From: sanjeev mathur <learnsanjeev@...>
Date: 2011-02-16T13:04:04+09:00
Subject: Re: Why use a symbol in place of a variable?

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This is quite good tutorial about symbols and strings here
http://www.robertsosinski.com/2009/01/11/the-difference-between-ruby-symbols-and-strings/

On Wed, Feb 16, 2011 at 6:38 AM, John Feminella <johnf@bitsbuilder.com>wrote:

> A symbol and a variable are two different things. A symbol is
> essentially a special kind of literal, just like a number or a string
> is. You cannot assign values to symbols, just like you can't assign
> values to numbers or strings -- they are their own values. That is, it
> makes no sense to say `42 = "banana"`, just as it makes no sense to
> say `:banana = 42`.
>
> In this case, the author is using the symbol :largecave to represent a
> particular location. The reason why he might prefer a symbol literal
> to a string literal is that symbols are immutable. "Immutable" means
> that you can't do operations on symbols to change them (unlike, say,
> strings). Immutability is a good property because it decreases that
> number of surprises you can have, and because it makes reasoning about
> your program easier.
>
> ~ jf
> --
> John Feminella
> Principal Consultant, BitsBuilder
> LI: http://www.linkedin.com/in/johnxf
> SO: http://stackoverflow.com/users/75170/
>
>
>
> On Tue, Feb 15, 2011 at 19:41, Gaba Luschi <friedoysterlover@gmail.com>
> wrote:
> > Hi,
> > Say you have a method in a class that's defined as this:
> > (working from Peter Cooper's Beginning Ruby book, p. 155 of the book)
> >
> > class Dungeon
> > .
> > .
> > .
> >
> > def start(location)
> > @player.location = location
> > show_current_description
> > end
> >
> > why is it that when you place the player in the large cave, it's
> > my_dungeon.start(:largecave)
> >
> > instead of
> > my_dungeon.start(largecave)
> > ?
> > why is largecave a symbol?
> > Thanks so much!
> >
> > --
> > Posted via http://www.ruby-forum.com/.
> >
> >
>
>

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