What's the difference between to_string () and as_a (string) in specman?

as_a()

allows you to convert an expression to a specific type, not just a string.

These are some examples from the docs

list_of_int.as_a(string)
list_of_byte.as_a(string)
string.as_a(list of int)
string.as_a(list of byte)
bool = string.as_a(bool) (Only TRUE and FALSE can be converted to Boolean; all other strings return an error)
string = bool.as_a(string)
enum = string.as_a(enum)
string = enum.as_a(string) 

      

        
        
        
      

    

UPDATE:

using as_a(string)

and to_string()

does not always give the same results.

var s: string;
s = "hello";
var lint: list of int;
lint = s.as_a(list of int);
print lint;
print lint.as_a(string);
print lint.to_string();

      

        
        
        
      

    

This will print something like this:

lint =
  104
  101
  108
  108
  111
lint.as_a(string) = "hello"
list.to_string() = "104 101 108 108 111"

      

        
        
        
      

    

This is because it to_string

will do for each element of the list and then the list will be concatenated with spaces as_a

, however, converts integers to characters and concatenate them, giving you the word hello

.