Opinions on Eval in Lisp, Python and Ruby - The Results of The Poll.

During September 2009, I made three polls with question "what do you think about eval?" for Lisp, Python and Ruby programmers separately. In total, there were 104 votes, between 30-40 for each language. Here are the results, graph and interpretations:

.                                                  Lisp          %     Python          %       Ruby          %
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Eval is evil, harmful or at least unnecessary         2        4.9          7       21.9          0        0.0
Eval is useful but overused                          11       26.8          6       18.8          9       29.0
Eval has just the right place                        16       39.0         10       31.3         19       61.3
Eval is useful but neglected                          3        7.3          4       12.5          1        3.2
Eval is a single most important feature               5       12.2          0        0.0          0        0.0
I do not care for eval                                4        9.8          5       15.6          2        6.5
--------------------------------------------------------------------------------------------------------------
Total                                                41      100.0         32      100.0         31      100.0

(Those who voted they do not care about eval are ignored on graph.)



Great majority of Ruby programmers are satisfied with eval, and significant minority believe that eval is useful but overused. That means that Ruby designer should slightly discourage use of eval, or Ruby community should discuss the issue to reach understanding why and how not to use eval, or why use of eval is justified. Rubyists are not extremists - no one has extreme opinion, and it suggests that they have good capacity for cooperation - at least from the point of view of this, single aspect - which is not unimportant, since recently Ruby is frequently discussed in connection with metaprogramming.

The difference between Python programmers is more significant; majority of them think that eval has the right place in Python, and nearly equal number think that it is overused or neglected. However, large number of Python programmers believe that "eval is evil." Such a large group with extreme opinion suggests that Python community might separate in future on the group that wants Python to be more static, probably compiled - and others. Or, one group will prevail, and others will leave.

In Lisp community, it is exactly opposite: almost 15% Lisp programmers think that eval is essential, and about 5% think eval is evil. It is somehow strange that more Lispers than Rubyists are extremely against eval. Both extremes are significant, and it guarantees consistent disagreements and discussions on the topic. That means, community cannot be united - and it is not united, of course. Even in this single issue, fragmentation of Lisp community is justified.

Another possibility is that some Lisp programmers are not attracted by technical merits of the language, but by its allure - result of Lisp's long history, romantic AI past, and compliments given by programmers - celebrities like Yukihiro Matsumoto, Eric S. Raymond, Alan Kay, Paul Graham, Richard Stallman, Gregory Chaitin. However, I believe that those who do not like the language itself, especially its syntax, give up very early.

Comments are welcome.

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