Why programming puzzlers make me sad

I recently saw a “guess what this does” article on a blog I follow, and this post presents mysterious Perl code for which the reader is asked to guess what it does:

perl -le 'print(two + two == five ? "true" : "false")'

I looked at it briefly, got a headache, and didn’t even want to solve it. This despite using Perl as one of my main programming languages from 1993-2010 and considering myself fairly proficient at Perl.

Programming puzzlers just in general make me sad.

I know every programming language has quirks

It is a human reality, given human imperfection, that the languages we invent have quirks of some kind. You might expect that, unlike natural languages like English and Chinese, which have the burden of no centralized design and hundreds or thousands of year of history and random evolution, computer languages would be designed up front to avoid ambiguity and just plain confusion. But the human desire to make some things “easy” through clever defaults or implicit assumptions always results in an invented computer language that has irregularities or unexpected behavior somewhere.

The strange love of puzzlers

Still, it makes me sad when I see “puzzlers”, and especially how they are used. For some reason, in some circles, it is considered a sign of intelligence or competence to be able to decode strange puzzlers. Many academic homework assignments and exams tend to focus on weird puzzlers as a way of supposedly testing proficiency in programming. Java certification exams and job interview questions often throw in puzzlers. I deplore this situation.

I understand that in specialized circumstances, you would want to value someone who was really good at puzzlers: someone who could write a conforming compiler for a language, diagnose strange bugs, etc. But that is not what most of us do or need to do. And too many puzzlers makes non-programmers wince and stay away from a field they consider to be pointlessly capricious.

When to understand puzzlers

The exception I make is when a “puzzler” is not actually rare code, but typical code that has some kind of mistake. Some languages have more of these puzzlers that are actually critical to understand in order to be functional at working with code in them. For example, almost all normally used features of C could be considered puzzlers!

Languages with “puzzler” books

Many languages have spawned “puzzler” books or sites. You can look them up for yourself if you are curious about puzzlers in your favorite languages. I won’t list any here because I wouldn’t know where to stop. I didn’t mean to pick on Perl, of course, when writing this article.

An idea: how about learning from all the puzzlers?

I have an idea: how about pooling together all the puzzlers in all the languages that currently exist, classifying the language misfeatures that resulted in those puzzlers, and coming up with a plan to

Do you think there would be value in mining existing puzzlers for the purpose of a systematic resource for learning about programming language design?


I don’t like programming puzzlers. They are supposed to be funny, and maybe sometimes they are, but often they are abused for status and mistaken as an accurate gauge of competence.

How do you feel about puzzlers? Do you use them for assessing your own or others’ knowledge? Do you solve them for entertainment? Do you think minimizing the existence of puzzlers should be a criterion for design of any new programming languages?

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