# recursion in .rhtml views ?
**URL:** \
**Category:** rubyonrails-talk\
**Created:** [April 3, 2007, 11:54am UTC](https://discuss.rubyonrails.org/t/recursion-in-rhtml-views/11202 "2007-04-03T11:54:00Z")\
**Posts on this page:** 2\
**Page:** 1
**Author:**  [@Dmitry\_Yakovkin](https://discuss.rubyonrails.org/u/Dmitry_Yakovkin)\
**Post date:** [April 3, 2007, 11:54am UTC](https://discuss.rubyonrails.org/t/recursion-in-rhtml-views/11202/1 "2007-04-03T11:54:00Z")
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)
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**Author:**  [@Lugovoi\_Nikolai](https://discuss.rubyonrails.org/u/Lugovoi_Nikolai)\
**Post date:** [April 3, 2007, 12:00pm UTC](https://discuss.rubyonrails.org/t/recursion-in-rhtml-views/11202/2 "2007-04-03T12:00:54Z")
use partials?
\_node.erb: \ \<%= node.name %\> \\<%= render :partial =\> 'node', :collection =\> node.children %\>\ \