<h2>Fun with Arithmetic</h2>


<!-- here's an example of evaluating a Tcl expression and using the result
immediately in the page (the = sign is the key) -->

<li>Two plus two is <%= [expr 2+2] %>

<li>This AOLserver is running version <%= [info tclversion] %> of Tcl.


# here's an example of escaping to Tcl  and executing code
# for its effect on the environment in which we'll evaluate the rest
# of the page

set aquarium_types_and_costs \
  [list [list "Lake Malawi Cichlid" 5000] \
        [list "Saltwater Community" 7000] \
        [list "Reef" 10000] \
        [list "Planted Freshwater" 6000] \
        [list "Suspended-in-midair Stingray Pond" 45000] \


<li>The first element of <code><%= $aquarium_types_and_costs %></code> is
<code><%= [lindex $aquarium_types_and_costs 0] %></code>


# we will use ns_puts to add to the viewable page from within this
# page

set costs ""
set total 0
foreach pair $aquarium_types_and_costs {
    # let's immediately destructure, preserving some
    # semblance of abstraction
    set aquarium_type [lindex $pair 0]
    set aquarium_cost [lindex $pair 1]
    incr total $aquarium_cost
    append costs "<li>$aquarium_type will cost \$$aquarium_cost\n"

append costs "<p>\n<li>Total:  \$$total"

<li>Here are some aquarium plans for the new building:
<%= $costs  %>