CLIST (Command List; pronounced "C-List") is a procedural programming language for Time Sharing Option (TSO) in SVS and MVS systems. It originated in OS/360[1] Release 20 and has assumed a secondary role since the availability of Rexx in TSO/E Version 2. In its basic form, a CLIST program is a list of commands to be executed in strict sequence (like a DOS batch file (*.bat) file). OS/VS2 R3.6 (MVS) added If-Then-Else logic and loop constructs to CLIST.[2] The term CLIST is also used for command lists written by users of NetView.[3]
CLIST is an interpreted language. That is, the computer must translate a CLIST every time the program is executed. CLISTs therefore tend to be slower than programs written in compiled languages such as COBOL, FORTRAN, or PL/1. (A program written in a compiled language is translated once to create a "load module" or executable.)
CLIST can read/write MVS files and read/write from/to a TSO terminal. It can read parameters from the caller and also features a function to hold global variables and pass them between CLISTs. A CLIST can also call an MVS application program (written in COBOL or PL/I, for example). CLISTs can be run in background. CLISTs can display TSO I/O screens and menus by using ISPF dialog services.
Compare the function of CLIST with that provided by REXX.
Adding If-Then-Else logic:
