It is not possible to read an attribute from a text file, and to evaluate in the AttributCreator.
Example:
Attribut A with Value "Some text @Value(fme_feature_tpye) some more text".
If the text in the editor of the AttributCreator entered, it works of course. But I read the text from a text file (AttributeFileReader).
@Evaluate(@Value(A)) delivers the desired result as error message as attribut like
Failed to evaluate numeric expression 'Some text my_feature_type some more text'. Result is set to null.
It would be useful if a function @Result directly returns the result.