Eval(text_expression)

Category: Special function

This function evaluates the text_expression argument as an EasyMorph expression.

This function makes it possible to define EasyMorph expressions externally using parameters.

Return value type: Any (The type of the expression output)

The argument itself must not be an expression with a reference to a column.

In an expression, the eval() function is evaluated first (pre-evaluated) and only then the whole expression is evaluated for every row. Pre-evaluation can be recursive until the final expression doesn't contain the eval() function.

  eval('1+1')  //Returns 2
  
  eval('1' & '+1')  //Returns 2
  
  eval('max(1,2)')  //Returns 2
  
  eval('[Count]+1')  //Evaluated as [Count]+1
  
  eval([Count] & '+1')  //Invalid! Column references are not allowed in argument expressions.
  
  eval({Param1})  //Parameter references to expressions in text format are allowed.
  
  eval("1+" & "eval('1+1')")  //Returns 3  (Nesting eval() is allowed.)