Beefy Boxes and Bandwidth Generously Provided by pair Networks
P is for Practical
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??

Considering that nothing comes from nothing, everything that has ever come into being had a "setter" of some type. Read-only doesn't exist, by that definition.

As far as I can see, persistence makes the case for the applicability of a ROIA in the role of unique id. When as stored object is reconstituted, will the object handle be exactly the same value as it was before? Obviously not, handles must be recycled or we would have run out by now. Therefore it could not serve this purpose. We don't need the horsepower or overhead of a method, there is nothing to calculate. The value rightly belongs to the object itself. Why not us an instance variable that can't be changed? Actually, if we are willing to shorten our attention span slightly, the unique id in the reconstituted object is an example of read-only.

What details are missing? I think we all understand the concept of a unique id and how they are used. Enough to know they are fundamental to relational databases, serializations schemes, object handles, etc. Do nothing? I think not.

How do you implement unique ids in objects without using an ROIA?


In reply to Re^4: The fallacy of the *requirement* for read-only instance variables. by GotToBTru
in thread The fallacy of the *requirement* for read-only instance variables. by BrowserUk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • Outside of code tags, you may need to use entities for some characters:
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others chilling in the Monastery: (8)
    As of 2014-09-20 14:11 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      How do you remember the number of days in each month?











      Results (159 votes), past polls