podmaster points out that the last example will choke under strict. However on my machine replacing it with Zaxos suggestion

print "Str Eval ret   :",readonly((eval'capture(5)')->[0]);
[download]

use strict;
sub capture {\@_};
sub readonly{ my $v=$_[0]; eval{$_[0]=$v;1} ? 0 : 1 }

$\="\n";
print "No eval        :",readonly(capture(5)->[0]);
eval '
print "In str eval    :",readonly(capture(5)->[0]);
';
eval {
print "In block eval  :",readonly(capture(5)->[0]);
};
print "Block Eval ret :",readonly(eval{capture(5)}->[0]);
print "Str Eval ret   :",readonly((eval'capture(5)')->[0]);
__END__
No eval        :1
In str eval    :1
In block eval  :1
Block Eval ret :1
Str Eval ret   :0

[download]

Yves / DeMerphq
---
Writing a good benchmark isnt as easy as it might look.

Here is an extra test case - this one also returns correctly:

print "Eval all:",eval'readonly(capture(5)->[0])';
[download]

---

You have moved into a dark place.
It is pitch black. You are likely to be eaten by a grue.

You have a precedence/grouping problem:

print "Eval ret:",readonly((eval'capture(5)')->[0]);
[download]

print "Eval ret:",readonly(eval('capture(5)')->[0]);
[download]

Update: Now that is odd that the grouping doesn't work for you,, mine's on Linux/Perl5.6.1.

Update ² : Sure does look like a platform difference, and where one should not be. I can confirm that demerphq's initial results agree with what mine does with that code. It appears that it's only the parenthesized ones that differ.

Update ³ : One more test case:

print "Eval ret:",readonly(eval('capture(5)'->[0]));
[download]

After Compline,
Zaxo

Which OS and Perl version Zaxo? I still get incorrect results

use strict;
use warnings;
sub capture {\@_};
sub readonly{ my $v=$_[0]; eval{$_[0]=$v;1} ? 0 : 1 }

$\="\n";
print "No eval        :",readonly(capture(5)->[0]);
eval '
print "In str eval    :",readonly(capture(5)->[0]);
';
eval {
print "In block eval  :",readonly(capture(5)->[0]);
};
print "Block Eval ret :",readonly(eval{capture(5)}->[0]);
print "Str Eval ret   :",readonly((eval'capture(5)')->[0]);
print "Str Eval ret2  :",readonly(eval('capture(5)')->[0]);
__END__
No eval        :1
In str eval    :1
In block eval  :1
Block Eval ret :1
Str Eval ret   :0
Str Eval ret2  :0
[download]

Yves / DeMerphq
---
Writing a good benchmark isnt as easy as it might look.

On Win NT and AS perl 5.6.1 you get

--<br>
No eval        :1
In str eval    :1
In block eval  :1
Block Eval ret :1
Str Eval ret   :0
Str Eval ret2  :0
--
[download]

Anthony Staines

Not on Win2k / ActivePerl 5.6.1 they don't. So this could be a platform issue then?

No eval        :1
In str eval    :1
In block eval  :1
Block Eval ret :1
Str Eval ret   :0
Str Eval ret2  :0
[download]

Update:

On the same machine, with cygwin and perl 5.6.1, it runs fine:

No eval        :1
In str eval    :1
In block eval  :1
Block Eval ret :1
Str Eval ret   :1
Str Eval ret2  :1
[download]

---

You have moved into a dark place.
It is pitch black. You are likely to be eaten by a grue.

No eval        :1
In str eval    :1
In block eval  :1
Block Eval ret :1
Str Eval ret   :0
[download]

# added parentheses like so
# print "Str Eval ret  :",readonly(eval('capture(5)')->[0]);

No eval        :1
In str eval    :1
In block eval  :1
Block Eval ret :1
Str Eval ret   :1
[download]

No eval        :1
In str eval    :1
In block eval  :1
Block Eval ret :1
Str Eval ret   :1
Str Eval ret2  :1
[download]

_________
broquaint

Winnt, AS 5.6.1 631.
Using -w i get:

Name "main::capture(5)" used only once: possible typo at strange.pl li
+ne 15.
Use of uninitialized value in eval "string" at strange.pl line 15.

No eval        :1
In str eval    :1
In block eval  :1
Block Eval ret :1
Str Eval ret   :0
[download]

Modification of a read-only value attempted at strange.pl line 4.
[download]

!?!!

Can you tell me what happens when you use the code in Re: Re: Eval str return different from Eval block return?

We are running the same version of Perl so im suprised we are having different results. (ok im W2k not NT propper, but still...)

Thanks,

Yves / DeMerphq
---
Writing a good benchmark isnt as easy as it might look.

Greetings,

The warning disappears then.
I still get

Modification of a read-only value attempted at strange2.pl line 4.
[download]

for $@ at "Block Eval ret" though.
Cheers,
alf

---

You can't have everything: where would you put it?