simple if statements optimized to switch statements ?

I think you can pull two rules of thumb from the above:

• It's always better to use fewer variables if possible. Variables take up additional memory. So the following:

  set path_lower [string tolower [HTTP::path]]
  if { ( path_lower eq "somepage.html" ) || ( path_lower eq "anotherpage.html" ) } {
      pool mypool-01
  }
  

  would be better like this:

  if { ( [string tolower [HTTP::path]] eq "somepage.html" ) || ( [string tolower [HTTP::path]] eq "anotherpage.html" ) } {
      pool mypool-01
  }
  

• A switch is generally more efficient than an if, but the difference would likely be negligible for a small set of evaluations. You'll also find that an if is usually more flexible than a switch. A switch can, at the most, evaluate wildcards with a -glob option, while an if can evaluate regular expressions and beyond. All of that said, I would still probably opt for a switch, when possible, when I have at least two or more evaluations to perform.

I'm surprised it's more optimal to evaluate an expression each time rather storing the result in a variable

 

The thing is, you're not performing an evaluation with these protocol commands (ie. [HTTP::path]). The information is already stored in the state table for this request, so [HTTP::path] is itself a variable, more or less.

 

in EXAMPLE 2 , because two comparisons are performed you'd prefer a switch over an if ?

 

You can really go either way with 1 to 10 comparisons, but I think anything more than that just turns into confusing code. It's a matter of preference more than performance.

 

What I'm referring to is performing the [string tolower] operation multiple times

 

Good point, and another good reason to use a switch since it's only done once.