Taken from #ruby-lang with a slight cleanup
(I am piglet)
piglet wonders if someone would be so kind to explain what a symbol
is slowly and clearly so his simple pig brain will understand. “A
symbol is the name of an object” just doesn’t grok.
dagbrown: It’s a name without an object attached to it.
rue: Oo, let me try my state again!
rue: It is a name or description that is only meaningful to the
programmer
rue: Like you can say @status = :connected
rue: The :connected does not mean anything to ruby, only you. You have
decided to call this particular status :connected
piglet tries hard not to look confused.
piglet: how does this fit in with .to_sym or .to_i then?
rue: Those are just ways to construct (or deconstruct) a symbol
rue: The implementation is secondary and has no inherent meaning
rue: So long as you understand what symbols are for (:connected), you
are golden. Then you can take a look at implementation details
piglet: ah seems clearer now… still fuzzy though…
rue: Is there a particular usage that is confusing?
piglet: i’ll get back to you, let me meditate some more
piglet: i like playing with things in irb until i understand, but
these symbols are weird
rue: One more! You could just as well write attr_accessor ‘foo’ . You
are just saying the name of the method you want to create.
rue: All these people with their ‘immediate values’ and ‘integer
representations’ are out to confuse people, I think
piglet: someone should let them know they’ve won, so they will stop
rue: Yep. But do you, sort of, see I what I am saying? They are just
names that are meaningful to YOU. Instead of having to say @status =
1, you can say @status = :connected
Pieter: symbols are like integers you pass to a method to select a
state or something. With symbols you can use human-readable objects
instead of integers
rue hopes for a tentative ‘yes’
rue: That would mean we are about 8000 lines of text better than
ruby-talk
piglet: rue I get it
Pieter: wow
rue: Yays
piglet: are symbols more better, or just ‘more meaningful’?
Pieter: you should post the log to ruby-talk and pimp
rue: More meaningful.
rue: As I mentioned, there are some implementation details that may be
interesting in the current ruby.
piglet is satisfied
rue: The thing that is mostly at the root of all this confusion is
that ruby itself creates some symbols. Mostly because it is a
convenient
rue: The second thing --and this is completely useless knowledge–
is that symbols are in fact processed as ‘immediate values’.
piglet: I guess I have to ask what an immediate value is now.
Pieter:
rue: Normal objects are held as references. Say, a = ‘foo’, a does
not actually contain the object, just a reference
rue: Fixnums and Symbols are actually stored ‘in’ the variable
(references are integers too).
rue: But these are just optimizations. There is no functional reason
this is the way it is.
piglet: fixnums and symbols are faster then because they are actually
stored in the variable and not just being pointed to by the variable?
rue: Precisely.
piglet: I didnt know ruby stored anything in its variables besides
pointer type things
rue: Yep --and the important bit is that it does not matter if it does
or not.
piglet: no it wouldnt matter, but its interesting to know
rue: Oh, hell, I will post on ruby-talk. At least they will have
something to talk about tomorrow even if it is bashing our methodology
piglet: rue, would you mind if I do as Pieter says and post this convo
to ruby-lang, I bet someone will get something out of it.
rue: Oh, sure. Just paste the whole thing all the way down here
piglet:
On Mon, Jan 09, 2006 at 06:01:50PM +0900, Alex C. wrote:
Taken from #ruby-lang with a slight cleanup
(I am piglet)
Woah, that was confusing.
“When I use a symbol,” Humpty Dumpty said, in a rather scornful tone,
“it means just what I choose it to mean - neither more nor less.”
“The question is,” said Alice, “whether you can make symbols mean so
many different things.”
“The question is,” said Humpty Dumpty, “which is to be master - that’s
all.”
– With apologies to Lewis Carroll (1832-1898) Through The Looking Glass
1871
rue: That would mean we are about 8000 lines of text better than ruby-talk
You mean someone doesn’t find cleverly disguised flames and small-scale
holy wars over the simplest statements as helpful and an enrichening
readig experience? Gasp! My youthful dreams and illusions shattered. Oh,
that means I’ll have to pledge not to spam the list with my two cents on
topics dead for a week…
David V.
Senior Compulsive Liar, part-time Spammeister
rue: That would mean we are about 8000 lines of text better than ruby-talk
You mean someone doesn’t find cleverly disguised flames and small-scale
holy wars over the simplest statements as helpful and an enrichening
readig experience? Gasp! My youthful dreams and illusions shattered. Oh,
that means I’ll have to pledge not to spam the list with my two cents on
topics dead for a week…
As long as you’re not the one initiating or perpetuating these “flames
and small-scale holy wars” then by all means feel free to resurect
long dead topics.
There is a lot of stuff happening in the list that I dont comment on
because I’m
too newb yet, but if the topic is still active in a few week or months
perhaps I’ll
have something interesting to say, or at the very least a good question
to ask…
