.. _section-Arithmetic:

Arithmetic
----------

Flora has built-in infix functions for the usual arithmetic operations. The \\is operator is used to calculate the value of an arithmetic expression and assign it to a variable. For example:

.. code-block:: flora

    ?x \is (3 + ?y)

Note that all the variables in the expression (?y in this case) have to be *ground* (i.e., have a value) by the time the \\is expression is evaluated. Otherwise, Flora will signal an error.

For a more flexible approach to mathematical expressions, see :ref:`section-CLP(R) math`.