.. highlightlang:: us

.. index:: eval

.. _eval:

eval
====

.. us.tag  eval NOTREADYENGLISH New400 Programming.Symboltable

:ref:`eval` evaluates the string given as UniScript code.

.. function::  ret = eval(ssString)

.. us.return

**Return Value**

The function does not have a return value. Instead it will create an exception, 
if an error occurs. The exception can be caught with a try/except statement. See
also :ref:`evalp`.

.. us.params

**Parameters**

.. uparam:: ssString

   *ssString* is a string with UniScript code (Statements and or functions).

.. us.example

**Example**

::

   eval("a = 1+1");
   print a;

If :ref:`eval` is used inside a function, all variables used in the eval function
are local variables. If eval needs to access variables from the calling function
they mus be declared as global.
::

   def test(rvData, ssOperator, ssLimit)
   {
      global data, i;

      data = rvData;
      ssString = sprintf("i = find(data %s %s)", ssOperator, ssLimit);
      eval(ssString);
      return i;
   }

   idx = test([1,2,3,4,5,6,7], "<=", "4.5")
   if (idx[1] == 0) {
      MessageBoxError("No data found");
   }
   print idx   // prints 1,2,3,4

.. seealso::
   :ref:`overview-programming`,
   :ref:`evalp`,
   :ref:`eval_file`,
   :ref:`evalp_file`,
   :ref:`load`

:sub:`id-944627`