Re: Implementing (elisp-like) buffers in Perl 6: how to do buffer-localisation of arbitrary package variables?

[premchai21]

Could you have an on-buffer-change hook of some sort that accesses a data structure keeping track of which variables were buffer-local to which buffers and swaps their values in and out appropriately?

That is, something like (quite untested):

sub onBufferChange
{
  my ($from, $to) = @_;
  for my $scl (values $from->{locals}) {
    $$$scl[0] = $globalLocals{$$scl[0]}[1];
  }
  for my $scl (values $to->{locals}) {
    exists $globalLocals{$$scl[0]} or
      $globalLocals{$$scl[0]} = [$$scl[0], $$$scl[0]];
    $$$scl[0] = $$scl[1];
  }
}

I have the feeling I've missed the point...

[jonadab]

++

I actually feel pretty stupid for not seeing that. It's quite simple, really: rather than making the current buffer a package variable on the buffer class, I just make it a method (that functions as an lvalue if need be; I'm pretty sure that's possible in Perl6) on the buffer class, and then I can do whatever symbol table changes I need to do. It makes changing buffers very frequently a little more inefficient, but it won't be a big deal unless you have a lot of buffer-local variables, and in that case it's worth it because you're really using the feature. And actually, it's probably not less efficient than making every variable lookup check for buffer-localness.

I'm happy. Perl6 is going to be so cool. Here's looking forward to the next Apocalypse :-)

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