> can what Walter is doing be done in other languages, namely Adobe Flex
> AIR/ActionScript?
I don't know Flex's API but I bet you have documentation for that and
can find there whether it has registration of user-defined functions
or not.
> Is "return [expr { $a + $b }]" also written in TCL?
Yes.
> Where does a function registered with the SQLite engine live? Is it
> stored inside the database?
No. It lives in your application and SQLite stores in the connection
only pointer to the function that it should call.
> Do the functions one registers in SQLite with the "function" method have
> at their disposal only simple scalar operators, or can there be loop
> control structures?
Whatever your language supports although I believe you cannot (or have
certain restrictions on) call SQLite API back from inside such
function.
Pavel
On Thu, Nov 19, 2009 at 10:58 AM, Tim Romano <tim.rom...@yahoo.com> wrote:
> Perhaps the list can help me to get beyond some fundamental igorance here.
>
> What is the name for what Walter is doing in the two lines below, and
> can what Walter is doing be done in other languages, namely Adobe Flex
> AIR/ActionScript?
>
> proc sql_addnum { a b } { return [expr { $a + $b }] }
> db function addnum sql_addnum
>
>
> I see "function" documented here http://www.sqlite.org/tclsqlite.html
> and "proc" appears to create a TCL procedure.
>
> Is "return [expr { $a + $b }]" also written in TCL?
>
> Where does a function registered with the SQLite engine live? Is it
> stored inside the database?
> Do the functions one registers in SQLite with the "function" method have
> at their disposal only simple scalar operators, or can there be loop
> control structures?
>
> Thanks
> Tim Romano
>
> Walter Dnes wrote:
>> Whilst trying to get a TCL script to create a function in SQLite I ran
>> into problems and did a lot of Googling. I got very tired of seeing the
>> same old same old...
>>
>> proc sql_sqrt {x} {return [expr {sqrt($x)}]}
>> db function sqrt sql_sqrt
>>
>> It didn't help me because it used only one parameter. It didn't say
>> anything about you
>> - *MUST NOT* have commas between parameters in the function definition
>> - *MUST* have commas between parameters when actually calling it
>>
>> I spent several hours figuring this out. Here's a working example...
>>
>> package require sqlite3
>> sqlite3 db :memory:
>> db eval {create table dual(x varchar(1))}
>> db eval {insert into dual values(' ')}
>> proc sql_addnum { a b } { return [expr { $a + $b }] }
>> db function addnum sql_addnum
>> db eval {select 'Hello world' as x from dual} {puts stdout "$x"}
>> db eval {select 99999999999 as y from dual} {puts stdout "$y"}
>> db eval {select addnum(1, 2) as z from dual} {puts stdout "$z"}
>> db close
>>
>> And the output is...
>>
>> Hello world
>> 99999999999
>> 3
>>
>> Use this code as an example, and it may save someone else some time
>> down the road.
>>
>>
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>>
>
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