Is a "built-in" considered to be so for all challenges it CAN solve, or only the one it is DESIGNED to solve?

Question

This question has arisen after reading this answer to a question prohibiting a built-in which solves the problem. The poster argues that the built-in is not defined as "repeat a single integer a number of times equal to that integer" so it doesn't count as a built-in. However, it was brought up in the comments that it SHOULD NOT be valid because the single command solves the challenge regardless of how it is defined.

A simpler situation was also suggested in the comments. Suppose a challenge requested Boolean AND be performed without using a built-in AND operation. It was noted that both Minimum and multiplication have identical output to AND when restricted to the same input values (1-bit numbers).

Should built-ins designed for one task, which incidentally perform some other task as well, be considered a built-in for both tasks?

Answer 1

Stop banning built-ins

It has become sort of a meme at this point, where new challenge posters repeat it as blindly as they repeat “this is code-golf; shortest answer (in bytes) wins”. When asked, and then pressed about the matter, the OP in the linked question couldn’t explain why they banned built-ins.

In reality, there is no reason to do so.

• If you’re compensating for how your own challenge is too simple, then this won’t save it (the Do X without Y problem).

• If you’re trying to rob golf languages of their 1-byte answers, in an attempt to be “fair”, they’ll have 2-byte ones — so who cares? Code golf isn’t an inter-language competition anyway.

• Evidently, as this thread exemplifies, people disagree on what constitutes “using a built-in.”

Personally, I haven’t ever seen a challenge on this website where banning built-ins resulted in higher quality answers — it only leads to arbitrarily constrained ones, and arguments over edge cases like this! I think we should heavily discourage “banning built-ins.”

Answer 2

Challenge askers should really be clearer with what they mean when they ban anything.

There really isn't a concrete definition of what a builtin function is. This is just one edge case of what might be considered a builtin, in addition its not clear if more general functions are builtins (e.g. print5of('#') if the challenge was print ##### with no builtins).

Question askers should really be responsible for stating exactly what they mean when they ban builtins just like when they ban comments or libraries. If they don't, just ask them, hopefully they will oblige.

Answer 3

Yes

Any built-in which performs exactly the prohibited action(s) is prohibited, no matter what.

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Feel free to add your arguments for this position to the below list:

• Who cares about intention? x is a built-in function. x accomplishes the task. No built-in function that accomplish the task are allowed. Therefore, x is not allowed.

• A major goal of banning built-ins is to preclude trivial answers. Even a built-in which wasn't documented to do the particular task still trivialize the problem.

• If No became consensus then golfing language authors could just let the description of all their built-ins be this built-in has no purpose to circumvent prohibitions on built-ins.

• [your argument here]

Answer 4

No

Prohibitions on built-ins only apply to built-ins for which the stated purpose is identical to the prohibited task.

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Feel free to add your arguments for this position to the below list:

• Every code golf answer is a collection of built-ins that accomplish the task.

• If there are other (1 byte) answers that do the same thing so that an answer could be any one of them, then at least all but one are not built-ins for the given task, as there aren't multiple built-ins (one would hope) for any given task.

• A major goal of banning built-ins is to preclude trivial answers which show neither creativity nor deep knowledge; a post which states that a command does what it is defined to do is valueless. In contrast, a post which exposes a command that solves the challenge on its own, in a way which is not immediately obvious from the definition implies some level of creativity or higher-level understanding of the language.

• Built-ins are primarily banned in code-golf challenges; if the challenge bans everything which can solve the problem in 1 byte then they're actually just arbitrarily banning 1 byte solutions in a challenge about reducing bytes. Saying "the winner is the lowest number of bytes, but not lower than N" is something I wouldn't welcome in Code Golf.

• [your argument here]