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**Category:** Rails\
**Created:** [April 3, 2007, 1:55pm UTC](https://www.ruby-forum.com/t/recursion-in-rhtml-views/90972 "2007-04-03T13:55:20Z")\
**Posts on this page:** 2\
**Page:** 1
**Author:**  [@Dmitry\_Y](https://www.ruby-forum.com/u/Dmitry_Y)\
**Post date:** [April 3, 2007, 1:55pm UTC](https://www.ruby-forum.com/t/recursion-in-rhtml-views/90972/1 "2007-04-03T13:55:20Z")
Hi evrybdy,
I have a very simple Albums hierarchy:
class Album \< ActiveRecord::Base
has\_many :books
end
It’s trivial to display a treeview in script/console:
> > def pt(a)
> > pre=’’;a.ancestors.size.times {pre\<\<’ '}
> > p pre+a.name
> > a.children.each { |al| pt al }
> > end
> > =\> nil
>
> > pt Album.find 1
> > “root”
> > " child1"
> > " subchi1"
> > " chi2"
> > " subchi2"
Of course, “p” would not work inside a view, so I google for a while
and find out about “concat”. But concat would not work either with
"undefined \_erbout ".
I was stuck for a while until finally this came to mind:
\<%
def print\_tree(a,out)
pre=’’;a.ancestors.size.times {pre\<\<’ '}
out \<\< pre+a.name+"
"
a.children.each { |al| print\_tree al,out }
end
print\_tree Album.find(1), \_erbout
%\>
So my question is: why is \_erbout out of scope in my inside method?
And what is The Proper Rails way for recursive output? Buffer into a
temp variable? Or something else? And why is it not possible to have
HTML output inside method definition? (like:
\<% def foo (bar)%\>
# \<%=bar.to\_s%\>
\<% end %\>
(disclaimer: of course I know that tail recursion is trivially reduced
to loop. And treeview should probably be AJAX-ed)
---
**Author:**  [@Dmitry\_Y](https://www.ruby-forum.com/u/Dmitry_Y)\
**Post date:** [April 3, 2007, 2:01pm UTC](https://www.ruby-forum.com/t/recursion-in-rhtml-views/90972/2 "2007-04-03T14:01:20Z")
use partials?
\_node.erb:
- \<%= node.name %\>
\<%= render :partial =\> 'node', :collection =\> node.children %\>
2007/4/3, Dmitry Y. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):