Make a Shlaer-Mellor Executable UML Model Repository

This is the first step in the model execution tool chain.

The make-xuml-repo command generates an empty metamodel database that can be populated with the modeled components of your system.

We say 'metamodel' because the generated database schema defines the Shlaer-Mellor Executable UML modeling language. It defines all structures necessary to describe platform independent domains, class models, state models, as well as the complete computational activities driven by each state transition and method call.

Output

The output consists of these three files:

• mmdb.ral -- The database
• mmdb.txt -- Human readable text that displays all of the database tables (relvars / relational variables)
• mmclass_nt.py -- A set of python named tuples, one per metamodel class, used for model population. Each metamodel class corresponds to a similarly named relvar (table).

Input

The input to make-xuml-repo is a set of *.xcm (Executable Class Model) files. The files are parsed using the xcm-parser. You can view these files here in the metamodel folder. The sibling layout folder has a set of diagrams generated by flatland you can view.

This file set defines a subset of the full modeling language though the bulk of the language is, in fact, supported. But work continues and, as the .xcm files upgrade, it will be necessary to refresh your metamodel database by re-running make-xuml-repo.

Go to the Shlaer-Mellor Metamodel Wiki for the complete (and not yet fully implemented) model set and model documentation. What is actually implemented, though, is maintained here in the make-xuml-repo repository.

Database

Rather than a traditional SQL database, we use Andrew Mangogna's open source TclRAL (Tcl Relational Algebra Library).

It is an implementation of relational algebra as defined by C.J. Date and Hugh Darwen. So we can use nested relational algebra without any of that SQL mess. It is implemented in C and Tcl, but we provide a python front end called PyRAL to keep everything pythonic.

Installation

Create or activate a Python 3.11–3.13 environment, then install from PyPI:

% pip install make-xuml-repo

Note: Python 3.14 is not yet supported. Its bundled Tcl/Tk 9.0 is incompatible with the TclRAL engine that PyRAL relies on, so use Python 3.13 or earlier.

It's a good idea to upgrade pip first if you haven't in a while:

% pip install --upgrade pip

Once installed, you can invoke the repository generator with the makexumlrepo command.

Usage

Run the command in the directory where you want the output files created:

% makexumlrepo

This generates three files in the current directory:

• mmdb.ral — The database. Although it is a text file, it can be opened by TclRAL (via PyRAL) to establish an empty relvar (table) per metamodel class, ready to be populated with instances of your modeled domains.
• mmdb.txt — A human readable listing of every relvar in the database.
• mmclass_nt.py — A set of Python named tuples, one per metamodel class, with a field for each of that class's attributes. PyRAL uses these to insert one or more tuples into the corresponding relvar.

You can load these with the metamodel populator (coming soon) or your own tooling. In my own workflow I generate the files and copy them into my metamodel populator package.

Command line options

Option	Long form	Description
-h	--help	Show a summary of all options and exit.
-V	--version	Print the installed version and exit.
-M	--models	Copy the packaged metamodel and layout directories into the current directory, then exit. Existing directories are left untouched (a warning is issued). No database is built.
-v	--verbose	Show warnings on the console. By default warnings are suppressed on the console (but still recorded in the log file when -L is used).
-L	--log	Keep the diagnostic make_xuml_repo.log file. Without this flag the log is removed on exit.
-D	--debug	Run in debug mode.

Inspecting or customizing the metamodel

If you want to look at the .xcm metamodel files or the layout sheets that ship with the package, copy them into your working directory with:

% makexumlrepo -M

This creates a metamodel directory (the .xcm files and mm_types.yaml) and a layout directory in the current directory. No database is generated when -M is supplied.