# New Ticket Created by Autrijus Tang # Please include the string: [perl #39792] # in the subject line of all future correspondence about this issue. # <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=39792 >
Currently :immediate in PIR serves two purposes: Running loadlib for type lookups, and for initializing PMC constants that cannot be expressed in .const syntax. Note that both are independent of environment. I propose a new pragma, .loadlib, that implements the first need. The .const syntax can be extended to express structured constants, perhaps in a restricted set of semantics that allows only PMC initialization and give it explicit names, instead of the current dubious use of a subroutine name as a constant PMC name. The win here is that 3rd-party tools, as well as humans, can see hich libs a .pir is loading, and which constants it's playing with, _without_ running Parrot instructions that can rm-rf the hard disk. If this proposal is accepted, we can convert existing :immediate uses to use it. We can then leave :immediate alone with clear wording saying "deprecated, use .loadlib and .const -- if you think you have a legitimate use to it, let us know, and we can un-deprecate it", instead of removing it outright. The reason for deprecation is that unlike Perl 5, where BEGIN and INIT are often run in the same process, Parrot has a much better design that makes .pbc platform- independent. In that case, any runtime-environment-dependent code in :immediate will be referring to the _COMPILING_ instance, not the _RUNNING_ instance, and the mistake of writing BEGIN when one should be writing INIT (that is, :immediate instead of :init) is costly. The drawbacks of the current :immediate implementation include: - Nobody has a use of PIR :immediate for any unbounded (i.e. interacting-with-environment) evaluation - As an intermediate language, the languages targeting it should handle BEGIN in that level, not PIR level - It destroys the assumption of the same .pir compiling to the same .pasm - There is no way to "merely assemble" .pir into .pbc without the potential of rm -rf. - It makes writing a transformer/analyzer for full .pir impossible in other languages Thanks, Audrey
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