Lawson 4GL is basically MicroFocus Cobol. Lawson made a few tweaks to the compiler so it is not vanilla MF Cobol. It should be available on your install definition. If not, you should contact your account rep to get it to you. There really is no documentation for the product other than some basic manuals that you can download from their support site.

It's a little more than just tweaks to the compiler; it's the programming environment in which Lawson's programs were originally developed, including the ability to share program code (libraries), define database tables, work files, screens, reports, etc. and generate the artifacts that are pre-compiled into a complete .cbl program that is then ultimately compiled by Micro Focus' compiler. The MF compiler is NOT a custom one-off version for use with Lawson. If you want to read more, you should consult the Lawson documentation entitled (I think) development workbench and workbench standards.