Raising a warning or halting when a placeholder is not matched;
Avoid to fail to expand a whole set of placeholders when just one fails to expand - see ticket #79 and how because of a typo in %(run)s all the other placeholders are not expanded ("%(home)s/AIMES-SC2014-experiments/bag-%(my_bag-size)s_run-%(run)s_task-%(cardinal)s").
For example:
%(run)sall the other placeholders are not expanded ("%(home)s/AIMES-SC2014-experiments/bag-%(my_bag-size)s_run-%(run)s_task-%(cardinal)s").