Using lint properly in Creator-Defined Statements?

[Aoide]

I'm currently trying to learn Creator-Defined Statements but I'm stumped as to how to use the lint statement properly. The renpy.error() statements I use never show up when there's a problem, and I can't figure out how to make it give an error when I want it to (eg. telling the user that "X is not a keyword argument or valid child for the statement." if they use a keyword argument for my statement that's not supported).

For example, if my statement is written as:

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my_statement "test1" param1 "value1" param2 "value2"

but "param2" is not a valid keyword I want to return the error:

Error: param2 is not a keyword argument or valid child for the my_statement statement.

Theoretically the lint statement should work something like this:

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def lint_my_statement(o):
	test1,kwargs = o
	
	e = my_error_checking(kwargs) # Returns "param2"
	if e is not None:
		renpy.error("Error: %s is not a keyword argument or valid child for the my_statement statement." %s)

But what do I need to do to get Ren'py to call it? (For what it's worth, the Example in the documents also doesn't seem to call the lint statement.)

Any help on this would be much appreciated because I want to make sure that my code handles errors properly. Thanks!

[PyTom]

You have to register it when you call register_statement.

[Aoide]

You mean like this?:

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renpy.register_statement("line", parse=parse_smartline, execute=execute_smartline, lint=lint_smartline)

Because that's how I registered it (using "lint=lint_my_statement"). Does it need to be registered in a different way?

[PyTom]

That should be it. Is lint getting called? I'd suggest having it unambiguously return an error. You can see examples of this working in renpy/common/000statements.rpy

[Aoide]

You mean something like this?

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def lint_my_statement(o):
   renpy.error("Return error when called.")

If so, it was one of the first things I tried it didn't give me any errors.

[PyTom]

That should register a statement. It works for me.

[Aoide]

I think I figured out the problem. For some reason I assumed the lint statement would error check every time the project was launched (like it does for Ren'py's native statements, such as when you write an invalid statement--like "grow" instead of "show"--or whatever), but it's only called by manually running the "Check Script (Lint)" command through the launcher. Sorry for making such a basic mistake... I gotta say I'm feeling pretty embarrassed right now.

Is there a way to route errors through the regular error checker like with coding errors (the error screen that comes up during the game and says things like "Parsing script failed." or "An exception has occurred.")? Or is it only able to go through the manually-run Lint check?

[PyTom]

I'm not sure. I'll check and see, since this seems like it would be a good thing to have.