Distribute endless Coca-Cola - half is oddly like rum, say (9)

I believe the answer is:

alcoholic

I'm a little stuck... Click here to teach me more about this clue!

'rum say' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.

'distribute endless coca-cola half is oddly' is the wordplay.
'distribute' indicates an anagram (I've seen this in other clues).
'endless' means to look at the middle letters.
'oddly' means one should take alternating letters (letters in the odd-numbered positions are used).
The middle of 'coca' is 'oc'.
'half'+'is'='halfis'
The alternating letters of 'halfis' are 'hli'.
'oc'+'cola'+'hli'='occolahli'
'occolahli' anagrammed gives 'ALCOHOLIC'.

'like' is the link.

Can you help me to learn more?

(Other definitions for alcoholic that I've seen before include "Drunk" , "Dipso" , "Over-tippling" , "I'm addicted" , "One taking Jag frequently" .)

I've seen this clue in The Independent.

Want a hint initially instead of a full solution? Install my app