Re: Java--Passing selector arguments to EZGraph

[Marcus G. Daniels]

>>>>> "TW" == Tom Wainwright <address@hidden> writes:

TW> However, after installing the updated swarm.jar file, I get the
TW> following warning when I run my app.  Is this something I should
TW> worry about?  (Obviously, I installed swarm from Paul Johnson's
TW> rpm.)

Actions called by Swarm (with the exception of language-tagged FCall
actions), are issued by the activity library as Objective C calls and
then forwarded.  Objective C has the property that messages are
distinct from classes and that there are no polymorphic forms to
messages.  A message signature is unique and must have the same
argument types and return types across all classes.  This disembodied
message handle is called a Selector, and it encodes these arguments
and return types.  That warning message is telling you that you have
an `update' method with a void return, but Swarm has one with an
Object return.  It's conventional in Objective C to have most messages
return objects because there is a terse way to string together
expressions.

A few days ago I went through most of the interfaces in Swarm and
removed Object returns for many messages.  Now, with certain
exceptions, only `create-time' or `setter' messages return objects.
Normal `using' phase messages return void when that makes sense and
doesn't cause major cross-module or backward compatibility problems.
Thus, Java users should see less of these warnings, and the common
case of `step', `update', etc. being non-argument and void return will
work without conflict.

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