Drop all Functions for Single Instance of Microsoft SQL Server

PRINT 'delete all user defined functions'
DECLARE @fn varchar(255)
WHILE (
  SELECT Count(*) from dbo.sysobjects f
  WHERE type = 'FN' AND f.name not like 'fn[_]%diagram%'
  ) > 0
BEGIN
  SET @fn = (
    SELECT TOP 1 name  from dbo.sysobjects f
  WHERE type = 'FN' AND f.name not like 'fn[_]%diagram%'
    )
  SET @fn = 'DROP FUNCTION ' + @fn
  PRINT @fn
  EXEC(@fn)
END