In fpc you assign procedudes with @

Code:
SomeFunction := @SomeExistingFunctionInCode;
Also, i doubt that it compiles in Delphi either like that. If you have a global procedure it must be fixed in type definition:
Code:
TSomeFunction = function (Var: Integer): Integer; // remove "of object"
// that can only be used if the function is defined in a class, such as TForm, TObject or any other