[Tarantool-discussions] SQL built-in functions position

[Mergen Imeev]

Hi all. I have a question that I would like to discuss.

The question is about SQL built-in functions. At the moment these 
functions are
partially described in _func and partially in src/box/sql/func.c. I 
received two
completely different suggestions from my reviewers on what to do with these
functions:
1) Move definitions completely to _func. Remove definitions from func.c.
2) Move definitions completely to func.c. Remove definitions from _func.

In the first case, users will be able to see the function definitions. 
Also, in
the future, we may allow these functions to be called from Lua (although not
sure if this is necessary). The main idea is 'all functions have the same
interface'.

In the second case, the implementation is simpler, and we can more easily
implement some features, such as "virtual" functions. For users, the 
definition
can only be seen in the documentation. The main idea is 'SQL built-in 
functions
are part of SQL'.

Which of these approaches do you think is more beneficial to us?