CLIST

CLIST (Command List) (pronounced “C-List”) is a procedural programming language for TSO in MVS systems.

It originated in OS/360 Release 20 and has assumed a secondary role since the availability of Rexx in TSO/E Version 2.

The term CLIST is also used for command lists written by users of NetView.In its basic form, a CLIST program (or “CLIST” for short) can take the form of a simple list of commands to be executed in strict sequence (like a DOS batch file (*.bat) file).

However, CLIST also features If-Then-Else logic as well as loop constructs.

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 (by running JCL which executes the TSO control program (IKJEFT01)).

TSO I/O screens and menus using ISPF dialog services can be displayed by CLISTs. Compare the function of CLIST with that provided by REXX.