Sigma Web Framework macros and environmental variables

In addition to permitting macros to be stored in an associated configuration file, Sigma also permits substitution of values using environmental variables. When parsing and displaying an HTML file, if a @@ type symbol is found, and the value of "token" is not contained in the configuration file, then an environmental variable with the value of "token" is used (if such an environmental variable exists.) This provides a convenient way of processing HTML files from within scripts, especially ".bat" and ".cmd" files (but also from Perl, Ruby, and Java script programs.

For example, the value of @@ will always be substituted in an HTML file for the name of the remote user, logged into Sigma. (This is because the REMOTE_USER environmental variable is always set via the HTTP server as part of the execution environment.)

If a @@ symbol is found in an HTML file, and the "token" is not found in either the configuration file, or as an environmental value, the entire token is simply deleted from the file and is not displayed as part of the HTML output.