How can I run Alloy in command line?

I have version 6.1.0.202111031525 which, as I understand, is fairly recent.

Unfortunately I must say that the GUI is not suitable for me. I have a finely tuned emacs installation that I should rather edit my Alloy code with. I can then open a file in Alloy’s GUI and press some buttons to make it check my models — but this is far from an ideal working environment.

With other languages, I can write a one line shell script that watches for changes in my source code and runs the compiler automatically every time I save my project. I should like to have a similar arrangement with Alloy. How can I achieve it? Ideally I should like for Alloy to check the model, print the instances and also save their graph representations to files that I can view with a viewer of my choice.

I see that there are some command line possibilities:

% alloy --help --quit
Usage: alloy [options] file ...
  //  -d/--debug                  set debug mode
  -h/--help                   show this help
  -q/--quit                   do not continue with GUI
  -v/--version                show version

So, I can do like this:

% alloy --quit example.als

— But this does not seem to do anything. Truly it will exit successfully even if I give it a random file. It does not even check the syntax!

Here are two ways of integrating scripts with Alloy without writing any new Java code.

#1 There are some other classes in the Alloy jar that expose a main method that might be useful. Here’s an example of abusing the ExampleCompilingFromSource class to evaluate a model that has been packed into a single command line argument:

$ java -cp org.alloytools.alloy.dist.jar edu.mit.csail.sdg.alloy4whole.ExampleCompilingFromSource "sig Room {link: set Room } {#link < 4} fact { some home:Room | home.*link = Room } run {} for exactly 5 Room"

#2 You can use Alloy’s Java APIs directly from scripting languages using a foreign function interface library. Here’s an example of calling into the Alloy jar from Python using JPype:

Alloy from Python is just what I needed.

Thank You!

Evelyn Mitchell