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gDelta

gDelta is a tool that aims to provide more immediate feedback on the impact of changes made to DELPH-IN grammars by comparing parser output from two different states of a grammar. It can be thought of as functioning similar to a diff tool, allowing the comparison of two different versions of the same grammar, but rather than comparing the source code of the grammars it compares parser output from both versions run over the same profiles.

gDelta makes use of a feature weighting algorithm for highlighting features in the grammar that have been strongly impacted by a modification to the grammar, as well as a technique for performing clustering over profile items, which is intended to locate related groups of change. These two techniques are used to build an HTML interface which can be viewed offline.

By providing a high-level picture of the impact that modifications to the grammar has had, the hope is that grammar engineers can use gDelta to more readily check if anything unexpected has happened as well as confirm that desired changes have taken effect, earlier rather than later in the grammar development cycle.

Other applications of gDelta that have been suggested are:

• Grammar documentation and the exploration of linguistic phenomena via investigating the impact of systematically switching off types.
• A means of tracking uncaught regressions by comparing successive previous version of a grammar.

gDelta was created by NedLetcher, TimBaldwin and RebeccaDridan.

How to get it

You can get the latest version thusly:

svn checkout http://svn.nedned.net/gdelta

gDelta is intended to work for all DELPH-IN grammars. If your grammar is not working or you are having any difficulties running gDelta please contact NedLetcher.

Installing gDelta

For now, please see the README.txt file for installation notes.