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Postings from January 2003
On Wed, 2003-01-29 at 17:50, Spider Boardman wrote: > On 29 Jan 2003 14:29:52 -0500, Aaron Sherman wrote (in part): > > ajs> As for the argument that testing for true non-existentness is a > ajs> burden, check out the way Perl5 does this. Hint: there's a central > ajs> sv_undef, and that's not what array buckets are initialized to.... > > Either you're dead wrong, or you typo'd there. After > > my @a; > $a[4] = 1; > > The array buckets @a[0..3] most certainly ARE initialized to &PL_sv_undef This has changed since I last (long ago) looked at the source for av.c. It once was the case that av_fetch could return NULL for uninitialized cells, which is why it returns an C<SV**> instead of an C<SV*>. It now looks like you're right and newly allocated cells are given a default "undeffing". None the less, the point is valid. We do not HAVE to fill newly allocated arrays with undef. That yeilds a perfectly respectable non-existent case. The question is, do we *want* to do that and is it suitable to the current Parrot implementation? -- Aaron Sherman <ajs@ajs.com> This message (c) 2003 by Aaron Sherman, and granted to the Public Domain in 2023. Fight the DMCA and copyright extension!