24
Tue, Dec
1 New Articles
  1. You are here:  
  2. Home
  3. Programming
  4. Programming - Other
  5. CL
  6. The CL Corner: Cut, Snip, Trim with TRMLFTCHR

The CL Corner: Cut, Snip, Trim with TRMLFTCHR

CL
Typography
  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times

By adding new keywords to the command, you can trim any leading character.

 

In the previous article, "Going Where No Substring (%SST) Operation Can Go," we saw what the Trim Left Characters (TRMLFTCHR) command can do through the use of pointers:

  • Trim any leading zeros from a character string of any length that contains a non-negative numeric value
  • Left-adjust the remaining value within the string
  • Pad the string with blanks to its declared length

Today, we will see what is required to use TRMLFTCHR to do the same thing with any given leading character of any character string.

 

First, we need to add two new parameters to the TRMLFTCHR command.

 

The first parameter specifies what leading character should be trimmed from the command's VAR variable value if it's encountered. We'll identify this parameter with the keyword TRMCHR (for Trim Character) and define a default value of '0'. This default value is selected for compatibility with earlier versions of the command.

 

The second parameter specifies what value should be used if the input VAR character string is entirely comprised of the character specified for the TRMCHR keyword. The TRMLFTCHR CPP previously was hardcoded such that, if all zeros were found in the VAR input character string, the returned result would be a single character '0' padded with blanks. This, while OK for decimal values, may not be appropriate for any arbitrary character string that the command might process. We'll identify this parameter with the keyword ALLTRMCHR and define a default value of *TRMCHR. Using this default value will indicate to the command CPP that a single occurrence of the TRMCHR value should be used for the returned character string when no significant characters are found while processing the VAR variable. That is, if we're trimming zeros, then return one zero; if we're trimming asterisks, then return one asterisk; if we're trimming blanks, then return one blank (admittedly, then padded with blanks so it might be hard to "see"). If the user specifies a non-default value for ALLTRMCHR, then a single occurrence of the specified character, blank padded, will be placed in the returned result.

 

The new command definition source is shown below.

 

Cmd        Prompt('Trim Left Characters')                

Parm       Kwd(Var) Type(*Char) Len(1) RtnVal(*Yes) +    

             Min(1) Vary(*Yes *Int4) +

             Prompt('Decimal value')  

Parm       Kwd(TrmChr) Type(*Char) Len(1) Dft(0) +       

             Prompt('Character to trim')                 

Parm       Kwd(AllTrmChr) Type(*Char) Len(1) +           

             Dft(*TrmChr) SpcVal((*TRMCHR X'FF')) +      

             Prompt('Character for all trimmed')         

 

The definition for the VAR parameter remains the same as with the previous definition. The TRMCHR parameter is defined as a character value with a length of 1, defaulting to the value of 0. The new ALLTRMCHR parameter is defined as a character value with a length of 1, defaulting to *TRMCHR. As the default value of *TRMCHR exceeds the length of the parameter, the SPCVAL (Special value) keyword is used to map the value *TRMCHR to the 1-byte character value x'FF'. The decision to use this value (x'FF') is somewhat—but not completely—arbitrary, with my rationale not being pertinent to this article other than it's unlikely that you will have character data containing a leading x'FF' value.

 

To create the new version of the TRMLFTCHR command, you can use the same CRTCMD command that was used in previous articles:

 

CRTCMD CMD(TRMLFTCHR) PGM(TRMLFTCHR) ALLOW(*IPGM *BPGM *IMOD *BMOD)

 

As we've added two new parameters to the command, we also need to update the TRMLFTCHR CPP. The updated version of the TRMLFTCHR program is shown below.

 

Pgm        Parm(&Char_Parm &TrmChr &All_TrmChr)              

Dcl        Var(&Char_Parm)  Type(*Char) Len(5)               

  Dcl        Var(&Char_Siz)   Type(*Int) Stg(*Defined) +     

               DefVar(&Char_Parm 1)                          

  Dcl        Var(&First_Char) Type(*Char) Len(1) +           

               Stg(*Defined)    DefVar(&Char_Parm 5)         

Dcl        Var(&TrmChr)     Type(*Char) Len(1)               

Dcl        Var(&All_TrmChr) Type(*Char) Len(1)               

                                                             

Dcl        Var(&Char_Ptr)   Type(*Ptr)                       

Dcl        Var(&Char)       Type(*Char) Len(1) +             

             Stg(*Based)    BasPtr(&Char_Ptr)                

                                                             

Dcl        Var(&CharTgtPtr) Type(*Ptr)                       

Dcl        Var(&Char_Tgt)   Type(*Char) Len(1) +             

             Stg(*Based)    BasPtr(&CharTgtPtr)              

                                                                     

Dcl        Var(&Char_Pos)   Type(*UInt)                              

Dcl        Var(&Char_Rem)   Type(*UInt)                              

Dcl        Var(&XFF)        Type(*Char) Len(1) Value(x'FF')          

                                                                     

ChgVar     Var(&Char_Ptr) Value(%addr(&First_Char))                   

ChgVar     Var(&CharTgtPtr) Value(%addr(&First_Char))                

                                                                     

DoFor      Var(&Char_Pos) From(1) To(&Char_Siz)                     

           If Cond(&Char *EQ &TrmChr) Then(Do)                      

              ChgVar Var(%ofs(&Char_Ptr)) Value(%ofs(&Char_Ptr) + 1)

              Iterate                                               

              EndDo                                                 

           Else Cmd(Leave)                                          

           EndDo                                                    

                                                                    

If         Cond(&Char_Pos *LE &Char_Siz) Then(Do)                   

           DoFor Var(&Char_Pos) From(&Char_Pos) To(&Char_Siz)       

                 ChgVar Var(&Char_Tgt) Value(&Char)                

                 ChgVar Var(%ofs(&CharTgtPtr)) +                   

                          Value(%ofs(&CharTgtPtr) + 1)             

                 ChgVar Var(%ofs(&Char_Ptr)) +                     

                          Value(%ofs(&Char_Ptr) + 1)               

                 EndDo                                             

                                                                    

           If Cond(&Char_Ptr *NE &CharTgtPtr) Then(Do)             

              ChgVar Var(&Char_Rem) +                              

                       Value(%ofs(&Char_Ptr) - %ofs(&CharTgtPtr))  

              DoFor Var(&Char_Pos) From(1) To(&Char_Rem)           

                    ChgVar Var(&Char_Tgt) Value(' ')               

                    ChgVar Var(%ofs(&CharTgtPtr)) +                

                             Value(%ofs(&CharTgtPtr) + 1)          

                    EndDo                                          

              EndDo                                                

           EndDo                                                   

                                                                  

Else       Cmd(Do)                                               

           If Cond(&All_TrmChr *EQ &XFF) Then( +                 

              ChgVar Var(&Char_Tgt) Value(&TrmChr))              

           Else Cmd( +                                           

              ChgVar Var(&Char_Tgt) Value(&All_TrmChr))          

           ChgVar Var(%ofs(&CharTgtPtr)) +                       

                    Value(%ofs(&CharTgtPtr) + 1)                  

           DoFor Var(&Char_Pos) From(2) To(&Char_Siz)            

                 ChgVar Var(&Char_Tgt) Value(' ')                

                 ChgVar Var(%ofs(&CharTgtPtr)) +                 

                          Value(%ofs(&CharTgtPtr) + 1)           

                 EndDo                                           

           EndDo                                                 

                                                                 

EndPgm                                                            

 

The changes needed for the TRMLFTCHR program are fairly minor:

 

  • Change the PGM PARM keyword to indicate that three parameters are now being passed. The parameters are passed in the same sequence as the PARM commands are found in the command definition.

 

                Parm(&Char_Parm)

 

                becomes

 

                Parm(&Char_Parm &TrmChr &All_TrmChr)

 

  • Declare the two new parameters.

 

                Dcl        Var(&TrmChr)     Type(*Char) Len(1)

                Dcl        Var(&All_TrmChr) Type(*Char) Len(1)

 

  • Declare the variable &XFF, which will be set to the value x'FF' for subsequent comparison with the parameter &All_TrmChr.

 

                Dcl        Var(&XFF)        Type(*Char) Len(1) Value(x'FF')

 

  • Change the hardcoded test for a leading zero to a test for the user-specified &TrmChr variable value.

 

                If Cond(&Char *EQ '0') Then(Do) 

 

                becomes

 

                If Cond(&Char *EQ &TrmChr) Then(Do) 

 

  • Change the logic for when no significant characters are found in the input string to test for the special value *TRMCHR (passed to the CPP as x'FF') and set the resulting character string to the appropriate user-specified value.

 

                ChgVar Var(&Char_Tgt) Value('0')

 

                becomes

 

                If Cond(&All_TrmChr *EQ &XFF) Then( +       

                   ChgVar Var(&Char_Tgt) Value(&TrmChr))    

                Else Cmd( +                                 

                   ChgVar Var(&Char_Tgt) Value(&All_TrmChr))

 

To compile the new CPP use either of the following commands:

 

CRTBNDCL PGM(TRMLFTCHR)

CRTCLPGM PGM(TRMLFTCHR)

 

As mentioned in the earlier article, "Going Where No Substring (%SST) Operation Can Go," if you are using the CRTBNDCL command to create an ILE program, make sure that you have the following PTFs applied to your system prior to compiling the CPP:

 

  • V5R4—SI39398
  • V6R1—SI39405
  • V7R1—SI39407

 

To test the latest version of the TRMLFTCHR command, you can use the following CL test program.

 

Pgm                                               

Dcl        Var(&Char10)   Type(*Char) Len(10)      

Dcl        Var(&Char50)   Type(*Char) Len(50)     

                                                  

ChgVar     Var(&Char10) Value(12.34)              

SndPgmMsg  Msg('Originally' *BCat &Char10)        

TrmLftChr  Var(&Char10)                            

SndPgmMsg  Msg('Now.......' *BCat &Char10)        

                                                  

ChgVar     Var(&Char10) Value(0)                  

SndPgmMsg  Msg('Originally' *BCat &Char10)        

TrmLftChr  Var(&Char10) AllTrmChr('?')             

SndPgmMsg  Msg('Now.......' *BCat &Char10)        

                                                  

ChgVar     Var(&Char10) Value(0)                  

SndPgmMsg  Msg('Originally' *BCat &Char10)        

TrmLftChr  Var(&Char10)             

SndPgmMsg  Msg('Now.......' *BCat &Char10)        

                                                  

ChgVar     Var(&Char10) Value('***ABC EF')        

SndPgmMsg  Msg('Originally' *BCat &Char10)        

TrmLftChr  Var(&Char10)                            

SndPgmMsg  Msg('Now.......' *BCat &Char10)        

                                                  

ChgVar     Var(&Char10) Value('***ABC EF')        

SndPgmMsg  Msg('Originally' *BCat &Char10)        

TrmLftChr  Var(&Char10) TrmChr(*)                  

SndPgmMsg  Msg('Now.......' *BCat &Char10)        

                                                  

ChgVar     Var(&Char50) Value('   ABCDEF')        

SndPgmMsg  Msg('Originally' *BCat &Char50)        

TrmLftChr  Var(&Char50) TrmChr(' ')                

SndPgmMsg  Msg('Now.......' *BCat &Char50)        

                                                  

EndPgm                                            

 

When the test program is run, you should see the following messages, which demonstrate various combinations of the three command parameters.

 

Originally 0000012.34      

Now....... 12.34           

Originally 0000000000      

Now....... ?               

Originally 0000000000      

Now....... 0               

Originally ***ABC EF        

Now....... ***ABC EF       

Originally ***ABC EF       

Now....... ABC EF          

Originally    ABCDEF       

Now....... ABCDEF          

 

But what if the CL program using TRMLFTCHR is reading a file, say, created by CPYSPLF, and encounters a report value of "     *1.23" (five blanks, an asterisk, and then the four characters 1.23) that needs to be formatted as simply 1.23 within the CL application program? In this case, we want to remove any combination of two different leading characters: blanks and asterisks. In the next article, we'll do just that. The next version of the TRMLFTCHR command will demonstrate how a user command can support the TRMCHR command parameter as a list of values.

Answer to Last Month's Program Puzzler

In the previous article, I presented a puzzle question: "Can you think of a way to eliminate the need for these DOFORs that are updating the input character string with a predetermined number of blank characters?" I suggested that you review the "Understanding the CHKKILL Program" article published in February of 2009. What you would have found in the article was a discussion of the Machine Interface (MI) Propagate Byte (PROPB) instruction. This instruction, documented here, copies a given byte value (for instance, a blank) a user-specified number of times to a variable location. Using the Propagate Byte instruction, you can eliminate the two DOFOR loops that are found in the TRMLFTCHR CPP.

 

The first DOFOR loop…

 

DoFor Var(&Char_Pos) From(1) To(&Char_Rem)   

      ChgVar Var(&Char_Tgt) Value(' ')       

      ChgVar Var(%ofs(&CharTgtPtr)) +        

               Value(%ofs(&CharTgtPtr) + 1)  

      EndDo                                  

 

…can be replaced with this statement:

 

CallPrc Prc('_PROPB') Parm((&Char_Tgt) +  

        (' ' *ByVal) (&Char_Rem *ByVal))  

 

The second loop…

 

DoFor Var(&Char_Pos) From(2) To(&Char_Siz)  

      ChgVar Var(&Char_Tgt) Value(' ')      

      ChgVar Var(%ofs(&CharTgtPtr)) +       

               Value(%ofs(&CharTgtPtr) + 1) 

      EndDo                                 

 

…can, in a similar fashion, be replaced with the two following statements:

 

ChgVar Var(&Char_Rem) Value(&Char_Siz - 1)  

CallPrc Prc('_PROPB') Parm((&Char_Tgt) +    

        (' ' *ByVal) (&Char_Rem *ByVal))    

 

Not only does the PROPB MI instruction allow us to type less CL source, it also runs faster than looping through the character string variable one byte at a time.

 

The TRMLFTCHR CPP examples used in this series of articles will continue to use the DOFOR implementations. Using DOFORs allows you to create the CPP as either an OPM program, using CRTCLPGM, or an ILE program, using CRTBNDCL. Imbedding MI instructions such as Propagate Byte directly into the CL source, on the other hand, can only be done with ILE CL.

More CL Questions?

Wondering how to accomplish a function in CL? Send your CL-related questions to me at This email address is being protected from spambots. You need JavaScript enabled to view it..

 

BLOG COMMENTS POWERED BY DISQUS

LATEST COMMENTS

Support MC Press Online

$

Book Reviews

Resource Center

  • SB Profound WC 5536 Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application. You can find Part 1 here. In Part 2 of our free Node.js Webinar Series, Brian May teaches you the different tooling options available for writing code, debugging, and using Git for version control. Brian will briefly discuss the different tools available, and demonstrate his preferred setup for Node development on IBM i or any platform. Attend this webinar to learn:

  • SB Profound WP 5539More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.

  • SB HelpSystems ROBOT Generic IBM announced the E1080 servers using the latest Power10 processor in September 2021. The most powerful processor from IBM to date, Power10 is designed to handle the demands of doing business in today’s high-tech atmosphere, including running cloud applications, supporting big data, and managing AI workloads. But what does Power10 mean for your data center? In this recorded webinar, IBMers Dan Sundt and Dylan Boday join IBM Power Champion Tom Huntington for a discussion on why Power10 technology is the right strategic investment if you run IBM i, AIX, or Linux. In this action-packed hour, Tom will share trends from the IBM i and AIX user communities while Dan and Dylan dive into the tech specs for key hardware, including:

  • Magic MarkTRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now!  Request Now.

  • SB HelpSystems ROBOT GenericForms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.

  • SB HelpSystems ROBOT GenericIT security is a top priority for businesses around the world, but most IBM i pros don’t know where to begin—and most cybersecurity experts don’t know IBM i. In this session, Robin Tatam explores the business impact of lax IBM i security, the top vulnerabilities putting IBM i at risk, and the steps you can take to protect your organization. If you’re looking to avoid unexpected downtime or corrupted data, you don’t want to miss this session.

  • SB HelpSystems ROBOT GenericCan you trust all of your users all of the time? A typical end user receives 16 malicious emails each month, but only 17 percent of these phishing campaigns are reported to IT. Once an attack is underway, most organizations won’t discover the breach until six months later. A staggering amount of damage can occur in that time. Despite these risks, 93 percent of organizations are leaving their IBM i systems vulnerable to cybercrime. In this on-demand webinar, IBM i security experts Robin Tatam and Sandi Moore will reveal:

  • FORTRA Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:

  • FORTRAManaging messages on your IBM i can be more than a full-time job if you have to do it manually. Messages need a response and resources must be monitored—often over multiple systems and across platforms. How can you be sure you won’t miss important system events? Automate your message center with the Robot Message Management Solution. Key features include:

  • FORTRAThe thought of printing, distributing, and storing iSeries reports manually may reduce you to tears. Paper and labor costs associated with report generation can spiral out of control. Mountains of paper threaten to swamp your files. Robot automates report bursting, distribution, bundling, and archiving, and offers secure, selective online report viewing. Manage your reports with the Robot Report Management Solution. Key features include:

  • FORTRAFor over 30 years, Robot has been a leader in systems management for IBM i. With batch job creation and scheduling at its core, the Robot Job Scheduling Solution reduces the opportunity for human error and helps you maintain service levels, automating even the biggest, most complex runbooks. Manage your job schedule with the Robot Job Scheduling Solution. Key features include:

  • LANSA Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.

  • LANSAWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed. Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

  • LANSASupply Chain is becoming increasingly complex and unpredictable. From raw materials for manufacturing to food supply chains, the journey from source to production to delivery to consumers is marred with inefficiencies, manual processes, shortages, recalls, counterfeits, and scandals. In this webinar, we discuss how:

  • The MC Resource Centers bring you the widest selection of white papers, trial software, and on-demand webcasts for you to choose from. >> Review the list of White Papers, Trial Software or On-Demand Webcast at the MC Press Resource Center. >> Add the items to yru Cart and complet he checkout process and submit

  • Profound Logic Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application.

  • SB Profound WC 5536Join us for this hour-long webcast that will explore:

  • Fortra IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn: