10.1 Changes in Oz, Mozart libraries and UI

10.1.1 Loops

* patterns are now supported:

for X#Y in L do ... end

* iterator expressions with a bit of a C-flavor are supported:

for X in Init;Cond;Next do ... end

for example:

for I in 1;I<5;I+1 do ... end

also iterators of the form E1..E2, E1..E2;E3, E1;E3 as before.

* nullary break and continue procedures can be obtained using loop features, e.g:

for break:B X in L do ...{B}... end

* EXPERIMENTAL: loops can be used as expressions using a hidden accumulator, e.g.:

        {Show
         for collect:C
             L in Ls
         do 
            for X in L do 
               if {IsOdd X} then {C X} end 
            end 
         end}

This experimental facility uses loop features collect, append, prepend, minimize, maximize, count, sum, multiply, return, default. For more information check the documentation (``Loop Support'').

10.1.2 ``Failed'' Futures and Module Manager

• {Value.byNeedFail E ?V} binds V to the new notion of a ``failed future''. Any attempt to synchronize on V raises E as an exception.

• The module manager was updated to use ``failed futures'': when a module cannot be successfully linked its value becomes a failed future (instead of a record) which raises the exception which caused linking to fail each time the module is subsequently accessed. Thus, programmers have a chance of catching and recovering from linking errors.

10.1.3 Spaces

• Space.askVerbose returns suspended rather than blocked

• An exception is raised, if the argument to Space.commit refers to a non-existing alternative

• The control condition for application of space operations have been unified and extended, see the documentation

• Space.kill kills a space by injecting fail into it

A full treatment of spaces is available in the Christian Schulte's doctoral dissertation "Programming Constraint Services", from the Mozart publications page.

10.1.4 Distribution Subsystem

• The Oz programmer interface to the distributed subsystem has been extended. Parameters like buffer size and timeouts can now be specified at runtime.

• The family of tools for monitoring the behavior of the Mozart system has been extended with a new member, the Distribution Panel. The tool displays information about known remote Mozart sites, amount of communication, measured round-trip and exported/imported entities. Possibilities to remotely monitor other Mozart processes does also exist.

10.1.5 Constraint Systems

Constraint systems (finite domains, finite sets) have undergone, as usual, various improvements and bug fixes. Check the documentation.

10.1.6 Port Improvements

• Ability to send from a subordinated space to a superordinated space (provided that no local variables and names are referred to).

• SendRecv does a send and returns an answer. For details, see doc. This again works across spaces.

10.1.7 Pickling Format

Unfortunately, old pickles cannot be read by this new system. We do plan to have a generic conversion tool, but face a lack of human resources.

10.1.8 `ozl --rewrite'

The Oz linker (ozl) now supports a new command-line option, `--rewrite', which allows to transform the import URLs used by the output functor. Check the documentation for details.