Turning a function into a creator-defined statement

[rezaf]

I'm trying to steamline the code in my current WIP project.
One thing I'd like to change if possible is swap "$ xyz" calls with direct calls without Python, and from how I understand the documentation, Creator-defined statements seem like the way to go.

Simplest example:
$ showScene("myScene")

This calls a simple python function.

Code: Select all

def showScene(scenePicture, clearActors=True):
renpy.scene()
renpy.show(scenePicture)
(...)

Now, I'd like to be able to just write "showScene myScene", that'd look much slicker in code.
I tried to go by the description/example given in the documentation and ended up with this here:

Code: Select all

python early:

    def parse_showScene(lex):
        what = lex.simple_expression()
        return what

    def execute_showScene(o):
        what = o
        renpy.scene()
        renpy.show(what)

    def lint_showScene(o):
        what = o
        try:
            eval(what)
        except:
            renpy.error("Scene not defined: %s" % what)

    renpy.register_statement("showScene", parse=parse_showScene, execute=execute_showScene, lint=lint_showScene)

Okay, when you're done facepalming, maybe you can show me how it ought to be done?
Cause OBVIOUSLY that doesn't work and I get an "expected statement" error instead.
The code compiles if I write >showScene "myScene"< instead, i.e. put myScene in quotes, but then all hell breaks loose if I actually get to that point.

Thanks you very much in advance.

[hell_oh_world]

I'm not sure why do you need that function in the first place, clearly your function can be achieved by doing something like this...

Code: Select all

label start:
    scene the_image # this clears the screen and show at the same time a new image, this is the exact equivalent of that in your function.

[rezaf]

Obviously the showScene should do additional things instead of just showing the scene, hence the (...)

[hell_oh_world]

Still doesn't make sense, as your function only requires one parameter. I wouldn't bother creating one just for this. Maybe if you have multiple parameters that can be split into multiple lines then that's the time to use creator defined statements. Typing `$ showScene("something")` it's not really laborious at all...

[isobellesophia]

I don't know python but, what do you mean by additional things from the image? Maybe you were talking about screen on the image, imagemaps... or interactive things maybe? Point and click? Movie?

Adding a block simply from the image can do positioning the image itself like xpos... linear... and more style functions from the code itself.

[gas]

Write the thing in a script called something like '01mystates.rpy'.
And recompile the game.

[rezaf]

Heh, my question was not whether or not people thought it was a sensible thing to change this into a creator-defined statement, I asked how to do it.

I understand how to write calls with $ in front, as I mentioned in the first post, and I also wrote this was the simplest example, my intention there is to learn how to use this feature and then to use it several times.

As for the additional things, I currently have my own jury-rigged actor subsystem, and when I open up a new scene I'd like that to be automatically cleared. There's another system I haven't fully implemented that I might want to affect here as well. That's it, mostly.
The actor system itself is a little more complicated and comes with more parameters, I'd like to reimplement this as well, if possible.

@gas: Sure that this will affect anything? I'll give it a try tomorrow ...

[gas]

@gas: Sure that this will affect anything? I'll give it a try tomorrow ...

From the same docs:

Creator-defined statements must be defined in a python early block. What's more, the filename containing the user-defined statement must be be loaded earlier than any file that uses it. Since Ren'Py loads files in Unicode sort order, it generally makes sense to prefix the name of any file containing a user-defined statement with 01, or some other small number.

A creator-defined statement cannot be used in the file in which it is defined.

[philat]

The reason everyone is saying maybe don't do it is because it's time and effort going into something with not a ton of benefit -- the difference in effort between $showScene(myScene) and showScene myScene is... negligible. The effort of getting a creator-defined statement to work is less negligible (unless you already understand how the lexer works, which frankly, I don't, and I took a stab myself at several creator-defined statements for the sake of learning) and that effort increases as you add more functionality to the statement (like, do you want to optionally include that clearActors=True/False part? Have fun figuring out dealing with that in the lexer).

That said, your example works if you do what gas tells you to, but it won't show an image with tags correctly -- if you write showScene bg room, it will clear the screen and show the image bg (not bg room).

[rezaf]

(snip)

Yeah, that did indeed work. You know your stuff, thank's a bunch indeed.

@philat: Maybe you're right, but I'm still glad I at least go this simple statement to work. It's a start.
As for the clearActors thing, maybe I can just define a showSceneClear which does that, then it won't need another parameter.
We'll see, I'll try to play around with this some more asap.

Thanks again everyone.

[rezaf]

@philat: Getting the clearActors to work turned out to be quite simple, I just had to use an integer instead of a boolean because the lexer doesn't appear to support bools.

[drKlauz]

You can also hook scene/show statements:
https://www.renpy.org/doc/html/config.h ... nfig.scene
https://www.renpy.org/doc/html/config.h ... onfig.show
This will allow adding extra functionality without adding new statements and might be simpler way, depending what was hidden by (...) in first post.