am I missing the way to return computed values as variable values

[pm100]

I would like to expose variables (not functions) to the expressions that are not simple data items but I cannot find a way to do it .

Specifically - I am writing a 6502 emulator debugger. I want to expose the registers as variables in expressions. I can find no way to do it because of this signature:

fn get_value(&self, identifier: &str) -> Option<&Value>;

In the Context trait. It requires me to return a reference to a Value, if the value is looked up or computed in any way I cannot do that. I note that :

fn call_function(&self, identifier: &str, argument: &Value) -> EvalexprResult<Value>

returns the actual value not a reference. It would be a lot simpler if get_value did the same.. Is there some magic trick I am missing

[ISibboI]

There was #104 that may solve this, but it is outdated and stale. Feel free to make a new one, but I don't have much time to review or merge at the moment.

[pm100]

I see that bug / PR - two questions

• why return a Cow, why not a simple value just like call_functions does
• it seems you dont mind a breaking change, this would require a change to the Context trait

[ISibboI]

Cow because the value may be borrowed or a value. In case of a context that stores values as they are, cloning them every time they are read is wasteful.

Breaking changes are fine.

On Thu, 4 Jan 2024, 3.25 pm100, @.***> wrote:

I see that bug / PR - two questions

• why return a Cow, why not a simple value just like call_functions does
• it seems you dont mind a breaking change, this would require a change to the Context trait

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