"subsection"> 63.1.1 Plain-text input and output </h3>

<p>In plain-text input and output,
it is assumed that each item to read or write is an atom:
an integer, float, bigfloat, string, or symbol,
and not a rational or complex number or any other kind of nonatomic expression.
The <code>numericalio</code> functions may attempt to do something sensible faced with nonatomic expressions,
but the results are not specified here and subject to change.
</p>
<p>Atoms in both input and output files have the same form