I have a personal pet peeve about the misuse of terminology when dealing with such names, for which the only solution is to go read the original reference to figure out what they meant by it.
E.g., in this case, to describe a data structure as "purely functional" makes zero sense to me intuitively at first. You need to go read the thesis and realise they're referring to data structures implemented as algebraic data types, which in the context of a purely functional language can themselves be thought of as functions, and can therefore be described as 'functional' ...
But unless you do that, the first thought is going to be "huh? can arrays be further split into imperative vs functional?" "Does he mean immutable?" "Can I use functional arrays in c?" "Are they faster/safer than normal arrays?".
By contrast, I think "Purely Functional Data-Structure Types" would have been a far more intuitive term ... but I suppose the author may have felt that clarifying further wasn't punchy enough, and could have made the thesis more wordy...
E.g., in this case, to describe a data structure as "purely functional" makes zero sense to me intuitively at first. You need to go read the thesis and realise they're referring to data structures implemented as algebraic data types, which in the context of a purely functional language can themselves be thought of as functions, and can therefore be described as 'functional' ...
But unless you do that, the first thought is going to be "huh? can arrays be further split into imperative vs functional?" "Does he mean immutable?" "Can I use functional arrays in c?" "Are they faster/safer than normal arrays?".
By contrast, I think "Purely Functional Data-Structure Types" would have been a far more intuitive term ... but I suppose the author may have felt that clarifying further wasn't punchy enough, and could have made the thesis more wordy...