Tabbed navigation feature

The "Tabbed Navigation" feature of Sigma, where screens and applications are accessed via a series of nested tabbed folders, is one of the simplest and most powerful aspects of Sigma, and is explained as follows:

When Sigma starts, it looks in the "Sigma\sigma-web" directory, and lists all the objects in this directory that follow a naming convention of "nnn_Name.sfx", where "nnn" is a three digit integer number (with possibly leading zeros), "Name" is the name of the tab, and ".sfx" is the file suffix, defined below.

Any object in the "sigma-web" folder that follows the above naming convention is represented by a (possibly nested) tab, and is accessible to the browser. Any object in the sigma-web directory that does not follow this naming convention is silently skipped.

Supported files suffixes

The action taken on the actual file depends upon the type of suffix. The following (and only the following) suffix values are supported.

• .txt (Text File) Any file with a ".txt" file suffix displayed as preformatted text, bracketed by the "<pre> and "</pre>" tags. The text should be regular ASCII text, and
• .html (HTML file) Any file with a ".html" or ".htm" suffix is displayed as a regular HTML file, interpreted by the browser like any other HTML file on the system
• .exe (System Executable) Any file with a ".exe" suffix is executed, and the standard output of the program is displayed as regular HTML.
• .bat (Batch File) Any file with a ".bat" suffix is executed as a Windows batch file, and the standard output of the program is displayed as preformatted text, bracketed by the "<pre> and </pre> tags.
• .cmd (Link file) Any file with a ".cmd" suffix is executed as a Windows batch file, and the standard output of the program is displayed as regular HTML. (This is similar to the action of a ".bat" file, except the output of the program is not treated as preformatted text.)
• .dir (Directory) Any file with a ".dir" suffix is taken as a directory. The first file in the directory (listed in the numerical order of the "nnn" prefix) is displayed, which can be another directory or any of the file extensions above.

Users can copy text and HTML files into the "sigma-web" directory, or some new subdirectory within that directory. Those files will immediately appear as tabs. The number of tabs at any level is limited to MAX_LIST_ENTRIES (i.e. 1000 items), although in practical terms, it is typical to have only a few tabs, broken down into folders, for easy navigation through the system. (Otherwise, if there are too many tabs, a horizontal scroll bar will open up in the browser display.)

The system is language independent. In particular a ".cmd" file can immediately launch any other scripting language, including PHP, Ruby, Java, or other application that writes to standard output. This opens the door to support for any programming and scripting language.