Confused about Python's with statement

Question

I saw some code in the Whoosh documentation:

with ix.searcher() as searcher:
    query = QueryParser(\"content\", ix.schema).parse(u\"ship\")
    results = searc         


        

Answer 1

Read http://www.python.org/dev/peps/pep-0343/ it explains what the with statement is and how it looks in try .. finally form.

Answer 2

Example straight from PEP-0343:

with EXPR as VAR:
   BLOCK

#translates to:

mgr = (EXPR)
exit = type(mgr).__exit__  # Not calling it yet
value = type(mgr).__enter__(mgr)
exc = True
try:
    try:
        VAR = value  # Only if "as VAR" is present
        BLOCK
    except:
        # The exceptional case is handled here
        exc = False
        if not exit(mgr, *sys.exc_info()):
            raise
        # The exception is swallowed if exit() returns true
finally:
    # The normal and non-local-goto cases are handled here
    if exc:
        exit(mgr, None, None, None)