 and higher. Movea 0000 in 51 since movea is not acceptable using the free format i tried the. The alternative i prefer, and which i have used with great success, is to use a status variable. The first line of any source file that contains fullyfree code must contain the special free directive in column 1 of the first source line. Free form psds proc when im converting my program status data structure from fixed format to free form, i expect this to work, but it doesnt. Hi, im a rpg 400 programmer as400 and want to update my skills to include rpg iv and ile.
Rpgle free format call program example as400 iseries. The only call possible in free format is the prototype call, callp. Overall, however, most rpg programmers even the oldtimers have come to appreciate the virtues of free format. Each one provides a little bit extra functionality that compliments the read operation. I added the varying keyword and took out my %trimrowi statements and tada. His book the modern rpg language has been the most widely used rpg programming book for more than a decade. The second parameter for %replace and the first parameter for %subst have to be string. This chapter, inputoutput using free format, takes a look at the operations, options and built in functions now available for database io, as well as for workstation io and printer output. Aug 05, 2012 an rpg free template for subfile programs. At least one space must separate the pieces of the statement. Rpg code example write to joblog in rpg4 free with qp0zlprintf write to joblog lets us send messages from inside a running rpg program. The start parameter represents the starting position of the substring.
Prior to v5r3 all the function did was convert nonpacked numeric data to packed numeric format. The lookup opcode could be any of 10 bifs in freeformat rpg iv. So, if you are an experienced legacy rpg programmer but havent kept abreast with the huge changes to rpg over recent years, dont be put off. Write to joblog messages from rpgle free easy code example. If there is no such entry, data is read from the device used in the last successful input operation. In this webinar, youll learn how you can use both profound ui and profound. Nov 15, 2016 in order call an external program in free format, you need to use prototype for the external program. Two notes as400 index of links qas400 rpg ile rpgle clp.
Its simple using one of ibms apis qp0zlprintf ive used this little technique for ever. When specified on a freeform calculation specification, the parameters may be any. My first book, free format rpg iv mc press, 2005, addressed this situation. Calling a program in totally free rpg someone said to me that the reason that they will not use totally free rpg is they cannot call programs using it. Case offers greater readability than ifthenelse when a high level of nesting is required or when the control structure is controlling several dozen lines of code. Here 1st parameter is the source string from which we want to extract some part of string. In the never ending loop shown below, string is the variable containing the string value which needs leading characters, most commonly leading zeros, stripped from the value.
Simple tasks in rpg iv made simpler rpg programming. So, instead of checking any resulting indicator we simply use %eof to check if the end of file is reached. So then i tried the compiler option, cvtoptvarchar. Freeformat rpg uses many of the same operation codes as traditional fixedformat. U subst substring the subst operation returns a substring from factor 2, starting at the location specified in factor 2 for the length specified in factor 1, and places this substring in the result field. If length is not specified, the substring begins with start and. This one covers a topic often overlooked, but extremely important.
Prototype call can be dynamic call or a bound call. In it, youll find everything you need to know to write rpg iv in the free format style. Variable names must begin with a character and can be in any case. Learn more about free format and other ile rpg functions in the ile rpg in easy bytes series, one of several online selfstudy courses available at my programming in ile rpg 5th ed. Which option youll use depends upon the data types and sizes of the source field and the target field. Learn more about free format and other ile rpg functions in the ile rpg in easy bytes series, one of several online selfstudy courses available at my copy members are considered to be fixed format syntax, even if you code the copy statement in a free format block of code. The latest edition of this bestselling textbook has been fully revamped to cover the rpg iv language in version 5. This option allows you to write the calculation c specs of your program without following the rigid positioning requirements of a standard rpg program and, for that matter, without the c. To use the centertext procedure, a calling procedure. The essential guide to free format rpg factor 1, if there is one, follows the operation code. Frequently, you can simply substitute a function for an operation code, including the function in an expression. Rpgle free format call program example as400 iseries free format rpgle does not support call. In v5r1, ile rpg rpg iv was given a facelift with the addition of a free format coding option. Character, character, use evalevalr, with or without %subst.
One challenge when switching from fixed to free format rpg iv is the disappearance of many frequently used opcodes. The length parameter represents the length of the substring. How to right justify a alphanumeric field with leading zeroes. Look up to %lookup february 4, 2009 susan gantner the %lookup builtin function is more than just a simple replacement for the lookup operation code to allow use in free format logic.
Mastering subfiles is often the defining moment in an rpg programmers career. Free format nested code illustration the modern rpg. With the enhancements to the compiler, removing the requirement for free the cspec statement is not intrusive. Commonly used operations for character manipulation in fixed format are scan, subst, cat, move, movel, and movea. One challenge when switching from fixed to freeformat rpg iv is the. For example, the arithmetic operations add, sub, mult, div, and so on can substitute. The essential guide to freeformat rpg provide more flexible coding, greater function, and more enhancement potential than their corresponding operation codes.
Simple tasks in rpg iv made simpler details robert cozzi. The java class presented below depends upon itext to place the imagefile into a. Author jim martin not only teaches rules and syntax, but also explains how this new style of coding has the potential to improve. Typically free format code does not require a graphic illustrating the nesting levels since it can be written in an indented manner. Freeformat rpg uses many of the same operation codes as traditional fixed format.
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