In Gcas, user interacts with backend CAS through a worksheet which contains a sequence of entries . Multiple worksheets can be opened at once in a tabbed-like environment. For every worksheet there is a single backend process associated with it. Worksheets are like documents in a text editor. They can be named, saved in XML format and loaded subsequently, or exported as PDF/HTML documents.

Results of backend computations are nicely rendered if backend supports conversion to LaTeX. Rendering is done with respect to user's choice of font type and size. In some cases, Gcas is able to hack LaTeX output provided by backend in order to display expressions more convetionally.

Gcas offers autocompletion and syntax hightlighting of entered commands. It uses GtkSourceView style schemes installed on the system.

When user enters a command requiring help or a documentation entry, Gcas tries to display output to be nice and more readable, using Pango markup language and subtle syntax coloring. Because in many cases text is cluttered by examples, they're collapsed and can be expanded individually by clicking a hyperlink.

Currently, Gcas supports the following backends:

  * Giac (http://www-fourier.ujf-grenoble.fr/~parisse/giac.html),
  * Maxima (http://maxima.sourceforge.net/),
  * FriCAS (http://fricas.sourceforge.net/),
  * Octave (https://www.gnu.org/software/octave/). It is not a CAS, and also has native GUI, but it was added for convenience.

Gcas will possibly support more backends in the future.

The goal of this project is to provide a nice GTK-based interface to free math software for those that use GNOME desktop.