Welcome to the IBM Rational PL/I community. Here you will find the latest technical and business information, and educational information about PL/I and related z/OS and AIX topics including IMS, CICS, and Rational Developer for System z.
Pl/I 4.5 added a new option to help you check the correctness of your code when it runs, and I will describe it in a future blog. But first I would like to write about some existing features (some new and some quite old) that can help you check the correctness of your code (and, yes, compile times checks of your code are even better, and I will also talk about them in a future blog). One of the newest features that can help you check the correctness of your code (and simultaneously document the code as well) is the ASSERT statement. We... [More]
The new INLIST built-in function has made it easy for you to simplify code that tests if a expression is in one of a list of values. But sometimes you may want to test if an expression is in a range of values, as in IF BIRTHYEAR >= 1980 & BIRTHYEAR <= 1999 THEN The new BETWEEN built-in function makes it easy for you to simplify such code. This function returns a bit(1) value indicating if the value of an expression is within the... [More]
There are many times when you may want to test if a value is equal (or not equal) to one of a set of values. You can do this easily with a SELECT statement or an IF statement as in the following code IF (EXPLAN.ACCESSTYPE = 'I ' | EXPLAN.ACCESSTYPE = 'N ' |... [More]
When you use INLIST rather than a long list of comparisons OR'ed together, your code is easier to read and understand, but it is also easier for the compiler to understand and hence to optimize. For example, for an invocation of INLIST such as inlist( x, 2, 3, 5, 7, 11, 13, 17, 19 ) if x is a FIXED BIN(31) variable, the compiler will generate a branch table to determine the result. And in general, if x is FIXED BIN(p,0) with p <= 31 or FIXED DEC(p,0) with p <= 9, if all the values to test are similarly nice constants,... [More]
While the ASSERT statement discussed in the previous post is relatively new to PL/I (since it was introduced only with the 4.3 release), there is another, much older statement than can be used in a similar fashion: the SELECT statement. In particular, if you code a SELECT statement without an OTHERWISE clause, if none of the WHEN clauses are true, then the ERROR condition will be raised with an ONCODE and error message indicating that no WHEN clause in the SELECT is true. For example, if you code... [More]
Enterprise PL/I for z/OS V5.1 documentation is refreshed to include the following enhancements: Language Reference Enhancements in usability: The compiler now flags unreachable ASSERT UNREACHABLE statements with a different message than it flags other unreachable statements. The compiler now expands in the AGGREGATE listing typed structures that are member of other structures. The attributes listing now shows the contents of the VALUE attribute for CHARACTER and BIT constants of length 256 or less and also for numeric... [More]
IBM PL/I compiler has released a new version on System z. The recent announcement of Enterprise PL/I V5.1 reinforces the continuing IBM commitment to the PL/I programming language on the z/OS platform. Specifically, V5.1 offers: Enablement of PL/I applications to handle big data requirements with 64-bit support Increase in programmer productivity and application modernization with XML enhancements Over 20 additional customer-requested enhancements, which include: Built-in function enhancements to improve programmer productivity Support for... [More]
This will be the second half of the break from writing about checking program correctness and writing instead about some new things we made available recently via PTFs. Thing 1: SQL allows the use of a null data: a date with a year, month, and day all equal to 1. PL/I now supports this via a new compiler option: Under the new NULLDATE compiler option, the VALIDDATE and REPATTERN built-in functions will accept the SQL null date as a valid date. For compatibility, NONULLDATE is the default. To use this null date in... [More]
I want to take a break from writing about checking program correctness and to write instead about some new things we made available recently via PTFs. Thing 1: we have added a new built-in function to provide an "unhex" capability. It is modeled after the base64decode8 etc. built-in functions, and in the Language Reference Manual, it would be described as HEXDECODE decodes a source buffer from hex into a target buffer. It returns a FIXED BIN(31) value that indicates the number of bytes that are written into the target buffer.... [More]
There is another new built-in function that also makes it easy to simplify your code: NULLENTRY. Previously to assign a null value to an entry variable, you had to use the UNSPEC pseudovariable, and to test if an entry variable was null, you had to use the UNSPEC built-in function. Moreover, you had no nice way to use INIT with an ENTRY variable. But now instead of writing UNSPEC( funcptr ) = ''B;... [More]
IBM has been quietly delivering a new release of the PL/I compiler every year since 1999 on System z. The recent announcement of Enterprise PL/I for z/OS continues to show IBM’s commitment to delivering a world class PL/I compiler on System z. Enterprise PL/I for z/OS V4.5 is enhanced to fully exploit the new z13 architecture. It uses the new Vector Facility to improve the performance of the code generated for the verify and search built-in functions and expands the use of the Decimal Floating Point Facility for fixed decimal... [More]
There are three, perhaps overlooked, new features of Enterprise that let you "compile out" code either
unconditionally or conditionally:
To cause the compiler to skip some code unconditionally, you could try to enclose it in comments. But this works
only if that code itself contains no comments. However, as of the 3.9 release, you can enclose code
in %DO SKIP; ... %END; , and then the compiler will unconditionally skip over the enclosed code.
To cause the compiler to skip over some code conditionally, you can enclose it in a... [More]
IBM PL/I compiler team dedicates to offer a better support for you. As several new PTFs have been delivered, IBM PL/I compiler has released a new edition of Enterprise PL/I for AIX V3.1 technical docs. Specifically, new updates including: Language Reference As the AIX compiler essentially matches the PL/I V4.4 z/OS compiler, this updated Language Reference book is identical to the PL/I for z/OS V4.4 book. Several new attributes, statements, built-in functions and built-in subroutines have been included, such as the ASSERT... [More]
Are you looking for PL/I documentation across different releases? Do you want to access PL/I documentation of both the HTML and PDF format? The PL/I library pages now provide the following types of PL/I documentation in one central location: Announcement letters PDF documentation HTML documentation URL Start visiting the following PL/I library pages: Enterprise PL/I documentation library PL/I for AIX documentation library PL/I for MVS & VM PL/I for VSE
Peter Elderon from the IBM compiler development team will be presenting on what's new in Enterprise PL/I for z/OS at SHARE in Anaheim, March 9 to 14. 15284: PL/I - What's New Register for SHARE in Anaheim today!