On Fri, Mar 7, 2014 at 12:49 PM, Dominique Devienne <ddevie...@gmail.com> wrote:
> I think what SQLite lacks is a syntax to define custom function like
> it does for virtual tables. Something like:
>
> create function rpad(x, y) using scripty_module as "return
> PRINTF('%-*s',y,x)";
>
Nice suggestion. This probably falls into case when a small new part
needed on sqlite side and large DSL specific features depending on the
side of the registered module. But you still needs some binary module
for your functions to work
How about "macro expression substitution" feature? Something that
could accept any expression compatible with sqlite as the function
body to be just translated into corresponding vdbe instructions.
For example,
Create function complexcase(x,y) as Case when x < 10 then y else y + 10 end
....
Select complexcase(myField1, myField*10) from t;
On sqlite site, the engine can only syntax check for the create
function body, but the referencing it in actual query would require
actual substitution with the corresponding context-sensitive errors.
This definitely will be more constly in kB on sqlite side than module
approach, but would create a more universal solution.
Just quick thoughts, probably there are plenty of obstacles here :)
Max
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