Post by fourmisant in Lil Programming Questions

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Hi! In this post, you mentioned that:

If we wanted clicking on chester to toggle frobnicate, we'd write a script for him like so:

on click do
 home.widgets.frobnicate.value:!home.widgets.frobnicate.value
end

Or, to be a bit less repetitive,

on click do
 f:home.widgets.frobnicate 
 f.value:!f.value
end

It seems that in this case, assigning to `f.value` actually modifies `home.widgets.frobnicate`.

However, when running this in the Listener:

x.a:1 x.b:2 x.c:3
show[x] # {"a":1,"b":2,"c":3}
y:x y.a:42
show[y] # {"a":42,"b":2,"c":3}
show[x] # {"a":1,"b":2,"c":3} still the same!

The behavior is different, `y.a:42` doesn't modify `x`.

Could you explain why?

Internet Janitor130 days ago(+2)

The difference is that deck parts are "Interface" values, while your later example is a dictionary.

Lil's basic datatypes (numbers, strings, lists, dictionaries, tables, functions) are all immutable values: attempting to modify them will return a new value and leave the original value unchanged.

Interfaces (like most deck parts) are mutable, and accessing or modifying their attributes may have side-effects. For example, modifying the ".index" attribute of a widget to change its order on a card will also visibly modify the ".widgets" property of the container card, since these attributes are related to one another. The "sys" interface exposes "sys.now", an attribute which contains the current Unix timestamp, and may (generally) be different every time it's accessed. Lil also offers utility Interfaces like Array for those times when mutable data structures are necessary for performance reasons.

Does that make sense?

fourmisant129 days ago

Thanks for the quick response! Initially, I thought this might be that `home.widgets.frobnicate` is copied by reference, now I see that Interface values are more to this. They look more like modifiable "values" instead of "variable names", and after assigning them to a name, making changes to the attributes under that name actually interacts with the "value" instead of replacing it with a new one.

itch.io

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