error message for size()

[shiffman]

I believe there are several issues related to friendly error messages like #717 and #657, however, I couldn't find the right place for this. Someone feel free to move and close if a new issue isn't appropriate.

I was teaching a short workshop yesterday for some students who knew Processing. I ran the following code:

function setup() {
  size(200, 200);
}

function draw() {
  background(0);
}

And showed them the message: Uncaught size() not implemented, see createCanvas(). No one was able to guess what this meant, I propose changing it to something a bit more explicit? I'm terrible at writing these, but something along the lines of size() is not a valid p5 function, to create a drawing window please use createCanvas() instead.

[workergnome]

I think that would be very helpful. Some more documentation on how to use the friendly error handling would be great—it's a fantastic tool, but I also am not 100% sure how to work with it. @crecord or @crhallberg, is there a place where people like myself could learn more about how to use it?

Thanks!

[workergnome]

Looking into this a little bit—is there any reason why we don't just make size() function call the createCanvas() function? We could still throw a depreciated method note in there, but it seems pretty obvious what the user is intending...

Apologies if this was already discussed somewhere earlier.

[lmccart]

@OhJia are you still interested in working on this one?

[OhJia]

@lmccart updated error message and sent PR