start page
~~~~~~~~~~

- login (uname pwd) -> start page (with error) / home page

- signup -> signup page


signup page
~~~~~~~~~~~

- signup -> signup page (with error) / start page (with success)


home page
~~~~~~~~~

- logout -> start page (with success)



PSEUDOCODE

login_page:
yield
if (login) continue login_vrfy:
if (signup) continue signup:

login_vrfy:
if (ok) continue home_page:
if (error) continue login_page: (with error)

home_page:
yield
if (logout) continue login_page: (with success)

signup_page:
yield
if (signup) continue signup_vrfy:

signup_vrfy:
if (ok) continue login_page: (with success)
if (error) continue signup_page: (with error)