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Postings from November 1999
On Wed, Oct 27, 1999 at 03:14:35PM -0400, Joshua N Pritikin wrote: > > $packed = pack 't', \%data; > > system 'foo', $packed; > > > > $data = unpack 't', shift; > > Ilya, if this is where you are leading then why not advocate including > Storable in the main tarball instead? Simple: AFAIU, Storable is useless for many tasks. Say, it is useless in the above example, since with Storable $packed is almost guarantied to contain an embedded '\0'. The needs of marshalling are very different for different targets, which leads a need to write a marshall/unmarshall code for each of this targets. Now let us look: can this be simplified? The answer is YES: one needs different marshalling code, but this does not mean that one needs different unmarshalling code! How one would write a "universal" unmarshaller? Obviously, one needs to store unmarshalling instructions together with stringified data. This leads to unpack 't' which I wrote. Note that the current version I have comes together with a matched pack 't', but pack-t is very primitive and restricted. As usual, what is important is to have a well-designed *extractor*. Given this, one can write different "compressors" which all will work with the same extractor and will answer different needs. Say, I'm sure one can easily add an option to Storable and FreezeThaw to generate data in the format of such an extractor. And I'm pretty sure that the format supported by unpack 't' is both flexible enough and efficient enough, so that it is good for almost any application. Now: why in the core? One of the reasons is that it deserves it ;-). for other reasons see below. Why not in a module? The closest Perl interface to extraction is unpack(). Reusing existing infrastructure of unpack() allows to write unmarshalling code in 170 additional lines of C. It increases the size of unpack() PP-handler by 1/6th only. Doing it in a separate compilation unit will make things much more complicated and error-prone. And again: (un)marshalling *belongs* to pack()/unpack(). It is exactly the semantic of these operations. And: the stuff added to pp.c is only 4 times the stuff for the support for BER integers. Now compare the usefulness of these features. ;-) Hope this helps, IlyaThread Previous | Thread Next