Several options exist for providing an environment for the development of Ada-language programs. Some useful environments are listed below.
APSE is short for Ada Programming Support Environment. APSE was a U.S. Military specification for developing a programming environment that would support the Ada programming language and Ada-related programming tools.
Emacs is an easily-customized highly-extensible text-editor. Emacs includes a module for Ada-language support as part of the Emacs standard distribution, called 'Ada-mode'. Emacs is available for many Linux distributions as a binary or source package. Emacs is available as a binary installer for Windows, and is also available as an OS agnostic source code package. The Emacs website includes a description of 'Ada-mode' as well as installation and configuration instructions for different operating systems, including a guide to customizing Ada-mode to personal taste. A mailing list and home page specific to Ada-mode is available at the Ada-mode website for answering questions related to Ada development in Emacs.
GPS is an acronym for the GNAT Programming Studio. GPS is a fully-featured integrated development environment. It includes support for multiple platforms and languages, and modern programming tools including a language sensitive editor, graphical debugger, automatic code fixing, and support for version control systems. GPS is supported by AdaCore, and comes with large amount of online documentation, including an online user guide and tutorial. AdaCore also maintains a port of the GUI toolkit GTK called GtkAda, which provides for the development of rich, GUI-based applications with Ada.