Refactor if-chains, add to janet

[MichalMarsalek]

1 more point from #328

[MeWhenI]

Janet could also use cond for implementing ConditionalOp, and I imagine some other langs might also be able to pull the IfChain logic over to conditionals.

[MichalMarsalek]

Ah, right. It might make sense to merge the two (If and ConditionalOp) completely, but for now, I just used the logic for ConditionalOp too.

[MeWhenI]

Is there a plugin that currently exists to try inverting the condition and then swapping the alternate and consequent statements? Since if-chaining as I understand it only expands the alternate, this would be beneficial. Maybe thats for a separate issue though, PR otherwise looks good.

[MichalMarsalek]

Is there a plugin that currently exists to try inverting the condition and then swapping the alternate and consequent statements? Since if-chaining as I understand it only expands the alternate, this would be beneficial. Maybe thats for a separate issue though, PR otherwise looks good.

Such plugin should probably be added, but I wonder if there's ever a reason to nest the conditions in a "nonstandard" way in the Polygolf program?

[MeWhenI]

What do you mean by "nonstandard" nesting?

[MichalMarsalek]

What do you mean by "nonstandard" nesting?

One that is not

if(cond){

}
else{
  if (cond){

  }
  else{
    if(cond){
    
    }
    else{
      
    }
  }
}