rexx
TRANSCRIPT
04/08/23 1
REXX
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ObjectivesObjectives
Introduction to REXX
Syntax and Functions
Advanced Concepts
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IntroductionIntroduction
What is REXX ?– Restructured EXtended eXecutor– Interpreted command language– Very useful for linking TSO, ISPF and other
functions– Useful for developing custom-made utilities
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Features of REXXFeatures of REXX
Ease of use
Free format
Convenient built-in functions
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Features of REXX (Cont...)Features of REXX (Cont...)
Debugging capabilities
Interpreted language
Extensive parsing capabilities
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Components of REXXComponents of REXX
InstructionsBuilt-in functionsTSO functionsData stack functions
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InstructionInstructionKeyword
– Tells the language processor to do something
Assignment– Gives a value to a variable or changes the current
value of a variable
Label– A symbolic name followed by a colon– Identifies a portion of the exec– Commonly used in subroutines and functions, and
with the CALL/SIGNAL instruction
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Instruction (Cont...)Instruction (Cont...)
Command (both REXX commands and host commands)
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Built-in functionsBuilt-in functions
These functions are built into the language processor
Provide convenient processing options
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TSO external functionsTSO external functions
Interact with the systemDo specific tasks for REXX
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Data stack functionsData stack functions
Store data for I/O Other types of processing
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Syntax of REXXSyntax of REXX
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Character Type of REXXCharacter Type of REXXA REXX instruction can be in lower case, upper
case, or mixed caseAlphabetic characters are changed to uppercase,
unless enclosed in single or double quotation marks
The two types of quotation marks cannot be mixed
If any word in the statement is a variable, REXX substitutes the value
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FormatFormatREXX uses a free formatA line usually contains one instruction except
when it ends with a comma (,) or contains a semi-colon (;). – Comma is the continuation character– Indicates that the instruction continues to the next
line– Semi-colon indicates the end of the instruction– Used to separate multiple instructions on one line
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Environment / AddressEnvironment / Address
ADDRESS TSO for native TSO commandsADDRESS ISPEXEC for ISPF servicesADDRESS ISREDIT for ISPF edit macros These are required to invoke the environment for
function calls
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Variables and expressionsVariables and expressions
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VariablesVariables
Character or group of characters that represents a valuee.g. count = 1000
Variable names can consist of:– A....Z / a - Z alphabetic– 0....9 numbers– @ # $ ¢ ? ! . _ special characters
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Variables (Cont...)Variables (Cont...)
Restrictions on the variable name are:– The first character cannot be 0 through 9 or a period
(.)– The variable name cannot exceed 250 bytes– The variable name should not be RC, SIGL, or
RESULT, which are REXX special variables
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ParsingParsingSeparates data by comparing the data to a
template (or pattern of variable names)Preserves the case of the input dataPARSE UPPER converts data to uppercaseSeparators in a template can be
– blank, – string,– variable, or– number that represents column position
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ParsingParsing
Blank - an example– Each variable name gets one word of data in
sequence except for the last, which gets the remainder of the data
– PARSE VALUE ‘Value with Blanks.’ WITH pattern type
• pattern contains ‘Value’
• type contains ‘ with Blanks.’
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ParsingParsing
Blank - another example– PARSE VALUE ‘Value with Extra Variables.’
WITH data1 data2 data3 data4 data5• data1 contains ‘Value’
• data2 contains ‘with’
• data3 contains ‘Extra’
• data4 contains ‘Variables.’
• data5 contains ‘’
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ParsingParsing
Substitution - an example– PARSE VALUE ‘Value with Periods in it.’ WITH
pattern . type .– pattern contains ‘Value’– type contains ‘Periods’– the periods replace the words “with” and “in it.”
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ParsingParsing
Separators - an example– phrase = ‘Dun & Bradstreet’– PARSE VAR phrase part1 ‘&’ part2– part1 contains ‘Dun ’– part2 contains ‘ Bradstreet’
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ParsingParsing
Number: Numbers in a template to indicate the column at which data must be separated – Unsigned integer indicates an absolute column
position and – Signed integer indicates a relative column
position
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ParsingParsing
Absolute column position– An unsigned integer or an integer prefixed with an
equal sign (=) in a template – The first segment starts at column 1 and goes up to,
but does not include, the information in the column number specified
– The subsequent segments start at the column numbers specified
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ParsingParsing
Absolute column position - an example – quote = ‘Dun & Bradstreet’– PARSE VAR quote part1 6 part2
• part1 contains ‘Dun &’
• part2 contains ‘Bradstreet’
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ParsingParsing
Absolute column position - another example – quote = ‘Dun & Bradstreet’– PARSE VAR quote part1 5 part2 7 part3 1 part4– part1 contains ‘Dun’– part2 contains ‘&’– part3 contains ‘Bradstreet’– part4 contains ‘Dun & Bradstreet’
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ParsingParsing
Relative column position– A signed integer in a template separates the data
according to relative column position– The starting position is relative to the starting
position of the preceding part. – Can be either positive (+) or negative (-)
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ParsingParsing
Relative column position - an example– quote = ‘Dun & Bradstreet’– PARSE VAR quote part1 +5 part2 +5 part3 – part1 contains ‘Dun &’– part2 contains ‘ Brad’– part3 contains ‘street’
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ParsingParsing
Variables– Define and use variables to provide further flexibility
of a PARSE VAR instruction– Define the variable prior to the parse instruction– Enclose the variable in parenthesis - this variable
must be an unsigned integer– Use a sign outside the parenthesis to indicate how
REXX is to interpret the unsigned integer– REXX substitutes the numeric value for the variable
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ParsingParsing
Variables - an example– quote = ‘Dun & Bradstreet’– movex = 4– PARSE VAR quote part5 +6 part6 +4 part7
-(movex) part8– part5 contains ‘Dun &’– part6 contains ‘Brad’– part7 contains ‘street’– part8 contains ‘Bradstreet’
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ExpressionsExpressions
Something that needs to be calculated/evaluatedConsists of numbers, variables, or strings, and
one or more operatorsFour types of operators
– Arithmetic– Comparison– Logical and– Concatenation
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Arithmetic OperatorsArithmetic Operators
Work on valid numeric constants or on variables that represent valid numeric constants• + Add• - Subtract• -number Negate the number• +number Add the number to 0
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Arithmetic Operators (Cont...)Arithmetic Operators (Cont...)
– * Multiply– ** Raise a number to a whole number power– / Divide– % Divide and return a whole number without a
remainder (quotient only)– // Divide and return the remainder only
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Arithmetic Operators - PriorityArithmetic Operators - Priority
Priority from maximum to minimum– - + Prefix operators– ** Power (exponential)– * / % // Multiplication and division– + - Addition and subtraction
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Comparison operatorsComparison operatorsDo not return a number valueReturn either a true or false response in terms of
1 or 0 respectively– == Strictly Equal– = Equal– > Greater than– < Less than– >= Greater than or equal to– <= Less than or equal to
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Comparison operators (Cont...)Comparison operators (Cont...)
– \== Not strictly equal– \= Not equal– >< Greater than or less than (same as not equal)– \< Not less than– \> Not greater than
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Strictly Equal and Equal OperatorsStrictly Equal and Equal Operators
When two expressions are strictly equal, everything including the blanks and case (when the expressions are characters) is exactly the same
When two expressions are equal, they are resolved to be the same
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Logical OperatorsLogical Operators
Return a true (1) or false (0) value when processed
Combine two comparisons and return the true (1) or false (0) value depending on the results of the comparisons
Used in complex conditional instructionsCan act as checkpoints to screen unwanted
conditions
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Logical Operators (Cont...)Logical Operators (Cont...)
The logical operators are– & AND
Returns 1 if both comparisons are true– | Inclusive OR
Returns 1 if at least one comparison is true– && Exclusive OR
Returns 1 if only one comparison (but not both) is true
– Prefix \ Logical NOTReturns the opposite response
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Concatenation operatorsConcatenation operators
Combine two terms into oneTerms can be strings, variables, expressions, or
constantsConcatenation can be significant in formatting
output
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Concatenation operators (Cont...)Concatenation operators (Cont...)
blankconcatenate terms, one blank in betweene.g. TRUE BLUE result is TRUE BLUE
|| concatenate terms, no blanks in betweene.g. “a”||”.b” result is a.b
abuttal concatenate terms, no blanks in betweene.g. per_cent‘%’ if per_cent = 50, result is 50%
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Overall Operator PriorityOverall Operator Priority \ ¬ - + Prefix operators** Power (exponential)* / % // Multiply and divide+ - Add and subtractblank || abuttal Concatenation operators== = >< Comparison operators& Logical AND | && inclusive OR, exclusive
OR
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Control of program flow
Control of program flow
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Conditional instructionsConditional instructions
Instructions which set up at least one condition in the form of an expression
IF/THEN/ELSE, and
SELECT/WHEN/OTHERWISE
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IF constructIF construct
Can direct the execution of an exec to one of two choices
IF expression THEN instructionELSE instruction
for more than one instruction for a condition, begin the set of instructions with a DO and end them with an END
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IF construct (Cont...)IF construct (Cont...) IF expression THEN
DOinstructioninstruction
ENDELSE
DOinstructioninstruction
END
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SELECT constructSELECT construct
can direct the execution to one of many choices.SELECT
WHEN expression THEN instructionWHEN expression THEN instruction:OTHERWISEinstruction(s)
END
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SELECT constructSELECT construct
for more than one instruction for a possible path, begin the set of instructions with a DO and end them with an END
However, if more than one instruction follows the OTHERWISE keyword, DO and END are not necessary
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Looping instructionsLooping instructions
Tell the language processor to repeat a set of instructions
A loop can repeat a specified number of times orCan use a condition to control repeatingTwo types of loops
– Repetitive repeat instructions a certain number of times
– Conditional use a condition to control repeating
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Repetitive loopsRepetitive loops
Repeat a set of instructions a specified number of times– e.g. DO i = 1 to 5
SAY “Hello !”END
The step can also be controlled e.g. DO i = 1 to 10 STEP 2
SAY “Hello !”END
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Repetitive loopsRepetitive loops
DO FOREVER/END - infinite loopsEXIT when a condition is reached
LEAVE instruction - leaves the loope.g. DO FOREVER
IF X = 0 THEN LEAVE
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Conditional loopsConditional loops
DO WHILE – DO WHILE expression
instruction(s)END
– Test the expression before the loop executes the first time and repeat only when the expression is true
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Conditional loopsConditional loops
DO UNTIL– DO UNTIL expression
instruction(s)END
– Test the expression after the loop executes at least once and repeat only when the expression is false
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Interrupt instructionsInterrupt instructions
Tell the language processor to leave the exec entirely or
leave one part of the exec and go to another part either permanently or temporarily
These are– EXIT– SIGNAL– CALL/RETURN
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EXITEXIT
Causes an exec to unconditionally endReturn to where the exec was invokedCan also return a value to the caller of the
exec
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SIGNAL labelSIGNAL label
Interrupts the normal flow of an execCauses control to pass to a specified labelUnlike CALL, SIGNAL does not return to a
specific instruction to resume executionWhen SIGNAL is issued from within a loop, the
loop automatically ends
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CALL / RETURNCALL / RETURN
When calling an internal subroutine, CALL passes control to a label specified after the CALL keyword
When the subroutine ends with the RETURN instruction, the instructions following CALL are executed
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CALL / RETURNCALL / RETURN
When calling an external subroutine, CALL passes control to the exec name that is specified after the CALL keyword
When the external subroutine completes, the RETURN instruction returns to where you left off in the calling exec
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Functions and SubroutinesFunctions and Subroutines
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FunctionsFunctionsSequence of instructions that can
– Receive data– Process that data, and – Return a value
All functions return a value to the exec that issued the function call
Syntax is function(arguments)No space between the function name and the left
parenthesis
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Functions - parametersFunctions - parameters
Up to 20 arguments separated by commas– Blank function( )– Constant function(55)– Symbol function(symbol_name)– Literal function(‘With a literal string’)– function(function(arguments))
Another function– function(‘With a literal string’, 55, option)
Combination of argument types
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Functions - TypesFunctions - Types
Built-in functions built into the language processor
User-written functions -- – Written by an individual user or supplied by an
installation – Internal function is part of the current exec that starts
at a label– External function is a self-contained program or exec
outside of the calling exec
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Functions - Types
User-written functions – Example/*REXX*/
f=INIT_RTN(2,5) say f /* it displays the result of user written
function */ EXIT INIT_RTN:
arg a,b c=a+b
RETURN c
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Built-in functionsBuilt-in functions
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Arithmetic functionsArithmetic functions
ABS Returns the absolute value of the input number
MAX Returns the largest number from the list
MIN Returns the smallest number from the list specified
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Arithmetic functions
ABS('12.3') -> 12.3
ABS(' -0.307') -> 0.307
MAX(-7,-3,-4.3) -> -3
MAX(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,MAX(20,21)) -> 21
MIN(12,6,7,9) -> 6
MIN(17.3,19,17.03) -> 17.03
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Arithmetic functionsArithmetic functions
RANDOM() Returns a quasi-random, non-negative whole number in the range specified
SIGN Returns a number that indicates the sign of the input number
TRUNC Returns the integer part of the input number, and optionally a specified number of decimal places
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Arithmetic functionsArithmetic functionsSIGN('12.3') -> 1
SIGN(' -0.307') -> -1
SIGN(0.0) -> 0
TRUNC(12.3) -> 12
TRUNC(127.09782,3) -> 127.097
TRUNC(127.1,3) -> 127.100
TRUNC(127,2) -> 127.00
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Comparison functionsComparison functionsCOMPARE
– Returns 0 if the two input strings are identical– Returns the position of the first character that does
not match
DATATYPE Returns a value indicating data type of the input string, such as a number or character
SYMBOL Returns this state of the symbol (variable, literal, or bad)
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Comparison functionsComparison functions
COMPARE(ACC,ACD) /* 3 */
DATATYPE(123) /* NUM OR CHAR */
A.3=5; J=3 ;
SYMBOL('J') /* VAR */
SYMBOL('K') /* LIT */
SYMBOL('A.J') /* VAR */
SYMBOL('552') /* LIT CONSTANT SYMBOL */
SAY SYMBOL('+') /* BAD NOT A VALID SYMBOL */
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Conversion functionsConversion functions
Convert one type of data representation to another type of data representation
B2X Binary to hexadecimalC2D Character to DecimalC2X Character to HexadecimalD2C Decimal to Character
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Conversion functionsConversion functions
D2X Decimal to HexadecimalX2B Hexadecimal to binaryX2C Hexadecimal to CharacterX2D Hexadecimal to Decimal
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Conversion functionsConversion functions
M= B2X(0101) ; SAY M /* BINARY TO HEXADECIMAL 5 */
M= C2D(ABC); SAY M /* CHARACTER TO DECIMAL 12698307 */
M= C2X(ABC); SAY M /* CHARACTER TO HEXADECIMAL C1C2C3 */
M= D2C(123); SAY M /* DECIMAL TO CHARACTER # */
M= D2X(123); SAY M /* DECIMAL TO HEXADECIMAL 7B */
M = X2B(ABC); SAY M /* HEXADECIMAL TO BINARY 101010111100 */
M = X2C(ABC); SAY M /* HEXADECIMAL TO CHARACTER :: */
M = X2D(ABC); SAY M /* HEXADECIMAL TO DECIMAL 2748 */
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Formatting functionsFormatting functionsCENTER/CENTRE
Returns a string of a specified length with the input string centered in it, with pad characters added as necessary to make up the length
COPIES Returns the specified number of concatenated copies of the input string
FORMAT Returns the input number, rounded and formatted to the number of digits specified
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Formatting functionsFormatting functions
CENTER(ABC,5) /* ' ABC ' */
CENTER(ABC,10,'-') /* '---ABC----' */
CENTRE(ABC,9,'-') /* '---ABC---' */
COPIES(‘-’,6) ------
FORMAT('1.73',4,3) ' 1.730'
FORMAT('-.76',4,1) ' -0.8'
FORMAT('3.03',4) ' 3.03'
FORMAT(' - 12.73',,4) '-12.7300'
FORMAT(' - 12.73') '-12.73'
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Formatting functionsFormatting functions
JUSTIFY Returns a specified string formatted by adding pad characters between words to justify to both margins
LEFT Returns a string of the specified length, truncated or padded on the right as needed
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Formatting functionsFormatting functions
RIGHT Returns a string of the specified length, truncated or padded on the left as needed
SPACE Returns the words in the input string with a specified number of pad characters between each word
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Formatting functionsFormatting functionsJUSTIFY('THE BLUE SKY',14) -> 'THE BLUE SKY'
JUSTIFY('THE BLUE SKY',8) -> 'THE BLUE'
JUSTIFY('THE BLUE SKY',9) -> 'THE BLUE'
JUSTIFY('THE BLUE SKY',9,'+') -> 'THE++BLUE'
LEFT('ABC D',8) -> 'ABC D '
LEFT('ABC D',8,'.') -> 'ABC D...'
LEFT('ABC DEF',7) -> 'ABC DE'
RIGHT('ABC D',8) -> ' ABC D'
RIGHT('ABC DEF',5) -> 'C DEF'
RIGHT('12',5,'0') -> '00012'
SPACE('ABC DEF ') -> 'ABC DEF'
SPACE(' ABC DEF',3) -> 'ABC DEF'
SPACE('ABC DEF ',1) -> 'ABC DEF'
SPACE('ABC DEF ',0) -> 'ABCDEF'
SPACE('ABC DEF ',2,'+') -> 'ABC++DEF'
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String manipulating functionsString manipulating functionsABBREV Returns a string indicating if
one string is equal to the specified number of leading characters of another string
DELSTR Returns a string after deleting a specified number of characters, starting at a specified point in the input string
DELWORD Returns a string after deleting a specified number of words, starting at a specified word in the input string
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String manipulating functionsString manipulating functionsABBREV('PRINT','PRI',3) -> 1
ABBREV('PRINT','PRI') -> 1
ABBREV('PRINT','PRI',4) -> 0
ABBREV('PRINT','PRY') -> 0
ABBREV('PRINT','',1) -> 0
DELSTR('ABCD',3) -> 'AB'
DELSTR('ABCDE',3,2) -> 'ABE'
DELSTR('ABCDE',6) -> 'ABCDE'
DELWORD('NOW IS THE TIME',2,2) -> 'NOW TIME'
DELWORD('NOW IS THE TIME ',3) -> 'NOW IS '
DELWORD('NOW IS THE TIME',5) -> 'NOW IS THE TIME'
DELWORD('NOW IS THE TIME',3,1) -> 'NOW IS TIME'
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String manipulating functionsString manipulating functionsFIND Returns the word number
of the first word of a specified phrase found within the input string
INDEX Returns the character position of the first character of a specified string found in the input string
INSERT Returns a character string after inserting one input string into another string after a specified character position
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String manipulating functionsString manipulating functions
FIND('NOW IS THE TIME','IS THE TIME') -> 2
FIND('NOW IS THE TIME',' THE') -> 3
FIND('NOW IS THE TIME',' HE') -> 0
INDEX('abcdef','cd') -> 3
INDEX('abcdef','xd') -> 0
INDEX('abcabc','bc',3) -> 5
INDEX('abcabc','bc',6) -> 0
INSERT(' ','abcdef',3) -> 'abc def'
INSERT('123','abc',5,6) -> 'abc 123 '
INSERT('123','abc',5,6,'+') -> 'abc++123+++'
INSERT('123','abc') -> '123abc'
INSERT('123','abc',,5,'-') -> '123--abc'
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String manipulating functionsString manipulating functionsLASTPOS Returns the starting character
position of the last occurrence of one string in another
LENGTH Returns the length of the input string
OVERLAY Returns a string that is the target string overlaid by a second input string
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String manipulating functionsString manipulating functionsLASTPOS(' ','abc def ghi') -> 8 LASTPOS(' ','abcdefghi') -> 0 LASTPOS('xy','efgxyz') -> 4 LASTPOS(' ','abc def ghi',7) -> 4 LENGTH('abcdefgh') -> 8 LENGTH('abc defg') -> 8 LENGTH('') -> 0
OVERLAY(' ','abcdef',3) -> 'ab def' OVERLAY('.','abcdef',3,2) -> 'ab. ef' OVERLAY('qq','abcd') -> 'qqcd' OVERLAY('qq','abcd',4) -> 'abcqq' OVERLAY('123','abc',5,6,'+') -> 'abc+123+++' M=OVERLAY('D',, OVERLAY('C',, OVERLAY('B','A',15),25),35)
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String manipulating functionsString manipulating functionsPOS Returns the character position of
one string in another
REVERSE Returns a character string, the characters of which are in reverse order (swapped end for end)
STRIP Returns a character string after removing leading or trailing characters or both from the input string
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String manipulating functionsString manipulating functionsPOS('day','Saturday') -> 6
POS('x','abc def ghi') -> 0
POS(' ','abc def ghi') -> 4
POS(' ','abc def ghi',5) -> 8
REVERSE('ABc.') -> '.cBA'
REVERSE('XYZ ') -> ' ZYX'
STRIP(' ab c ') -> 'ab c'
STRIP(' ab c ','L') -> 'ab c '
STRIP(' ab c ','t') -> ' ab c'
STRIP('12.7000',,0) -> '12.7'
STRIP('aabbca',,a) -> 'bbc'
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String manipulating functionsString manipulating functionsSUBSTR Returns a portion of the
input string beginning at a specified character position
SUBWORD Returns a portion of the input string starting at a specified word number
TRANSLATE Returns a character string with each character of the input string translated to another character or unchanged
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String manipulating functionsString manipulating functionsSUBSTR('abc',2) -> 'bc'
SUBSTR('abc',2,4) -> 'bc '
SUBSTR('abc',2,6,'.') -> 'bc....'
SUBWORD('Now is the time',2,2) -> 'is the'
SUBWORD('Now is the time',3) -> 'the time'
SUBWORD('Now is the time',5) -> ''
TRANSLATE('abbc','&','b') -> 'a&&c'
TRANSLATE('abcdef','12','ec') -> 'ab2d1f'
TRANSLATE('abcdef','12','abcd','.') -> '12..ef'
TRANSLATE('APQRV',,'PR') -> 'A Q V'
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String manipulating functionsString manipulating functionsVERIFY
Returns a number indicating whether an input string is composed only of characters from another input string or returns the character position of the first unmatched character
WORD Returns a word from an input string as indicated by a specified number
WORDINDEX Returns the character position in an input string of the first character in the specified word
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String manipulating functionsString manipulating functions VERIFY('123','1234567890') -> 0
VERIFY('1Z3','1234567890') -> 2
VERIFY('AB4T','1234567890') -> 1
VERIFY('AB4T','1234567890','M') -> 3 /*Match */
VERIFY('AB4T','1234567890','N') -> 1
VERIFY('1P3Q4','1234567890',,3) -> 4
VERIFY('123','',N,2) -> 2
VERIFY('ABCDE','',,3) -> 3
VERIFY('AB3CD5','1234567890','M',4) -> 6
WORD('a b c',2) -> 'b'
WORDINDEX('Now is the time',3) -> 8
WORDINDEX('Now is the time',6) -> 0
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String manipulating functionsString manipulating functionsWORDLENGTH Returns the length of a
specified word in the input string
WORDPOS Returns the word number of the first word of a specified phrase in the input string
WORDS Returns the number of words in the input string
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String manipulating functionsString manipulating functionsWORDLENGTH('Now is the time',2) -> 2
WORDLENGTH('Now comes the time',2) -> 5
WORDLENGTH('Now is the time',6) -> 0
WORDPOS('the','now is the time') -> 3
WORDPOS('The','now is the time') -> 0
WORDPOS('is the','now is the time') -> 2
WORDPOS('is the','now is the time') -> 2
WORDS('Now is the time') -> 4
WORDS(' ') -> 0
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Date formatsDate formats
Syntax of the date function id DATE(option)– A variety of options are available– The full option, or it’s first alphabet, can be passed as
argument– A list of options follows
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Date formatsDate formats
Base(or Basedate) Returns the number of complete days (that is, not including the current day) since and including the date, January 1, 0001, in the format: dddddd (no leading zeros or blanks)– The expression DATE(‘B’)//7 returns a number in the
range 0-6, where 0 is Monday and 6 is Sunday– Thus, this function can be used to determine the day
of the week independent of the language
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Date formatsDate formatsCentury Returns the number of days,
including the current day, since and including January 1 of the last year that is a multiple of 100 in the format: ddddd (no leading zeros)Example: A call to DATE(C) is made on March 13, 1992, so the number of days from January 1, 1900, to March 13, 1992, (33675) is returned
Days Returns the number of days, including the current day, so far in this year in the format: ddd (no leading zeros or blanks)
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Date formatsDate formats
European Returns date in dd/mm/yy format
Julian Returns date in yyddd format
Month Returns full English name of the current month, for example, August
Normal Returns date in the format: dd mon yyyy. This is the default
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Date formatsDate formats Ordered Returns date in the
format: yy/mm/dd (suitable for sorting)
Standard / Sorted Returns date in the format: yyyymmdd (suitable for sorting)
USA Returns date in mm/dd/yy format
Weekday Returns the English name for the day of the week, in mixed case, for example, Tuesday
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Time formatsTime formats
Syntax of the Time function is TIME(option)– A variety of options are available– The full option, or it’s first alphabet, can be passed as
the argument– A list of options follows
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Time formatsTime formatsCivil
– Returns the time in Civil format: hh:mmxx– The hours take the values 1 through 12– The minutes take the values 00 through 59– The minutes are followed immediately by the letters
am or pm– The hour has no leading zero– The minute field shows the current minute (rather
than the nearest minute) for consistency with other TIME results
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Time formatsTime formats
Elapsed – Returns sssssssss.uuuuuu, the number of
seconds.microseconds since the elapsed-time clock was started or reset
– No leading zeros or blanks– Setting of NUMERIC DIGITS does not affect the
number– The fractional part always has six digits
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Time formatsTime formats
Hours – Returns up to two characters – Gives the number of hours since midnight – Format is hh– No leading zeros or blanks, except for a result of 0
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Time formatsTime formats
Long – Returns time in the format: hh:mm:ss.uuuuuu
(uuuuuu is in microseconds)– The first eight characters of the result follow the same
rules as for the Normal form– The fractional part is always six digits
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Time formatsTime formats
Minutes – Returns up to four characters – Gives the number of minutes since midnight – Format is mmmm – No leading zeros or blanks, except for a result of 0
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Time formatsTime formats
Normal– This is the default– Returns the time in the format hh:mm:ss– Hours take the values 00 through 23– Minutes and seconds take 00 through 59– All these are always two digits– Any fractions of seconds are ignored (times are never
rounded up)
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Time formatsTime formats
Reset– Returns sssssssss.uuuuuu, the number of
seconds.microseconds since the elapsed-time clock was started or reset
– Also resets the elapsed-time clock to zero– The number has no leading zeros or blanks– Setting of NUMERIC DIGITS does not affect the
number– The fractional part always has six digits
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Time formatsTime formats
Seconds– Returns up to five characters– Gives the number of seconds since midnight– Format is sssss– No leading zeros or blanks, except for a result of 0
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SubroutinesSubroutines
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SubroutinesSubroutines
Series of instructions that an exec invokes Performs a specific taskThe subroutine is invoked by the CALL
instructionWhen the subroutine ends, it returns control to
the instruction that directly follows the subroutine call
The instruction that returns control is the RETURN instruction
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SubroutinesSubroutinesSubroutines may be
– Internal and designated by a label, or – external and designated by the member name that
contains the subroutine
IMPORTANT NOTE– Internal subroutines generally appear after the main
part of the exec. So, when there is an internal subroutine, it is important to end the main part of the exec with the EXIT instruction
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Using subroutinesUsing subroutines
Sharing information can be done by
– Passing variables
– Passing arguments
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Passing VariablesPassing Variables
Main exec and subroutine share the same variables by name
Value of the variable is the same irrespective of where it has been set
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An exampleAn exampleNUMBER1 = 5
NUMBER2 = 10
CALL SUB1
SAY ANSWER (DISPLAYS 15)
EXIT
SUB1:
ANSWER = NUMBER1 + NUMBER2
RETURN
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Shielding VariablesShielding Variables
Done by using PROCEDURE instruction immediately after the subroutine label
All variables used in the subroutine become local to the subroutine
Shielded from the main part of the exec
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An exampleAn example
NUMBER1 = 10
CALL SUB2
SAY NUMBER1 NUMBER2(DISPLAYS 10 NUMBER2)
EXIT SUB2: PROCEDURE
NUMBER1 = 7
NUMBER2 = 5
RETURN
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Exposing VariablesExposing Variables
To protect specific variables– use the EXPOSE option with the
PROCEDURE instruction followed by the variables that are to remain exposed to the subroutine
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An exampleAn exampleNUMBER1 = 10
CALL SUB3
SAY NUMBER1 NUMBER2 (DISPLAYS 7 NUMBER2)
EXIT
SUB3: PROCEDURE EXPOSE NUMBER1
NUMBER1 = 7
NUMBER2 = 5
RETURN
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Passing ArgumentsPassing ArgumentsPassed in main EXEC by
– CALL subroutine_name argument1, argument2, argument3, etc.
– Up to 20 arguments can be passed
Received in subroutine by– ARG arg1, arg2, arg3, etc.– The names of the arguments on the CALL and the
ARG instructions need not be the same– information is passed by position, and not by name
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An exampleAn exampleLENGTH = 10
WIDTH = 7
CALL SUB4 LENGTH, WIDTH
SAY ‘THE PERIMETER IS ‘ RESULT ‘METERS’
EXIT
SUB4:
ARG LEN, WID
PERIM = 2 * ( LEN + WID)
RETURN PERIM
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Compound variablesCompound variables
Compound variable is a single-dimensional array, denoted by <variable name>.
The variable name itself can be more than one level
The rules that apply to a variable name also apply to a compound variable
Very useful in array manipulation, input/output etc.
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Compound variables
PGM. = " "
PGM.. = " "
PGM...= " " /* Initializing the compound variables with null */
PGM....= " "
PGM..... = " "
PGM.1 = 'ABC'
PGM.1.1 = 'DEF' /* Assigning the compound variables */
PGM.1.1.1 = 'GHI'
PGM.1.1.1.1 = 'IJK'
PGM.1.1.1.1.1 = 'LMN'
PGM.J = 'ABC' /* J,K,L,M,N can be variables */
PGM.J.K = 'DEF'
PGM.J.K.L = 'GHI'
PGM.J.K.L.M = 'IJK'
PGM.J.K.L.M.L = 'LMN'
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Using REXXUsing REXX
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ConventionsConventions
Datasets are named as<high level qualifier>.REXX.EXEC
The last level .EXEC is optionalEach member must have the first line
as /* REXX */This makes the command processor (TSO)
invoke the REXX interpreter
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ConcatenationsConcatenations
Datasets containing REXX EXECs must be concatenated to SYSEXEC or SYSPROC
Concatenation to SYSEXEC makes execution faster, as it is above SYSPROC in the search order
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ExecutionExecution
How and where can REXX execs be executed– From TSO READY prompt (if no ISPF
services are used)– From inside ISPF– From inside another exec
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Online Execution
From ISPF command line prompt
TSO EXEC ‘XXX.XXX.REXX(MYREXX)’ EXEC From ISPF Command Shell(Option 6 in primary
panel)
EXEC ‘XXX.XXX.REXX(MYREXX)’ EXEC VIEW XXX.XXX.REXX
Command ===>
Name Prompt
EXEC_____ MYREXX
_________ MYREX2
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Batch Execution
//--------JOBCARD--------
//ISPF1 EXEC PGM=IKJEFT01
//SYSPRINT DD SYSOUT=*
//SYSTSPRT DD SYSOUT=*
//SYSOUT DD SYSOUT=*
//SYSTSIN DD *
EX ‘XXX.XXX.REXX(MYREXX)‘
//*
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Data stackData stack
Place for storing variables temporarilyManipulated using PUSH and QUEUENo limits on the length and format of the data
itemsTheoretically no limit on the number of items to
be stacked - limited only by practical considerations
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Data Stack
Stack
Queue A1 Queue A2 Queue A3
A1A2A3
Push A4 Push A5 Push A6 A6
A5A4A1A2A3
Pull Stmt A6Pull Stmt A5Pull Stmt A4Pull Stmt A3Pull Stmt A2Pull Stmt A1
Instruction Result
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Data stackData stack
PUSH works LIFO (Last-In-First-Out)– puts items to the top of the stack
QUEUE works FIFO (First-In-First-Out)– puts items on the bottom of the stack
In both cases, elements are removed by PULLQUEUED() gives the number of items put on a
stack in a single EXEC
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Data Stack - example/*REXX*/ QUEUE AMD1 QUEUE AMD2 "NEWSTACK" QUEUE AMD3 /*FIFO*/ QUEUE AMD4 PUSH AMD5 /*LIFO*/ PULL A PULL A PULL A PULL A PULL A "DELSTACK" PULL A "DELSTACK" PULL A EXIT
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Input/Output processingInput/Output processing
Operations with datasetsAll datasets with a defined record format
are allowed (except RECFM=U)
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DISKRDISKR
EXECIO DISKR for reading the dataset/member– “EXECIO 0 DISKR mydd (OPEN” - just opens the
dataset– “EXECIO 25 ...”- reads 25 lines– “EXECIO * ...” - reads all the lines– “EXECIO * DISKR myindd 100 (FINIS” - reads
all lines from line 100• In all the above cases, the lines are read on to the STACK
– “EXECIO * DISKR myindd (STEM newvar.” - reads into a stem of variables called newvar
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DISKWDISKW
Options for DISKR also hold for DISKWWrites to dataset/memberCan be written from stem/stackNumerous other options available for
positioning, skipping, LIFO/FIFO etc.
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ExampleExampleUse REXX to
– List all datasets following a particular pattern– For each dataset, list all the members starting with a
particular pattern
This can be done by– Using LMDLIST to get the dataset list– Then using LMMLIST on each dataset to get the
member list– Match patterns, and display appropriate members
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Example:/*REXX*/ ARG DSNI DSNO /*DSNI="IMS5.CA7.OVER" DSNO="PXX.IMS5.CA7.OVER" */ CALL INIT_RTN CALL MAIN_RTN EXIT INIT_RTN: DROP INP. DROP MEM. PROCLIB=DSNI PROCLIB1="'"PROCLIB"'" ADDRESS TSO A=OUTTRAP("MEM.","*") "LISTDS "procLIB1" MEMBERS"
A=OUTTRAP("OFF") SAY MEM.0 RETURN
MAIN_RTN: DO J=7 TO MEM.0 XTEMP=STRIP(MEM.J) DSNAME=PROCLIB||"("||XTEMP||")" DNAME = "'" || DSNAME || "'" OSNAME=DSNO||"("||XTEMP||")" ONAME = "'" || OSNAME || "'" DROP INP. "ALLOC DDN(INPFL) DSN("DNAME") SHR REUSE"
"EXECIO * DISKR INPFL (STEM INP. FINIS)" "FREE DDN(INPFL)" "ALLOC DDN(ONPFL) DSN("ONAME") SHR
REUSE" "EXECIO * DISKW ONPFL (STEM INP. FINIS)" "FREE DDN(ONPFL)" DROP INP. END RETURN
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Debugging REXX ExecsDebugging REXX Execs
Trace ?I (Intermediates)– Stops execution after each instruction
Trace ?R (Results)– Displays the result of execution of each step, but runs
continuously
These help to trace the progress of the EXECEXECUTIL TS (Trace start) and TE (trace end)
can also be used to start and end the tracing of a REXX
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Debugging REXX ExecsDebugging REXX Execs
RC Return code of the last instruction executed
SIGLSet to the line number from where the transfer occurred
These variables can also be used to trace the exec
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TSO External functionsTSO External functions
All TSO commands can be issuedEnclose them within quotation marks
– e.g. "LISTDS ‘my.dataset’ STATUS"
Variables can also be passed– e.g. "LISTDS" name "STATUS"– here, name is a variable used in the REXX
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LISTDS ‘XXX.XXX.REXX' STATUS
XXX.XXX.REXX
--RECFM-LRECL-BLKSIZE-DSORG--DDNAME---DISP
FB 80 27920 PO SYS00007
KEEP --VOLUMES--
TPT047
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ISPF functionsISPF functions
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PanelsPanels
Display panels, accept data and pass on data for processing
Syntax is– ADDRESS ISPEXEC– “Display panel(XXXXXX)”
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PANEL – EXAMPLE
)ATTR @ TYPE(TEXT) INTENS(HIGH) COLOR(YELLOW) ~ TYPE(TEXT) INTENS(HIGH) COLOR(PINK) $ TYPE(TEXT) INTENS(HIGH) COLOR(RED) # TYPE(OUTPUT) INTENS(HIGH) COLOR(TURQ) ! TYPE(TEXT) INTENS(HIGH) COLOR(WHITE) * TYPE(TEXT) INTENS(LOW) COLOR(RED) HILITE(REVERSE) _ TYPE(INPUT) INTENS(LOW) COLOR(TURQ) + TYPE(TEXT) INTENS(LOW) % TYPE(TEXT) INTENS(HIGH) COLOR(WHITE) )BODY + +COMMAND ==>_PCMD + + ! USER:#UID + + * MAIN-PANEL * ! DATE:#DAT + + %------------------+ ! TIME:#TIM + + @OPTION ==>_O+ + ! 1.~ PTR SOURCE ANALYSIS + ! 2.~ PTR JOB ANALYSIS + )INIT .CURSOR='O' &PCMD='' &O='' )PROC VPUT (O) PROFILE VER(&O,NB,LIST,'1','2','3') )END
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Panel example)ATTR @ TYPE(OUTPUT) INTENS(HIGH) # TYPE(OUTPUT) INTENS(LOW) COLOR(YELLOW) * TYPE(TEXT) INTENS(LOW) COLOR(GREEN) HILITE(REVERSE) TYPE(OUTPUT) INTENS(LOW) COLOR(TURQ) % TYPE(TEXT) INTENS(LOW) COLOR(TURQ) HILITE(USCORE) + TYPE(TEXT) INTENS(LOW) )BODY +-----------------* ARRAY OF VARIABLES +--------------------------+ +COMMAND ==>_ZCMD +SCROLL ==>_SAMT +
+ + +JOBNAME1 STEP1 PGM1 DDN1 DSN1 DISP1)MODEL @JOBNAME1 #STEP1 PGM1 @DDN1 #DSN1 DISP)INIT &SAMT=CSR &ZCMD='' )END
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TablesTables
All table services like TBCREATE, TBADD, TBUPDATE, TBDELETE etc.
Syntax is– ADDRESS ISPEXEC– “TBADD tbl-name ....”– “TBDELETE tbl-name...” etc.
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ISPF Tables - Syntax"ISPEXEC LIBDEF ISPTLIB DATASET ID(“XXX.XXX") "
"ISPEXEC LIBDEF ISPTABL DATASET ID(“XXX.XXX") "
COLUMNS = "A1 B1 C1 D1 E1 F1"
"ISPEXEC TBERASE "TEMP""
"ISPEXEC TBCREATE "TEMP" NAMES("COLUMNS") WRITE"
"ISPEXEC TBOPEN “TEMP" NOWRITE"
A1=AMD
"ISPEXEC TBSARG “TEMP" NEXT NAMECOND(A1,EQ)"
"ISPEXEC TBSCAN “TEMP""
"ISPEXEC TBADD "TEMP""
"ISPEXEC TBBOTTOM "TEMP""
"ISPEXEC TBCLOSE "TEMP""
"ISPEXEC TBOPEN "TEMP" NOWRITE"
"ISPEXEC TBDISPL "TEMP" PANEL(PANEL1)"
"ISPEXEC TBSKIP "TEMP"
"ISPEXEC TBCLOSE "TEMP""
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SkeletonsSkeletons
ISPF Skeleton services like generating JCLs from skeletons
Syntax is– ADDRESS ISPEXEC– “FTOPEN”– “FTINCL SKELNAME”– “FTCLOSE TEMP”– ADDRESS TSO– “SUBMIT ZTEMPF”
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File Tailoring Example:
/*REXX*/
"ISPEXEC LIBDEF ISPSLIB DATASET ID('PXX.XXX.SKEL') UNCOND"
PGM="IKEJFT01"
"ISPEXEC FTOPEN TEMP"
"ISPEXEC FTINCL PRAS"
"ISPEXEC FTCLOSE"
"ISPEXEC VGET (ZTEMPF)"
SAY ZTEMPF
"SUBMIT '"ZTEMPF"'"
EXIT
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File Tailoring Example:
Skeleton PRAS :
//SKELJCL JOB ('245T01',53),'SKELJCL',CLASS=T,
// MSGCLASS=T,REGION=0M,NOTIFY=&SYSUID
//*
//ISPF1 EXEC PGM=&PGM
//SYSPRINT DD SYSOUT=*
//SYSTSPRT DD SYSOUT=*
//SYSOUT DD SYSOUT=*
//SYSTSIN DD *
EX ‘XXX.XXX.REXX(MYREXX)'
//*
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ISREDIT Macros
Edit a dataset from program for required processing
Syntax is– ADDRESS ISPEXEC – "EDIT DATASET(‘XXX.XXX.XXX’)
MACRO(MYMACRO)"
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Macro Example:
/*REXX*/
ARG DSNAME1
ADDRESS ISPEXEC "EDIT DATASET('"DSNAME1"') MACRO(MACRO1)"
<< INSTRUCTION >>
<< INSTRUCTION >>
<< INSTRUCTION >>
EXIT
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Macro Example:
MACRO1/*REXX*/ ADDRESS ISPEXEC "ISREDIT MACRO" "ISREDIT FIND FIRST 'ENVIRONSYSTEM'" "ISREDIT X ALL ' ' 47 70 " "ISREDIT DEL ALL X" "ISREDIT C ALL ' ' 87 90 '****'" "ISREDIT SAVE" "ISREDIT END"
"ISREDIT MEND"
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Messages:
Pop messages to the panel Syntax is
– "SETMSG MSG(MSGXXnn) COND"
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Message Example
MYREXX:
MSG01:
"ISPEXEC LIBDEF ISPMLIB DATASET ID(“XXX.XXX.MESG") " If SYSDSN(PPP.PPP.PP) /= ‘OK’ THEN“ISPEXEC SETMSG MSG(MSG010A) “
MSG010A 'NO DATASET' .ALARM=YES ‘DATA SET IS NOT CATALOGUED ON THE DEVICE'
MSG010B 'NO MEMBER IN DATASET' .ALARM=YES ‘MEMBER NOT FOUND IN THE DATA SET ON THE DEVICE'
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LM FunctionsLM Functions
Dataset listMember list
– Copy members– Delete members– manipulate statistics of members
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LMDLIST - Example
/*REXX*/
LVL = USERID()
"ISPEXEC LMDINIT LISTID(ABC) LEVEL("LVL")"
"ISPEXEC LMDLIST LISTID("ABC") OPTION(SAVE) STATS(YES) GROUP(AMD)"
/* THE OUTPUT WILL BE IN HLQ.AMD.DATASETS*/
"ISPEXEC LMDFREE LISTID("ABC")"
EXIT
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LMMLIST - Example
/*REXX*/
DSN="‘XXX.XXX.LIST'"
"ISPEXEC LMINIT DATAID(ABC) DATASET("DSN") "
"ISPEXEC LMOPEN DATAID("ABC")"
"ISPEXEC LMMLIST DATAID("ABC") OPTION(SAVE) STATS(YES) GROUP(AMD)"
/* THE OUTPUT WILL BE IN HLQ.AMD.MEMBERS */
"ISPEXEC LMFREE DATAID("ABC")"
EXIT
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LMCOPY - Example
/*REXX*/ ARG DSNI DSNO ADDRESS TSO "ISPEXEC LMINIT DATASET('"DSNI"') DATAID(INP) ENQ(SHR)" "ISPEXEC LMINIT DATASET('"DSNO"') DATAID(OUT)
ENQ(EXCLU)" "ISPEXEC LMCOPY FROMID("INP") FROMMEM(MEM1) TODATAID("OUT") TOMEM(MEM2) REPLACE"
EXIT
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ReferencesReferences
TSO/E Version 2 REXX/MVS User’s GuideTSO/E Version 2 REXX/MVS ReferenceBoth these books are available on our file server
(IBM Book Manager for Windows)Programming in REXX by Charles Daney,
J.Ranade IBM series
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Thank You!
Thank You!