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, 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
    }
}