dummy-proof it.

Signed-off-by: AJ Rossini <blindglobe@gmail.com>
removed the length and compile directives, since renamed to lengthv for ease of use (at expense of sub-optimal name)

Signed-off-by: AJ Rossini <blindglobe@gmail.com>
moved data structure overview from example to README


Signed-off-by: AJ Rossini <blindglobe@gmail.com>
error checked for proper variable names.
included unit-test and examples for this.
example.lisp: df is now df-1

Signed-off-by: AJ Rossini <blindglobe@gmail.com>