Well, are you aware that the same Haskell you cite has a REPL environment, with on the fly code patching, and that does not require all expressions to "go throught main" anyway, right?

I simply have no idea how anyone would use a REPL to do main development (I never liked the idea anyway). I use it just for early stage testing and debugging assistance, just like I do in Python, Lisp, Prolog... and certainly not Perl - this one has a useless REPL.