aint &#39;[&#39; expression &#39;,&#39; expression &#39;]&#39;
           | &#39;cholesky_factor_corr&#39; &#39;[&#39; expression &#39;]&#39;
           | &#39;cholesky_factor_cov&#39; &#39;[&#39; expression ?(&#39;,&#39; expression) &#39;]&#39;
           | &#39;corr_matrix&#39; &#39;[&#39; expression &#39;]&#39;
           | &#39;cov_matrix&#39; &#39;[&#39; expression &#39;]&#39;

constraint ::= range_constraint | &#39;&lt;&#39; offset_multiplier &#39;&gt;&#39;)

range_constraint ::= ?(&#39;&lt;&#39; rang