uses it heavily, to generate inlined versions of accessors and constructors,
which speeds code up at runtime by a significant amount. String eval is not
without its issues however - it's difficult to control the scope it's used in
-(which determines which variables are in scope inside the eval), and it can be
-quite slow, especially if doing a large number of evals.
+(which determines which variables are in scope inside the eval), and it's easy
+to miss compilation errors, since eval catches them and sticks them in $@
+instead.
-This module attempts to solve both of those problems. It provides an
-C<eval_closure> function, which evals a string in a clean environment, other
-than a fixed list of specified variables. It also caches the result of the
-eval, so that doing repeated evals of the same source, even with a different
-environment, will be much faster (but note that the description is part of the
-string to be evaled, so it must also be the same (or non-existent) if caching
-is to work properly).
+This module attempts to solve these problems. It provides an C<eval_closure>
+function, which evals a string in a clean environment, other than a fixed list
+of specified variables. Compilation errors are rethrown automatically.
=cut
return ($code, $e);
}
-{
- my %compiler_cache;
+sub _make_compiler {
+ my $source = _make_compiler_source(@_);
- sub _make_compiler {
- my $source = _make_compiler_source(@_);
-
- unless (exists $compiler_cache{$source}) {
- $compiler_cache{$source} = _clean_eval($source);
- }
-
- return @{ $compiler_cache{$source} };
- }
+ return @{ _clean_eval($source) };
}
-$Eval::Closure::SANDBOX_ID = 0;
-
sub _clean_eval {
- $Eval::Closure::SANDBOX_ID++;
- return eval <<EVAL;
-package Eval::Closure::Sandbox_$Eval::Closure::SANDBOX_ID;
-local \$@;
-local \$SIG{__DIE__};
-my \$compiler = eval \$_[0];
-my \$e = \$@;
-[ \$compiler, \$e ];
-EVAL
+ local $@;
+ local $SIG{__DIE__};
+ my $compiler = eval $_[0];
+ my $e = $@;
+ [ $compiler, $e ];
}
+$Eval::Closure::SANDBOX_ID = 0;
+
sub _make_compiler_source {
my ($source, @capture_keys) = @_;
+ $Eval::Closure::SANDBOX_ID++;
my $i = 0;
return join "\n", (
+ "package Eval::Closure::Sandbox_$Eval::Closure::SANDBOX_ID;",
'sub {',
(map {
'my ' . $_ . ' = ' . substr($_, 0, 1) . '{$_[' . $i++ . ']};'