 (regerror res rg)))
    (set! res (regexec rg "The color green" 1 0))
    (display res) (newline)                ; #i(4 9) = match start/end
    (regfree rg)))
</pre>
</div>


<div class="indented" id="libgsl">
<pre>
(require libgsl.scm)

(define (eigenvalues M)
  (with-let (sublet *libgsl* :M M)
    (let* ((len (sqrt (length M)))
	   (gm (gsl_matrix_alloc len len))
	   (m (float-vector-&gt;gsl_matrix M gm))
	   (evl (gsl_vector_complex_alloc len))
	   (evc (gsl_matrix_complex_alloc len len))
	   (w (gsl_e