nvi is a version of the vi editor which supports all the historic ex/vi features except for open mode and the lisp edit option (e.g., it has a fully implemented underlying ex mode). It contains a number of additional features, including an experimental GTK frontend in the development version.
Poplog is a high-level programming environment including the languages: Pop-11, ML, Common LISP (including CLOS), and Prolog. Poplog allows the programmer to write mixed-language programs and perform incremental compilation. It includes a fully customisable text editor (VED) with multi-font capabilities, a comprehensive X interface including Athena, Motif, and OLIT widget set support, a custom Poplog widget set including a neat text-editing widget, and an easy to use graphics widget. It supports graphics elements such as graph drawing, turtle graphics, high-level support for creating dialog-box based applications, and a multi-window X based implementation of VED (XVed). Poplog implementations are available for Solaris and Intel Linux, AIX on PPC, Digital Unix Alpha and Windows9X/NT.
PerlComposer (formerly known as VisualPerl) is a GUI builder which can be used to write GTK/GNOME programs in Perl with a WYSIWYG interface builder. Currently, it only contains an interface builder, text editor, and project manager. In the future, it will include a debugger, profiler, and version control system as well. The goal is to produce a fully-functional rapid prototype design (RAD) tool for Perl/GTK.
Poedit is a gettext translation (.po file) editor for Unix, Windows, and OS X. It aims to provide translators with a simple, easy to use user interface with all the essential tools such as spellchecker or translation memory. It can also be used to manage translations for small projects.