irule for URI based redirection to separate Pools

You can find a good documentation of iRule events tips and tricks in this link: https://devcentral.f5.com/articles/irules-101-04-switch

I will try to be clear, here we go:

 This event triggers in http request
when HTTP_REQUEST {
     this will store the first http path segment in lower case
     so, we'll define the request traffic direction as needed
     example:
     request for url: http://mywebservice.com/DEV/service
     [HTTP::host] ==> mywebservice.com (not used, just to understand)
     [HTTP::path] ==> /DEV/service
     [split [HTTP::path] "/"] ==> [split /DEV/service "/"] ==> { DEV service}
     [lindex { DEV service} 1] ==> DEV
     [string tolower {DEV}] ==> dev (this is useful when web service is case insensitive (windows eg))
     set path ==> stores the value "dev"
    set path [string tolower [lindex [split [HTTP::path] "/"] 1]]


     this will verify the value stored in path variable
    switch -glob $path {
         case value is "dev", request goes to the pool-dev
        "dev" { pool pool-dev }

         case value is "ct", request goes to the pool-ct
        "ct" { pool pool-ct }

         case value is "uat", request goes to the pool-uat
        "uat" { pool pool-uat }

         otherwise, show the help page
        default {
             here we will write the response content page
            HTTP::respond 200 content "`Available resource options````