Once more, a great answer has bit the dust in testing. I wanted to give jacques a different answer than I did to Using STDERR and timestamps to write to a log file, namely,
local *CORE::GLOBAL::die = sub (@) {
die scalar(localtime()), ' ', @_;
};
but
die keeps on dieing the same old way.
$ perl -e'local *CORE::GLOBAL::die = sub (@) {CORE::die(scalar(localti
+me()), " ", @_);}; die "Foo!"'
Foo! at -e line 1.
$
Apparently, die is not overridable. It has a prototype,
$ perl -e'print prototype "CORE::die"'
@$
and it doesn't appear on
diotalevi's toke.c list in
Re: !Overriding Builtin print. Now how do we know which builtins are overridable? Is
die somehow special-cased to not be overridden, as
glob and
readline are to permit it?
Overriding builtins is indeed a tricky business.
Added: Thanks, tye++ and leriksen++. You showed me something I didn't really understand before. It looks like builtins are outside both lexical and dynamic scope, being resolved sometime while compiling. Localizing them has no effect, and the last-compiled override is the one which counts. It's still a little freaky:
BEGIN {
*CORE::GLOBAL::warn = sub (@) {
CORE::warn(scalar(localtime), " ", @_);
};
warn "Foo!";
}
BEGIN {
*CORE::GLOBAL::warn = sub (@) {
CORE::warn( @_);
};
}
warn "Bar!"'
__END__
Foo! at -e line 1.
Bar! at -e line 1.
It looks like BEGIN blocks are all compiled to a single parse tree before they run, but that's only guessing.