One example of eval being used for extremely practical purposes is with SQL.
Many practical programmers regularly generate SQL strings which are then
passed to a remote server, which are then evaluated. Indeed, all the same sorts
of arguments against eval may be made against SQL:
1. SQL is confusing: it is executed in a completely separate environment, it
breaks lexical scope, and it has a wildly different everything from the Ruby I
am used to, so why should we use it?
2. SQL is vulnerable to injection attacks. The programmer must be responsible
for understanding this and know how to identify and address these faults. But
why should we use it given these risks?
3. Even if 1 above wasn't true in many ways, it still introduces a layer of
indirection. Do we really need that?
Yet, SQL seems to enjoy some success.
I might say: eval is a powerful tool that requires some thoughtful
consideration, and should be used judiciously.
Sent from my iPhone
On Aug 5, 2015, at 7:11 AM, Michael Titke michael.tied...@o2online.de wrote:
On 04/08/2015 16:34, Alexis King wrote:
And that, I think, is the problem: eval seems a lot like a “one size fits
all” approach to problem solving.
...
We write in high-level languages for a reason. There’s no reason to stunt
their ability to abstract by directly calling eval.
I do understand that attitude of staying on top of a platform and in the
high levels of a high level language. Exactly for those reasons some have
written that pityful subroutine called eval and others even maintain it
from time to time - just to not get your feets wet ;-) if not for a very good
reason.
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