tree d7eeb6e3b5494ca1f4c37b29f45ec867f541f6da
parent a3f207eec304063e1eb8733f0844c382dd127bcf
author Andrew Pickford <anpickford@googlemail.com> 1529931468 +0200
committer Andrew Pickford <anpickford@googlemail.com> 1530110078 +0200

Move merging logic into one place in ValueList class, improve error reporting

Refactor the complex logic for dealing with merging different types into one
place - the ValueList.render method. This removes the replication of the logic
in the *item.merge_over methods.

As part of the change the errors reported by ValueList.render when
merging is not allowed have been changed from standard python TypeErrors
to a reclass specific TypeMergeError which has more friendly
error reporting giving the parameter name and locations of the error.

To accomodate the error reporting change dicts and lists are subclassed
in parameters.py to allow a uri tag to placed on a newly created dictionary
or list.