Hi,

I don't understand the problem you're having with aliens. Aliens can be assigned to slots and there is never any reason to call alien-address and <alien> unless you need to do address arithmetic.

Slava

On Sat, Aug 30, 2008 at 1:02 AM, Glenn Tarcea <gtarcea-63aXycvo3TyHXe+LvDLADg@public.gmane.org> wrote:

Hi,

Is there a way to override the >>xxx xxx>> accessors?

The reason I ask is I have code in the BerkeleyDB interface I'm working on that looks as follows:

: <DB-ENV> ( -- DB-ENV/f )

    [let | err [ 0 <int> ] |

       0 err db_env_creat err *int [ \ DB-ENV new swap alien-address >>dbenv ] db-item-create ] ;

The db_env_creat routine is returning a pointer to a DB_ENV. This gets treated as a ALIEN: by factor, and I can't assign that to the >>dbenv write accessor (hence the call to alien-address, which ends up necessitating a later call like 'dbenv>> <alien>' when I need the value in dbenv). What I would like to do is to override >>dbenv to accept a ALIEN: . Or alternatively to have the >>dbenv and dbenv>> automatically do the translation.

Status:

I have basic operations working for BerkeleyDB. I also have interfaces for DB_ENV, DB, Cursors, Sequences, and Transactions. Some of the interfaces are touchy and are going through some refactoring. Currently you can open a DB and a DB_ENV, write to it, and close it. I'm not real happy with my read interface so its going through some changes. The approached I took with the interface was to create a separate set of C routines that hide the DB_ENV->xxx() calls. It also allows me to place the out parameters at the end of the function which allowed me to eliminate a lot of the stack shuffling. I took the C interface code from Elephant which is a persistent object store for Lisp and modified it for my needs.

Thanks,

Glenn

V. Glenn Tarcea

gtarcea-63aXycvo3TyHXe+LvDLADg@public.gmane.org

Hey brother, can you paradigm?

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Another tip: you can write this word without using locals.

: <DV-ENV> ( -- DB-ENV/f )

    0 0 <int> [ db_env_creat ] keep *int [ \ DB-ENV new swap alien-address >>dbenv ] db-item-create ;

Finally, in Factor we throw errors instead of returning null on error, so it is better to have your word check for an error condition and throw an error instead of returning f (assuming that's really what it does).

Slava

On Sat, Aug 30, 2008 at 1:02 AM, Glenn Tarcea <gtarcea-63aXycvo3TyHXe+LvDLADg@public.gmane.org> wrote:

Hi,

Is there a way to override the >>xxx xxx>> accessors?

The reason I ask is I have code in the BerkeleyDB interface I'm working on that looks as follows:

: <DB-ENV> ( -- DB-ENV/f )

    [let | err [ 0 <int> ] |

       0 err db_env_creat err *int [ \ DB-ENV new swap alien-address >>dbenv ] db-item-create ] ;

The db_env_creat routine is returning a pointer to a DB_ENV. This gets treated as a ALIEN: by factor, and I can't assign that to the >>dbenv write accessor (hence the call to alien-address, which ends up necessitating a later call like 'dbenv>> <alien>' when I need the value in dbenv). What I would like to do is to override >>dbenv to accept a ALIEN: . Or alternatively to have the >>dbenv and dbenv>> automatically do the translation.

Status:

I have basic operations working for BerkeleyDB. I also have interfaces for DB_ENV, DB, Cursors, Sequences, and Transactions. Some of the interfaces are touchy and are going through some refactoring. Currently you can open a DB and a DB_ENV, write to it, and close it. I'm not real happy with my read interface so its going through some changes. The approached I took with the interface was to create a separate set of C routines that hide the DB_ENV->xxx() calls. It also allows me to place the out parameters at the end of the function which allowed me to eliminate a lot of the stack shuffling. I took the C interface code from Elephant which is a persistent object store for Lisp and modified it for my needs.

Thanks,

Glenn

V. Glenn Tarcea

gtarcea-63aXycvo3TyHXe+LvDLADg@public.gmane.org

Hey brother, can you paradigm?

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Build the coolest Linux based applications with Moblin SDK & win great prizes
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Factor-talk mailing list

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