The directory help where Empress is installed contains the help files that can be accessed by the on-line help facility in Empress. These may be supplemented with your own help files. To make a new help file accessible through Empress, place it in the help directory and make an entry for it in the help file dictionary _dict. The file _dict contains entries of the form:
helpfile {, <Tab>} topic
where:
| helpfile | Name of the file displayed when help is requested on the keyword. One file may be associated with several keywords. |
| <Tab> | The tab character is a separator. |
| topic | This may contain asterisks (*) for pattern matching. A * matches any character (including none at all) in the position where it appears. For example, the entry edit *ed* allows help edit, help ed, and help editor to find the file edit. A ? may also be used to match any single character, as in Empress Query Language pattern matching. The keyword should not contain embedded blanks. |
When help topic is typed into Empress, the _dict file is searched linearly until a match for topic is found in the keyword list. Keywords that use no pattern matching, being more specific in terms of matching requirements, should appear earlier in the list than keywords that use pattern matching so that less specific requests will find a help file. For instance, the list:
database database datatype datatype database *data*
is a suitable ordering, but the following list would never allow datatype to be matched:
database database database *data* datatype datatype
As an example, to add a file giving help on error messages you might create a file called errors containing See the Database Administrator. To install this as a help file, move errors into the help directory, and add the following line to _dict:
errors <Tab> *error*
Users will now have the contents of errors printed out when they enter any help request in which the topic contains the word error. To also have the error file printed in response to the command:
help message
add the following line to _dict:
errors <Tab> *message*