grammaticality - Is it ungrammatical to start a description of the functionality of a mechanism with a bare infinitive?

In technical documentation (I am mainly referring to the documentation for the source code of a computer program), this pattern seems quite common:

function MakeNFrobbers(int n):    

    Construct a list of 10 Frobbers.

However, someone recently claimed that this was not proper English and changed "Construct a list..." to "Creates a list...". The reasoning they gave was as follows:

• "This guy construct" -> no predicate


• "This guy creates" -> better

With "this guy" being unwritten in the typical clipped style of technical documentation.

To be clear, I'm not suggesting that the former is correct while the latter is not; both sound correct to my ear. However, I can't explain why using "construct" is grammatically correct in this context. The only counterpoint I could offer was:

• "This guy allows you to construct" -> also correct

Is the former version using the bare infinitive ungrammatical and the second option the correct way, or are both correct? If both are correct, what is the rule that covers this particular case in regards to using a bare infinitive?

Answer

I'd take the bare infinitive form as short for:

  What function MakeNFrobbers(int n) does is construct a list of 10 Frobbers.

This is a pseudo-cleft sentence, and it does take a bare infinitive after the "is".