EVAL  EVAL Evaluate a String


Usage
 
 The eval function evaluates a string.  The general syntax
 for its use is
 
    eval(s)
 
 where s is the string to evaluate.  If s is an expression
 (instead of a set of statements), you can assign the output
 of the eval call to one or more variables, via
 
    x = eval(s)
    [x,y,z] = eval(s)
 
 
 Another form of eval allows you to specify an expression or
 set of statements to execute if an error occurs.  In this 
 form, the syntax for eval is
 
    eval(try_clause,catch_clause),
 
 or with return values,
 
    x = eval(try_clause,catch_clause)
    [x,y,z] = eval(try_clause,catch_clause)
 
 These later forms are useful for specifying defaults.  Note that
 both the try_clause and catch_clause must be expressions,
 as the equivalent code is
 
   try
     [x,y,z] = try_clause
   catch
     [x,y,z] = catch_clause
   end
 
 so that the assignment must make sense in both cases.
 