I donä't get while-loops

[ssecorp]

in read2 it never quits when I write quit, why?

def read():
    expr = raw_input("Lisp> ")
    if expr != "quit":
        print parse(expr)
        read()
    else:
        print "Good session!"

def read2():
    expr = ""
    while expr != "quit":
        expr = raw_input("Lisp> ")
        print parse(expr)
        read2()
    print "Good session!"