I haven't really looked at the semantic aspects of your rewrite yet,
because I'm not exactly sure which advice from Higher Order Perl
you're trying to follow, in particular which coderefs you want to pass
to where...
As it is, it's not clear to me how the three functions are related.
Is snmp_get the toplevel function? If so, how is it supposed to
call the other routines (via coderefs you pass in as args?), etc.
Could you elaborate a bit on how you want the new version to operate,
i.e. what you want to call with which args, and what it should return (a few lines of sample code showing how you're planning to use it would help).
| [reply]
[d/l] |
The advice I am attempting to follow is from page 48 in HOP... "There is an important lesson to learn here: make functions re-entrant by default, because sometimes the usefulness of being able to call a function recursively will be a surprise"...
The behavior I am looking for is to pass in the name of the thing I am looking for, and to generate a hash of the MACs keyed off of the interface names. I am assuming that I need to pass in sub-routines that gather the OIDs from the lookup table, and perhaps call a generic sub that performs the $snmp_sess->get_request.
| [reply] |
because sometimes the usefulness of being able to call a function recursively will be a surprise
It doesn't make any sense to try to follow advice if you don't know what it means.
Your original function does one fairly simple thing. I think it's highly unlikely that
it will ever need to be called recursively. If it turns out that that it will, the
function is already in pretty good shape, because it uses no external variables (that is,
it accesses no global variables and no external lexical variables). However,
it does depend on external state — specifically, the state stored in the
snmp session object; and also whatever is read from the snmp space via the snmp session object.
These factors suggest that making this function re-entrant may be complicated, and it's
quite likely that your little function isn't the right place to solve the problem. On the
other hand, the data from snmp space may be relatively static, and the snmp session may be
a well-behaved black box (storing no state that would impact your function). If this is
the case, then your function is already as recursion-ready as it needs to be.
If you didn't figure out all this yourself, then probably you should simply skip that
nugget of wisdom from HOP, for now.
See also: voodoo programming and You aren't gonna need it.
Between the mind which plans and the hands which build, there must be a mediator... and this mediator must be the heart.
| [reply] |