Check if evaluated values are the same

[mhspelt]

Hi, is it possible to use cond or choose to check whether two values are the same?
I tried the following but it does not work:

var data = new { 
	x = 3,
	y = 3
};

// Print "is on the line" iff data.x == data.y:
Console.WriteLine(Smart.Format("The point ({x}, {y}) {x:choose({y}):is|is not} on the line y = x", data));
Console.WriteLine(Smart.Format("The point ({x}, {y}) {x:cond:={y}?is|is not} on the line y = x", data));

It seems that {y} is not getting substituted before the choose or cond is evaluated. Would be great if there is a standard way to do it that I've been missing.

Fiddle: https://dotnetfiddle.net/08nHRw

[axunonb]

Hi @mhspelt
Yes, you are right, the comparison currently requires a literal. A placeholder does not work.

A fix could format with an additional parameter with equality:
Fiddle: https://dotnetfiddle.net/OjHoRj
Did you find a better solution?

Evaluating Placeholders would be a nice improvement, though. The Format from the Parseralready returns all Placeholders. The ConditionalFormatter however assumes that child Formats in the parameters are not nested. It should rather make sure and throw for nested parameters.

A PR for allowing Placeholders would be great ;-)

[mhspelt]

I had a look at the code, but it seems that this would require quite a big change. For one, the parser needs to be made really recursive -- now the choose option thinks that you are trying to format x with the formatter choose({y. I'll just use the workaround with the boolean parameter for now.

[axunonb]

True, after having a deeper look: quite a change. And also hard to distinguish which placeholders should be evaluated at which time, given that placeholders can be nested. I tend to leave such complex logical extensions out of the project. If this is needed, Scriban is a better choice (though not as simple to use as SmartFormat).