same pattern as the existing EntryID, i.e. a human readable symbol plus a hash
but the hash is just random, instead of deriving it from the symbol text.
Use case is when we explicitly need a distinct identity, even when the
human readable symbolic name is the same. Actual example: the fork root in the timeline
...it should have been explicit from start, since there is no point
in converting an EntryID into a plain flat string without further notice
this became evident, when the compiler picked the string overload on
MakeRec().genNode(specialID)
...which is in compliance to the rules, since string is a direct match,
while BareEntryID would be an (slicing) upcast. However, obviously we
want the BareEntryID here, and not an implicit string conversion,
thereby discarding the special hash value hidden within the ID
While in general it is fine to clean-up any entity IDs
to be US-ASCII alphanumerics (plus some allowed interpunction),
the GenNodes and also keys in object-bindings for diff are
considerd internal interfaces, assuming that any passed
ID symbol is already sanitised and checked. So the
sanitise operation can be skipped. This changeset
adds the same option directly to lib::EntryID,
allowing to create an EntryID that matches
a similar GenNode's (hash) ID.
- remove unnecessary includes
- expunge all remaining usages of boost::format
- able to leave out the expliti string(elm) in output
- drop various operator<<, since we're now picking up
custom string conversions automatically
- delete diagnostics headers, which are now largely superfluous
- use newer helper functions occasionally
I didn't blindly change any usage of <iostream> though;
sometimes, just using the output streams right away
seems adequate.
...while on the train back from FrOSCon.
still the same old problem: we need a better hash function
for generating our Entry-IDs. The default hash function from Boost performs
poor on strings with common prefix and trailing number.
We use a hackish workaround, which is sufficient to avoid collisions
among the first 10000 numbers.
basically this is the well known problem #587
Just it became more pressing with the Upgrade to Jessie and Boost 1.55
So I've pulled off the well known "Knuth trick" to spread the
input data more evenly within the hash domain.
And voilà: now we're able to use 100000 number suffixes without collision
- move the santitise operation up into EntryID's ctor
- turn the recast() operation into a real in-place cast
these changes should be transparent to the existing usages
of EntryID (within the asset framework), but allow for use
as attribute name holder in GenNode, since we're now able
to feed existing name/ID values directly into the ctor
of BareEntryID, without any spurious santitise operation.
