Hello,
I have two very similar code snippets in two different methods, and I am absolutely sure there is some nice way to DRY them in Ruby... I am still a noob when comes to Ruby idioms so I'd appreciate some help 
...
while element.class != Hpricot::Doc do
path.push element.name
element = element.parent
end
...
and
...
while element.class != Hpricot::Doc do
path.push element
element = element.parent
end
...
i.e. in the first snippet I am pushing element's names, and in the latter the elements themselves.
Thanks,
Peter
http://www.rubyrailways.com
Hello,
I have two very similar code snippets in two different methods, and I am
absolutely sure there is some nice way to DRY them in Ruby... I am still
a noob when comes to Ruby idioms so I'd appreciate some help 
...
while element.class != Hpricot::Doc do
path.push element.name
element = element.parent
end
...
and
...
while element.class != Hpricot::Doc do
path.push element
element = element.parent
end
...
Pull out the loop logic in to another method...
def traverse_up(element)
while element.class != Hpricot::Doc do
yield(element)
element = element.parent
end
end
The two cases now become:
traverse_up(element) {|e| path.push e,name}
and
traverse_up(element) {|e| path.push e}
Additional comments:
It may (or may not) make sense for the traverse_up method to be a member
of element's class.
You might like to provide an additional, optional argument, that can be
used to control loop termination...
def traverse_up(element, terminate_at = Hpricot::Doc)
while !(terminate_at === element) do
yield(element)
element = element.parent
end
end
(I've also changed the way that element's class is checked here - but
classes of Hpricot::Doc will also match and terminate the loop).
Cheers,
Benj
interesting question ...
def element_pusher(root_element, attribute=nil)
while element.class!=Hpricot::Doc do
pushie = attribute.nil? ? element : element.send(attribute.to_sym)
path.push pushie
element = element.parent
end
path
end
good ?
I don't have time to mockup something to test it but
path.push(attribute.nil? ? element : element.send(attribute.to_sym))
might even work ...
jean
jean
···
On 10/4/06, Peter Szinek <peter@rubyrailways.com> wrote:
Hello,
I have two very similar code snippets in two different methods, and I am
absolutely sure there is some nice way to DRY them in Ruby... I am still
a noob when comes to Ruby idioms so I'd appreciate some help
...
while element.class != Hpricot::Doc do
path.push element.name
element = element.parent
end
...
and
...
while element.class != Hpricot::Doc do
path.push element
element = element.parent
end
...
i.e. in the first snippet I am pushing element's names, and in the
latter the elements themselves.
Thanks,
Peter
http://www.rubyrailways.com
Hello,
I have two very similar code snippets in two different methods, and I am
absolutely sure there is some nice way to DRY them in Ruby... I am still
a noob when comes to Ruby idioms so I'd appreciate some help
how about (untested)...
def element_and_each_ancestor(element)
while element.class != Hpricot::Doc do
yield element
element = element.parent
end
end
...
while element.class != Hpricot::Doc do
path.push element.name
element = element.parent
end
...
element_and_each_ancestor(element) do |el|
path.push el.name
end
and
...
while element.class != Hpricot::Doc do
path.push element
element = element.parent
end
...
element_and_each_ancestor(element) do |el|
path.push element
end
i.e. in the first snippet I am pushing element's names, and in the
latter the elements themselves.
ta,
dave
···
On Wed, Oct 04, 2006 at 10:05:41PM +0900, Peter Szinek wrote:
--
http://david.holroyd.me.uk/
Option 1: don't. It's a very small snippet of code.
Option 2:
def dopush
while element.class!= Hpricot::Doc do
path.push(yield(element))
element = element.parent
end
end
The first snippet becomes
dopush {|e| e.name}
The second snippet becomes
dopush {|e| e}
···
On Wed, 04 Oct 2006 22:05:41 +0900, Peter Szinek wrote:
Hello,
I have two very similar code snippets in two different methods, and I am
absolutely sure there is some nice way to DRY them in Ruby... I am still
a noob when comes to Ruby idioms so I'd appreciate some help
...
while element.class != Hpricot::Doc do
path.push element.name
element = element.parent
end
...
and
...
while element.class != Hpricot::Doc do
path.push element
element = element.parent
end
...
i.e. in the first snippet I am pushing element's names, and in the
latter the elements themselves.
--
Ken Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/
I've added a signing subkey to my GPG key. Please update your keyring.
Peter Szinek wrote:
Hello,
I have two very similar code snippets in two different methods, and I am
absolutely sure there is some nice way to DRY them in Ruby... I am still
a noob when comes to Ruby idioms so I'd appreciate some help
...
while element.class != Hpricot::Doc do
path.push element.name
element = element.parent
end
...
and
...
while element.class != Hpricot::Doc do
path.push element
element = element.parent
end
...
i.e. in the first snippet I am pushing element's names, and in the
latter the elements themselves.
Thanks,
Peter
http://www.rubyrailways.com
A couple of obvious (to me, anyhow) questions:
1. You are "pushing" elements and element names. Are you "pulling" or
"popping" them somewhere else?
2. If you just pushed the element name, could you retrieve the element
from its name?
3. Is there some reason you need two loops up the chain? Could you do
while element.class != Hpricot::Doc do
path.push [element.name => element]
element = element.parent
end
or something similar?
Peter Szinek wrote:
Hello,
I have two very similar code snippets in two different methods, and I am
absolutely sure there is some nice way to DRY them in Ruby... I am still
a noob when comes to Ruby idioms so I'd appreciate some help
If you had this:
def ancestors element
...
while element.class != Hpricot::Doc do
path.push element
element = element.parent
end
path
end
...
while element.class != Hpricot::Doc do
path.push element.name
element = element.parent
end
...
would become: ancestors(element).map{|a|a.name}
and
...
while element.class != Hpricot::Doc do
path.push element
element = element.parent
end
...
would become: ancestors(element)
i.e. in the first snippet I am pushing element's names, and in the
latter the elements themselves.
Thanks,
Peter
cheers
Simon
great !! I like yours better, now I wish I hadn't tried 
jean
···
On 10/4/06, benjohn@fysh.org <benjohn@fysh.org> wrote:
> Hello,
>
> I have two very similar code snippets in two different methods, and I am
> absolutely sure there is some nice way to DRY them in Ruby... I am still
> a noob when comes to Ruby idioms so I'd appreciate some help
>
> ...
> while element.class != Hpricot::Doc do
> path.push element.name
> element = element.parent
> end
> ...
>
> and
> ...
> while element.class != Hpricot::Doc do
> path.push element
> element = element.parent
> end
> ...
Pull out the loop logic in to another method...
def traverse_up(element)
while element.class != Hpricot::Doc do
yield(element)
element = element.parent
end
end
The two cases now become:
traverse_up(element) {|e| path.push e,name}
and
traverse_up(element) {|e| path.push e}
Additional comments:
It may (or may not) make sense for the traverse_up method to be a member
of element's class.
You might like to provide an additional, optional argument, that can be
used to control loop termination...
def traverse_up(element, terminate_at = Hpricot::Doc)
while !(terminate_at === element) do
yield(element)
element = element.parent
end
end
(I've also changed the way that element's class is checked here - but
classes of Hpricot::Doc will also match and terminate the loop).
Cheers,
Benj
jean wrote
great !! I like yours better, now I wish I hadn't tried
Well, thanks, but don't let that put you off (or I'll wish I hadn't).
It's quite interestesting to look at the different approaches. The four
suggestions have three different approaches, and two of the approaches
are _very_ similar (utilisation of yield).