Dear Ben, Tim and others,
I've been learning a lot from this entire thread. Thanks to all the
responders.
Tim writes:
[...] [W]e can indeed add another item to Kripa's list:
* context confusion
eval() executes in the context in which it's called, not the
context in which the
KS == Kripa Sundar [EMAIL PROTECTED] writes:
KS Dear Ben, Tim and others,
KS I've been learning a lot from this entire thread. Thanks to all the
KS responders.
i just want to reiterate my view on string eval (and symrefs). they are
powerful tools that are needed to solve a certain class
i just want to reiterate my view on string eval (and symrefs). they are
powerful tools that are needed to solve a certain class of
problems. they rarely are the best solution [...]
so my rule again (and kripa, tell your cow-orker this one) is:
you should not use string eval (or symrefs)
Ben Tilly wrote:
I agree that using eval here is wrong. But I still
don't see action at a distance.
You can argue about whether it is action at a distance, but you
have tight coupling between the internals of make_generator
and the string passed into it that was generated from very far
On 8/16/05, Tim King [EMAIL PROTECTED] wrote:
Ben Tilly wrote:
I agree that using eval here is wrong. But I still
don't see action at a distance.
You can argue about whether it is action at a distance, but you
have tight coupling between the internals of make_generator
and the string
Hi, Ben. I began crafting an on-list reply, only to find I had nothing
substantive to add. Then I began writing a private message, only to
discover that perhaps this still makes interesting discussion. Now I'm
thinking we may be on to something here that actually applies directly
to the
Dear Uri,
Thanks to you and the others for your prompt responses.
another bad point about eval is that it can access and modify lexicals
and globals anywhere in the code. so that can lead to action at a
distance and very hard to find bugs.
I don't quite follow.
Globals are anyway
Dear Tom,
You seem to be blending the concepts of eval and system.
Sorry about the confusing presentation there. My friend had
actually written something like:
--\/BEGIN-\/--
$string = system(\cat $somefile | mail -s \\\$something\\\
On Aug 15, 2005, at 11:17 AM, Kripa Sundar wrote:
I asked him to re-write it as:
system(cat $somefile | mail -s '$something' $audience);
Which of course should really be written as:
system(mail -s '$something' '$audience' $somefile);
___
Which of course should really be written as:
system(mail -s '$something' '$audience' $somefile);
Yes, of course. It is one of the classic useless uses of cat(1).
I had meant to write this also to my friend, but forgot in my
indignation over six backslashes. :-)
peace,
Dear Ben,
another bad point about eval is that it can access and modify lexicals
and globals anywhere in the code. so that can lead to action at a
distance and very hard to find bugs.
[...]
I'm not sure if this is what is referred to, but it applies.
If this is dynamic code where
On 8/15/05, Kripa Sundar [EMAIL PROTECTED] wrote:
Dear Ben,
another bad point about eval is that it can access and modify lexicals
and globals anywhere in the code. so that can lead to action at a
distance and very hard to find bugs.
[...]
I'm not sure if this is what is
From: Kripa Sundar [EMAIL PROTECTED]
Date: Mon, 15 Aug 2005 14:04:48 -0400
Dear Ben,
another bad point about eval is that it can access and modify lexicals
and globals anywhere in the code. so that can lead to action at a
distance and very hard to find bugs.
[...]
Kripa Sundar wrote:
I could think of three problems with eval(), and replied to him with
the three points below. Please let me know if I have gotten anything
wrong below. Also, if you can think of more eval() concerns, please
help me learn. TIA.
I think you've pretty well covered the
From: Kripa Sundar [EMAIL PROTECTED]
Date: Sun, 14 Aug 2005 18:15:08 -0400
Dear fellow mongers,
I saw a friend using an eval() where it was unnecessary. Of course,
eval() is a valuable tool, with many valid uses. But in this specific
instance, it was truly unnecessary, and so
MJD == Mark J Dulcey [EMAIL PROTECTED] writes:
MJD Kripa Sundar wrote:
I could think of three problems with eval(), and replied to him with
the three points below. Please let me know if I have gotten anything
wrong below. Also, if you can think of more eval() concerns, please
Kripa Sundar wrote:
I saw a friend using an eval() where it was unnecessary.
(The code he used was eval $string, where the value of
$string was known at compile-time.)
[...]
* delayed error detection and impact on correctness:
If there is a typo in the system() string that you
TM == Tom Metro [EMAIL PROTECTED] writes:
TM Your comments about doing something that has life beyond the process
TM itself and incomplete run seem a bit muddled and not consistent with
TM how eval behaves. Yes, as another poster pointed out, if you don't check
TM $@ after an eval, an
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