Extension:External Data/Special variables

In addition to the standard "local variables" that External Data's functions populate when they retrieve data, there are a number of "special variables" that get automatically populated after certain calls. These variables' names all start with two underscors. In some cases (the  and   variables), their values do not hold text but rather a full object, so they may only be useful when called from within, but they are still available to any code that calls them.

The following variables will get populated with parsed text, i.e. calls that include the format parameter:
 * - contains the complete XML structure, for the  format
 * - contains the complete JSON structure, for  format
 * - contains the complete text, for the  format
 * ,,  ,   - contain information about the amount of the original text that was parsed, for use with the start line, etc. parameters

Calls to #get_web_data and #get_soap_data will also populate the following variables:
 * - contains the time that the data was fetched on, as a Unix timestamp
 * -, if data could not be fetched, and a stale cache was used;   otherwise
 * - the number of attempts needed to fetch the data

Calls to #get_file_data will populate the following variable:
 * - holds the name of the file, relative to the  setting (populated only if the   parameter is used)