Re: IS and AS

From: Shakespeare <whatsin_at_xs4all.nl>
Date: Mon, 12 Jan 2009 19:15:09 +0100
Message-ID: <496b88b2$0$190$e4fe514c_at_news.xs4all.nl>

O_TEXT schreef:

> Shakespeare a écrit :
>> O_TEXT schreef:

>>> I was wondering what is the difference between IS and AS, in general
>>> PL/SQL code.
>>>
>>>
>>> For instance of FUNCTION book_t, how can oracle know if keyword ending
>>> the header is IS or AS;
>>> I mean if header returns SELF and declare result variable before BEGIN,
>>> or if header returns SELF AS RESULT and declare nothing before BEGIN.
>>>
>>>
>>> CREATE OR REPLACE TYPE BODY book_t
>>> AS
>>> CONSTRUCTOR FUNCTION book_t (id IN INTEGER,
>>> title IN VARCHAR2,
>>> isbn IN VARCHAR2,
>>> pages IN INTEGER)
>>> RETURN SELF AS RESULT
>>> IS
>>> BEGIN
>>> SELF.id := id;
>>> SELF.title := title;
>>> SELF.isbn := isbn;
>>> SELF.pages := pages;
>>> IF isbn IS NULL OR SELF.ck_digit_okay
>>> THEN
>>> RETURN;
>>> ELSE
>>> RAISE_APPLICATION_ERROR(-20000, 'ISBN ' || isbn
>>> || ' has bad check digit');
>>> END IF;
>>> END;
>>> ...

>> It's all a matter of parsing....
>>
>> Shakespeare
>>
>> BTW: in many cases, AS and IS are interchangeable.
> 
> Is it possible to know on which rule PLSQL is based for parsing?
> 
> 
> 

You could check out the syntax diagrams in the docs.

Shakespeare Received on Mon Jan 12 2009 - 19:15:09 CET