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Postings from August 2001
One way to implement rewritability could be to allow a ...o once
switch for eval-string. The first time through, the string
is expanded and compiled and run, but subsequent times through
it becomes a simple block.
This feature would greatly simplify source code filters, as
they could be arbitrarily deferred.
The advantages
eval ${code}o;
has over
my $FutureCodeRef;
{
...
&{$FutureCodeRef ||= eval "sub {$code}"}
...
};
are:
Clarity, as it is all in one place instead of requiring
a named variable, which might get overwritten, and additional
context blocks
Faster (no perlop-level conditional, as the eval statement
would get replaced with the new block.
To protect some rewritten code within an eval-as-try block,
we could do this:
eval { eval qq/$code/o }
For ease of parsing, this might work only with explicit qq/.../
just like the switches on qr/.../.
--
David Nicol 816.235.1187
free Dmitry Skylarov
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