Board with an embedded scheme interpreter

I've spent long nights meditating on this and I think I have a design that could work.

Commands are normal scheme expressions embedded in text, for example a post body of "Hello, number (+ 2 3)" would output "Hello, number 5". Literal parenthesis would need to be escaped with a backslash. All expressions are evaluated and their output displayed except for define expressions, which are both evaluated and displayed.

Each thread is roughly equivalent to a scheme session. Names defined in parent posts are available to subsequent posts in the thread. Names are immutable within a thread; symbols cannot be redefined.

Obviously a set of primitives should be provided: the basic arithmetic operations; a display operation; a set of formatting operations roughly equivalent in capability to today's BBCode; and, of course, our old friends cons, car and cudder.

What say you, /prog/? Can we do this thing?

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

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I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU

I ARE ANDRU