The mainframe is, by definition, iron. IRON MAIN is a packaged set of utilities to make Emacs usable to edit files -- ahem, datasets -- and minimally interact with a mainframe.
The mainframe is, for the time being, an IBM architecture machine (or an emulator - see below) running a variant of MVS or z/OS.
Some motivation: as of Winter 2023 (since Fall 2020), there appeared to
be no Job Control Language (JCL)
mode (that is, a jcl-mode) floating around the Emacs Internet world.
Probably there was no need for it. Yet. So it seemed to be a good
idea to write one.
The result is this minimal collection of tools and modes in Emacs Lisp to interact with the mainframe.
IRON MAIN comprises the following:
- pl1-mode (file
pl1-mode.el): a major mode to handle PL/I code (see file for more information, history and credits). - hlasm-mode (file
hlasm-mode.el): a major mode to handle IBM Assemblers, at least in their barebone forms (with minimal support for HLASM. - jcl-mode (file
jcl-mode.el): a major mode to handle IBM MVS or Z/OS JCL. - jcl-poly-mode (file
jcl-poly-mode.el): a major mode to handle IBM MVS or Z/OS JCL based on `polymode.el'; PL/I, COBOL, Fortran and ASM are supported as inner modes.
Some tweaking was done to ensure that the column tracking and the
ruler (cfr., ruler-mode) that is used in the various editing modes
are 1-based, as expected on a "card".
The code has been tested with MVS 3.8j TK4- and MVS 3.8j "Jay Moseley" build, running on a Hercules (SDL/Hyperion 4.2.x). Useful links follow.
- IBM z/OS: https://www.ibm.com/it-infrastructure/z/zos
- Hercules: http://www.hercules-390.eu/
- SDL/Hyperion: https://github.com/SDL-Hercules-390
- TK4-: http://wotho.ethz.ch/tk4-/
- Jay Moseley's site: http://www.jaymoseley.com/hercules/ (and other useful things).
- IBM Assemblers: https://en.wikipedia.org/wiki/IBM_Basic_Assembly_Language_and_successors
jcl-mode and jcl-poly-mode are major modes to handle IBM MVS or Z/OS JCL.
The basic "grammar" of JCL is the following, "line-oriented" one:
//<name>? <operation> <operands> <comments>
or
//*<comment>
everything starting at the // or //* and ending at the end of
line, or better at the 72nd column with whitespaces meaningful.
Actually, we are not even talking about "lines", but we are
talking about "cards" (as it should be).
In the following the naming just follows the above convention.
The mode, for the time being, allows you to write JCL files, pardon, "data sets", using Emacs editing facilities, plus two useful facilities.
The mode defines also two useful functions to "submit" your JCL to a running instance of MVS or Z/OS, provided that
- Your MVS or z/OS has a "card reader" listening on a port (default 3505).
- You have the necessary credentials to run the job on the OS.
The two functions (which are available on the Emacs menubar) are
jcl-submit (alias submit; Emacs and ELisp do not define this
as a function) and jcl-submit-file (a misnomer; it should be
"jcl-submit-dataset"). The two functions submit either the
current buffer or a file of your choice to the "card reader".
Files with .jcl extensions are opened in jcl-mode. `jcl-poly-mode'
can be entered by invoking the eponimous function.
Most behavior is customizable in the "jcl" group.
If you manually downloaded the package, you can open the
testsubmit.jcl file, which just executes IEFBR14 and
allocates a dataset, and submit it to your MVS or z/OS
instance.
hlasm-mode is a major mode to handle Assembler/IBM MVS or z/OS High Level ASM IBM. The mode just does highlighting and some minor indentation, plus flagging of bad continuation lines. It tries to be somewhat smart about strings, "attributed" symbols and expressions and comments.
It is different from the "standard" Emacs assembler mode because of some syntax peculiarities that required some special treatment for Font Lock Mode.
More functionalities may come in the future.
pl1-mode is a major mode to handle PL/I code. The mode just does highlighting and some minor indentation. Syntax recognized is quite limited, but most statements and attributes are properly highlighted.
More functionalities may come in the future.
To use the package, just install the folder iron-main in your Emacs
setup and ensure that the file iron-main.el is loaded. Files with
.jcl extension will now load in jcl-mode.
Of course you are free to fork the project subject to the current licensing scheme. However, before you do so, I ask you to consider plain old "cooperation" by asking me to become a developer. It helps keeping the entropy level at an acceptable level.
Enjoy
Marco Antoniotti, Milan, Italy, (c) 2020-2023