by H. Fosdick © 2024 RexxInfo.org CC: BY-ND
These charts enumerate equivalences between Rexx and Clist. They're for those who know one of these languages and want to learn the other. They may also be useful for conversions. (These charts are not about "which language is better".) Click here for PDF version.
| Rexx | CLIST | |
|---|---|---|
| Easy to learn, use, and maintain | Yes | Yes |
| Very powerful | Yes | No (lacks common language features) |
| Open source | Yes | No |
| Portable | Yes | No |
| Runs on all platforms | Yes | No |
| Runs as the mainframe Shell | No | Yes |
| Interfaces to tons of tools | Yes | No (intended to issue OS commands) |
| ANSI or ISO Standard | Yes (ANSI-1996) | No |
| Rexx | CLIST | |
|---|---|---|
| Dialects | TRL-2, ANSI, Mainframe, ooRexx, NetRexx | CLIST |
| Unique Usage | * Default scripting language for mainframes and several minor platforms
* Interfaces to all mainframe environments and address spaces |
* Available on all z/OS mainframes |
| Programming paradigms | Procedural, scripting, object-oriented (ooRexx and NetRexx), functional | Procedural, scripting |
| OOP: classes, objects, multi-inheritance, polymorphism, encapsulation | In ooRexx and NetRexx | Unsupported |
| User Group | Rexx Language Association | SHARE |
| Quick Online Lookup | Quick Lookup | IBM TSO CLISTs Manual |
| Cheat Sheet (printable PDF) | ANSI Rexx, Mainframe Rexx | Only this one |
| Forum | RexxLA forum | Expert Forum @ IBMMainframes.com |
| Further information | RexxInfo.org | IBM TSO CLISTs Manual |
| ANSI Rexx | CLIST | |
|---|---|---|
| Format | Free form | Free form |
| Case-sensitive | No | Yes |
| Variable Names | Valid Symbol that does not start with a digit (0-9) or a period (.), | Start with & Next character must be one of: A-Z, (a-z), _, #, $, @ |
| Comments | Enclose inside /* and */ | Enclose inside /* and */. Or put comment at end of a line by starting it with /* |
| Line Continuation | , (comma) | - (minus sign) or + (plus sign) |
| Statement Separator | ; (semi-colon) | None (implied by line end) |
| Code Blocks | Define by do - end | DO-END, SELECT-END (Also DATA-ENDDATA, DATA PROMPT-ENDDATA) |
| Undefined Variables | Allowed. Use SYMBOL to determine if a variable has been defined | Allowed until misused |
| Assignment Operators | = | SET = |
| Arithmetic Operators | + - * / % ** // | + - * / ** // |
| Comparison Operators | == \== >> << >>= \<<
<<= \>> = \= <> ><
> < >= \< <= \>
( \ can be replaced with ¬ in any of these) |
= EQ ¬= NE < LT > GT <= LE >= GE ¬> NG ¬< NL |
| Logical Operators | & | && \ (prefix) ¬ (prefix) | AND && OR | |
| Concatenation Operators | || Or, concatenate with blank between Or, concatenate by abuttal (no blank) |
By abuttal: SET VARIABLE=&VAR1&VAR2 |
| Bitwise Operators | Use built-in functions | Unsupported |
| Membership Operators | Unsupported | Unsupported |
| Regular Expressions | Use RexxRE Regular Expressions external Library | Unsupported |
| String Parsing | PARSE instruction | A few string functions |
| Built-in Functions | About 70 functions | 15 functions, plus about 55 Control Variables |
| Data Types | Everything's a string, types are reflected in usage | Defined by usage |
| Function to Check Data Type | datatype | &DATATYPE |
| Collections of Variables | Use compound variables | Unsupported, you would have to program this |
| Associative Arrays | Use compound variables | Unsupported |
| Multidimensional Arrays | Use compound variables | Unsupported |
| Stack & Queue Operations | Yes (push, pull, parse pull, queue, queued) | Unsupported as a generalized feature, but can manage the terminal input buffer as a stack |
| Decimal Arithmetic | Default | Unsupported |
| Flow of Control | if, do, select, call, exit, return, iterate, leave, signal, nop | IF-THEN-ELSE, DO, SELECT, GOTO, EXIT, RETURN, SYSCALL, ATTN, ERROR, TERMIN, TERMING |
| GOTO | none (use signal) | GOTO |
| Calling Subroutine | call | SYSCALL |
| Manage Scope of Variables to Subroutines | procedure expose | Use PROC |
| Subroutine End | return | END |
| Getting Return Code | special variable RC RESULT set by subroutine RETURN | &LASTCC, &MAXCC for highest return code set |
| Trace Script Execution | trace (instruction), trace (function) | Use CONTROL statement |
| Show Full Execution | trace a | CONTROL LIST |
| Exception Handling | signal | ERROR, ATTN |
| Standard Exceptions | novalue, error, failure, halt, notready, syntax, lostdigits | ATTN (attention key pressed), ERROR (traps any of more than 100 error conditions) |
| Attention Routines | signal on halt | ATTN |
| Run an Operating System Command | Just issue the command string (Rexx passes unrecognized strings to the default active environment) | Just issue the command |
| Terminate Process | exit | EXIT |
| End with Return Code | exit 8 | EXIT(8) |
| Get User Input | say "Enter your name:" parse pull name | WRITE Enter your name: READ NAME |
| Read Input Record | linein execio (mainframe only, not ANSI) | GETFILE |
| Write Output Record | lineout execio (mainframe only, not ANSI) | PUTFILE |
| Write without line feed | Unsupported | WRITENR |
| Get Date and Time | date and time functions | &SYSDATE, &SYSTIME |
| Get Length of a String | length("MYSTRING") | &LENGTH(MYSTRING) |
| Get a Substring | substr("MYSTRING",1,4) | &SUBSTR(1:4,MYSTRING) |
Based on Rexx Programmer's Reference and IBM TSO CLISTs Manual. Also z/OS TSO/E REXX User's Guide compares Rexx with Clists.
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