Demos I3 - Composition and Typing

Reuseware Composition Framework

We show the latest advances of our composition tool: Reuseware. We present use-cases and running examples, in particular related to Xcerpt and ontology languages (N3).

More info can be found at: http://reuseware.org

Screencasts available at: http://reuseware.sourceforge.net/index.php?title=Screencasts

Contact: Jakob Henriksson (Dresden)

A prototype implementation of a descriptive type system for Xcerpt

A descriptive type system for Xcerpt has been proposed in deliverable I3-D4 and other papers. The intended application is (statically) finding (a certain kind of) errors in programs. Here we present a prototype implementation of the type system. The implementation is able to (statically) check correctness of an Xcerpt program with respect to a type specification. A type specification describes a set of possible data bases to which the program is to be applied and an expected set of results. Program correctness means that all its results are in the expected set. Failure of correctness check suggests error in the program. Under certain conditions such failure indeed means that the program is incorrect.

Additionally, the system provides (approximations of) the set of program results and the sets of values of program variables; this information is useful for programmers (and is produced even when the specification of the expected set of results is not given).
The current implementation works for a restricted, but interesting subset of Xcerpt. In particular only non recursive programs are dealt with. 

The prototype is available at http://www.ida.liu.se/~artwi/XcerptT.

Contact: Artur Wilk (Linköping)

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