require service { resource R; shared string question; shared int yes, no; const int WIDTH = 500; html NoVotes =

No one has voted yet!

; html Setup =

The Polling Service

What is the question: ? ; html Form =

The Polling Service

<[question]>?

Yes / No ; html Chart =

The Polling Service

<[question]>?
Yes

<[yes]>
No

<[no]> ; session New() { string q; show Setup receive[q = question]; writer (R) { question = q; yes = no = 0; } exit New vote started!; } session Display() { string q; int y,n; reader (R) { q = question; y = yes; n = no; } if (y+n==0) exit NoVotes; exit Chart <[question = q, yes = y, no = n, yes_ratio = (WIDTH*y)/(y+n), no_ratio = (WIDTH*n)/(y+n)]; } session Vote() { bool answer; show Form <[question = question] receive [answer = answer]; if (answer) yes++; else no++; Display(); } }