<h3>Constrained data types</h3>
<p>Declarations of variables other than local variables may be provided
with constraints. These constraints are not part of the underlying
data type for a variable, but determine error checking in the
transformed data, transformed parameter, and generated quantities
block, and the transform from unconstrained to constrained space in
the parameters block.</p>
<p>All of the basic data types other than <code>complex</code> may be given lower
and upper bounds using syntax such as