style system variables

[kaigou]

Is it possible to set a variable to be another variable?

That is, instead of:

set color_thing = "#333366";

doing:

set color_thing = $*some_other_thing;

such that the default value of $*color_thing is equal to the value of $*some_other_thing, but with option for user to override?

Comments

[zvi]

Yes, at the theme level, you can do that.

[kaigou]

It tells me: Can't reference a variable outside of a function. Can I create a temp-function just for the sake of this variable switch-out?

[branchandroot]

Right inside your print_stylesheet function, you should be able to require that variable x equal variable y. But that would screw with the ability of the user to select something totally different if that's what floats their boat. So I guess either you want to frame your x=y statement in such a way that if the values are changed they decouple, or else just set both variables to the same thing up in the settables list. *rueful* I usually go with the latter, despite it being longhand, as it were.

[kaigou]

Hmm. Unless it's something like:

if $x = "" { $x = $y } else { $x = $z }

...or something like that. I'm thinking back to the "leave blank for default" discussion elsewhere (per the wizard), and that if the user left the entry blank, then the default would prevail. In which case, the input -- $x -- would be = "" instead of = "user-input".

*ponders*

[zvi]

Hmm. Oh, you know, I've never actually tried to do it as a straight substitution. I've always done it through CSS, and you don't get the user over-riding them being connected that way.

thing-x { color: $*color-thing-y; }

Sorry for not thinking it through.

Um, I don't think you can temporarily define functions in themes? I know that you can create variables inside the print stylesheet functions, though. I don't know exactly how it's done, alas.

[kaigou]

I guess the question then becomes, can you set a value in a theme that then gets worked with on the layout level? Theme values override layout values, right? I mean, if in the base-layout it says something like:

set this_value = "200";

and then in the theme it says:

set this_value = "300";

the layout would take the latter and overwrite the former, correct?

[zvi]

Yes, that's true.

The thing that I don't think you can do, which I think you want to do, is say set this_value=y and in a function, set user_controlled_value=this_value

And then have there be an effect when the user changes the user_controlled_value through the wizard. I could be wrong about that, though.

[kaigou]

Yes and no. If I follow the logic, then currently it's something like this:

-- layout defines property $X
-- layout sets $X = 'blue' ---> default value
-- theme sets $X = 'green' ---> default value for theme
-- user sets $X = 'red' ---> overrides all of the above

Right? So if instead of setting $X in the theme, I define it in the layout like so:

-- layout defines property $X
-- layout defines property $Y
-- layout sets $X = 'blue' ---> default value
-- layout sets $Y = true
-- layout function sez:
... if $Y is true, $X = 'blue', else $X = $Z
-- theme sets $Y = false
-- theme sets $Z = green
-- user sets $X = 'red' ---> overrides all of the above by setting $Y as true and $X as red, theme value is ignored

... OR I could just say to hell with it and do it long-hand, because this is like spending twenty dollars to save ten cents, isn't it.

[afuna]

You can set properties to other properties on prop_init, but I'm not sure about the particular scenario you're proposing, since usually what we do is check whether $*Y has been set; if it has, we use the user-defined value. If it hasn't, we use the fallback value. So something like this:

layout:
property Color X { des = "base value" }
property Color Y { des = "falls back on base value if not provided" }
set X = "blue"
set Y = ""

function prop_init() {
    if ( $*Y == "" or not defined $*Y ) {
        # Y has no value, let's fill it in 
        $*Y = $*X
    }
}