onto the influence list. If we combine the influences from each
successful match, we get the right result.
+> This is implemented, seems to work ok. --[[Joey]]
+
#### High-level Calculation and Storage
Calculating the full influence list for a pagespec requires trying to match
regular list of simple dependencies. So, the data stored ends up looking
just like what is stored today by the explicit dependency hacks. Except,
it's calculated more smartly, and is added automatically.
+
+> I've implemented influence calculation in `add_depends`. As expected,
+> it means rather a lot more work, and makes some things much slower.
+> Optimisation via `pagespec_match_depends` next.. --[[Joey]]
+
+#### Influence types
+
+Note that influences can also have types, same as dependency types.
+For example, "backlink(foo)" has an influence of foo, of type links.
+"created_before(foo)" also is influenced by foo, but it's a presence
+type. Etc.