Get a compiler error when using "TRUNCATE TABLE tablename;". The same line executes within the standard editor.
Message is "[Error] Syntax check (33:22): Found: "TABLE" Expecting : ; -or- := -or- . -or- @ -or- (ROW."
TRUNCATE is a DDL command and cannot be run directly within pl/sql.
Use
EXECUTE IMMEDIATE 'TRUNCATE TABLE tablename'
or
use DBMS_SQL.EXECUTE (see Oracle documentation for use of this package)