Re: The Concept of References

That looks like an explaination of pointers. It strongly suggests that you can do arithmetic on references, to get to the "next" memory location. I like this image:

           +--------+       
Alias:     | $alias | ------------+
           +--------+             |                          
                                  |
                                 \|/
           +--------+       +----------+       +---------+
Variable:  |  $var  | ----> | Variable | ----> | Content |
           +--------+       +----------+       +---------+
                                 /|\                   
                                  +--------+          
           +--------+       +----------+   |          
Reference: |  $ref  | ----> | Variable | --+          
           +--------+       +----------+
[download]

But that might be too much internals for some.

Comment on Re: The Concept of References Download Code

Replies are listed 'Best First'.
Re^2: The Concept of References by Juerd (Abbot) on Apr 14, 2005 at 12:25 UTC
These things are often called name, container and value. Your diagram has them neatly put in columns: `Name Container Value +--------+ Alias: \| $alias \| ------------+ +--------+ \| \| \\|/ +--------+ +----------+ +---------+ Variable: \| $var \| ----> \| Variable \| ----> \| Content \| +--------+ +----------+ +---------+ /\|\ +--------+ +--------+ +----------+ \| Reference: \| $ref \| ----> \| Variable \| --+ +--------+ +----------+` [download] The "variable" label isn't accurate, though, if you also call one of the blocks "variable". And, to more clearly illustrate that an alias is absolutely not a reference, you could consider making the original name and the second name more visually equal: `+--------+ __ \| $name \| \ +--------+ \ +-----------+ +-------+ ====> \| container \| ----> \| value \| +--------+ / +-----------+ +-------+ \| $alias \| __/ +--------+` [download] And I think the content/value part of Reference is missing in your diagram. It does have one, and that is the actual reference! Hard to draw, though. Juerd # { site => 'juerd.nl', plp_site => 'plp.juerd.nl', do_not_use => 'spamtrap' }	[reply] [d/l] [select]
Re^3: The Concept of References by Anonymous Monk on Apr 14, 2005 at 13:31 UTC
I know how references work internally, but those are details not really needed to understand references and aliases. As for visually equalizing $name and $alias, I usually do the diagram interactively, in front of a blackboard, starting with the middle line of my diagram. And then I won't wipe out the $name box to draw it a bit lower (or higher).	[reply]
Re^2: The Concept of References by leriksen (Curate) on Apr 15, 2005 at 02:27 UTC
Nice diagram - I deliberately didnt do it this way, even though yours is more accurate. And I hope to add The Concept of Alias' today. ...it is better to be approximately right than precisely wrong. - Warren Buffet	[reply]


Perl Monk, Perl Meditation
	PerlMonks