Idea: klass.from_s(str)

ruby-talk
1

[...]
If you have a klass#to_* method, you should have a
corresponding klass.from_* method if appropriate. This would
make your class more encapsulated, instead of having some of it
in String (or whatever class you are converting from).

Perhaps implement a method_missing in String such as s.to_xxx
will call xxx.from_s ?

cheers

Simon

2

--- "Kroeger Simon (ext)" <simon.kroeger.ext@siemens.com>
wrote:

> [...]
> If you have a klass#to_* method, you should have a
> corresponding klass.from_* method if appropriate. This
would
> make your class more encapsulated, instead of having some
of it
> in String (or whatever class you are converting from).

Perhaps implement a method_missing in String such as s.to_xxx

will call xxx.from_s ?

cheers

Simon

That sounds like a good idea to add a little convienence. That
shows the power of starting with the xxx.from_s(str) method
instead of String#to_xxx where the class is
embedded/abbreviated in the method name.

Here's a demo:

class String
  def method_missing(meth)
    if m = /^to_(.*)$/.match(meth.to_s)
      Class.const_get(m[1].capitalize.to_sym).from_s(self)
    else
      super
    end
  end
end

class Abc
  def self.from_s(s)
    self.new(s)
  end
  def initialize(s)
    @abc = s
  end
  def to_s
    @abc.to_s
  end
end

Abc.from_s("hello") # => #<Abc:0x285c7e0 @abc="hello">
"hello".to_abc # => #<Abc:0x285c7e0 @abc="hello">

···

____________________________________________________
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs

3

Maybe this would be better - making the class an argument
rather than embedding it in the method name:

class String
  def to(klass)
    klass.from_s(self)
  end
end

Abc.from_s("hello") # => #<Abc:0x285c7e0 @abc="hello">
"hello".to(Abc) # => #<Abc:0x285c7e0 @abc="hello">

···

--- Eric Mahurin <eric_mahurin@yahoo.com> wrote:

--- "Kroeger Simon (ext)" <simon.kroeger.ext@siemens.com>
wrote:

>
> > [...]
> > If you have a klass#to_* method, you should have a
> > corresponding klass.from_* method if appropriate. This
> would
> > make your class more encapsulated, instead of having some
> of it
> > in String (or whatever class you are converting from).
>
> Perhaps implement a method_missing in String such as
s.to_xxx
>
> will call xxx.from_s ?
>
> cheers
>
> Simon

That sounds like a good idea to add a little convienence.
That
shows the power of starting with the xxx.from_s(str) method
instead of String#to_xxx where the class is
embedded/abbreviated in the method name.

Here's a demo:

class String
  def method_missing(meth)
    if m = /^to_(.*)$/.match(meth.to_s)
      Class.const_get(m[1].capitalize.to_sym).from_s(self)
    else
      super
    end
  end
end

class Abc
  def self.from_s(s)
    self.new(s)
  end
  def initialize(s)
    @abc = s
  end
  def to_s
    @abc.to_s
  end
end

Abc.from_s("hello") # => #<Abc:0x285c7e0 @abc="hello">
"hello".to_abc # => #<Abc:0x285c7e0 @abc="hello">

__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around