After your hint that NGINX_MODULES_HTTP is a USE_EXPAND variable (which I hadn't heard of before), I did a little looking and found this, , which I'm sure you also did.

In /usr/portage/profiles/base/make.defaults, NGINX_MODULES_HTTP (and _MAIL) are already listed as USE_EXPAND variables, and, though I haven't seen any docs on USE_EXPAND, it doesn't seem necessary.

Once I put the appropriate use flags into NGINX_MODULES_HTTP in /etc/make.conf, emerge appears to de-select the other use flags in NGINX_MODULES_HTTP, which is nice, since you can't specify "-useflag" in a USE_EXPAND variable.

In my /etc/make.conf:

NGINX_MODULES_HTTP='fastcgi gzip gzip-static realip stub_status uwsgi'

Then to see what would happen:

# ACCEPT_KEYWORDS='~amd64' emerge -pv nginx

These are the packages that would be merged, in order:

Calculating dependencies… done!
[ebuild N ] app-vim/nginx-syntax-0.3.1 6 kB
[ebuild N ] www-servers/nginx-0.8.38 USE="aio http http-cache pcre ssl vim-syntax -debug -ipv6 -libatomic" NGINX_MODULES_HTTP="fastcgi gzip realip stub_status uwsgi -access -addition -auth_basic -autoindex -browser -charset -dav -degradation -empty_gif -flv -geo -geoip -gzip_static -headers_more -image_filter -limit_req -limit_zone -map -memcached -passenger -perl -proxy -push -random_index -referer -rewrite -secure_link -split_clients -ssi -sub -upstream_ip_hash -userid -xslt" NGINX_MODULES_MAIL="-imap -pop3 -smtp" RUBY_TARGETS="ruby18" 725 kB

Total: 2 packages (2 new), Size of downloads: 731 kB

I know I'm a bit behind the discussion, but I found a change that you might consider useful. If you replace the line:

context[self.new_result s] = self.split_seq(context[self.results], int(self.cols))

with

context[self.new_results] = self.split_seq(Variable(self.results).resolve(context), int(self.cols))

then you can take advantage of Django's automatic context variable resolution feature. This will allow you to use the template tag to split lists that are elements of hashes, etc., instead of just top-level lists in the context dictionary.

I ran into a problem with the code as-is when I wanted to split a list that was an element of a hash in the context. That is, the list was created in the view as variable["hashname"]=[], and the entire hash variable was returned through context. When specified in the template this turned into things like {{for element in variable.hashname}} — which worked fine. But when passed to list_to_columns, it failed with a key lookup. Back in Python, context["variable.hashname"] doesn't exist — you have to know that it's a hash and use the bracket syntax. The Django django.template.Variable object can take care of this type of lookup automatically.

Thanks again!