template engine: convert generator-based iterator to list-based iterator...
template engine: convert generator-based iterator to list-based iterator
If a template iterator is implemented with generator, the iterator is exhau=
sted
after we use it. This leads to undesired behavior in template. This chang=
e
converts a generator-based iterator to list-based iterator when template en=
gine
first detects a generator-based iterator. All future usages of iterator wi=
ll
use list instead.