Packages in Erlang: new documentation

Ulf Wiger (ÄL2/EAB) <>
Thu Sep 4 11:20:56 CEST 2003


From: Richard Carlsson [mailto:]

>It seems that the information about this, and how it works, has not
>reached enough people. I have therefore written a new piece of
>documentation about packages in Erlang, in the hope that it will
>be better understood, and more people will try it out:
>
>    http://www.csd.uu.se/projects/hipe/packages.html
>
>In particular, see the section about migrating code into packages.
>
>All comments appreciated,

I'll briefly report my experiences with packages so far:


I decided to try packages in a hobby project, called CyberAthletics.
It's a project sponsored by the Swedish Athletics Association aiming
at providing wireless services to the audience at Athletics competitions.

The dotted naming convention did offer a relief from the namespace 
problem. Examples from my CyberAthletics (or "cath" for short) application:

cath.server.contest
           .athlete
           .control
           .db
           .event
           .schedule
           .install
           .application
    .client.client
           .gui
           .gs.browser
              .window
              .contest

I actually like the -import() clauses. I think they add useful 
information, and the discipline it requires is beneficial IMHO.
I dislike the .lists notation, and haven't used it.

A slight nuisance is that the path under src/ becomes cath/server/...
and also under src/ (following the OTP convention) is cath.app.src.
This interferes with tab completion, and I also feel that there is
one level too many in the directory structure. 
I'm not thrilled by the idea of tying module names to directory
structure closer than before. I have yet to come up with a better 
scheme, though.

I modified systools_make.erl in order to make it handle dotted module
names while building boot scripts. I noted that embedded code loading 
doesn't work, but for this, one has to modify erl_prim_loader -- doable, 
but I haven't done it. The 'builder' contrib at jungerl also understands 
dotted names.

All in all I find packages to be an improvement, even though some work
remains in order to integrate it fully with OTP.

/Uffe



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