groups is a list of groups, and this function should request data on all those groups. How it does it is of no concern to Gnus, but it should attempt to do this in a speedy fashion.

The return value of this function can be either active or group, which says what the format of the result data is. The former is in the same format as the data from nnchoke-request-list, while the latter is a buffer full of lines in the same format as nnchoke-request-group gives.

group-buffer = *active-line / *group-status

A Gnus group info (see Group Info) is handed to the backend for alterations. This comes in handy if the backend really carries all the information (as is the case with virtual and imap groups). This function should destructively alter the info to suit its needs, and should return the (altered) group info.

There should be no result data from this function.

When the user issues commands for ``sending news'' (F in the summary buffer, for instance), Gnus has to know whether the article the user is following up on is news or mail. This function should return news if article in group is news, mail if it is mail and unknown if the type can't be decided. (The article parameter is necessary in nnvirtual groups which might very well combine mail groups and news groups.) Both group and article may be nil.

There should be no result data from this function.

If the user tries to set a mark that the backend doesn't like, this function may change the mark. Gnus will use whatever this function returns as the mark for article instead of the original mark. If the backend doesn't care, it must return the original mark, and not nil or any other type of garbage.

The only use for this I can see is what nnvirtual does with it---if a component group is auto-expirable, marking an article as read in the virtual group should result in the article being marked as expirable.

There should be no result data from this function.

This function may be called at any time (by Gnus or anything else) to request that the backend check for incoming articles, in one way or another. A mail backend will typically read the spool file or query the POP server when this function is invoked. The group doesn't have to be heeded---if the backend decides that it is too much work just scanning for a single group, it may do a total scan of all groups. It would be nice, however, to keep things local if that's practical.

There should be no result data from this function.

The result data from this function should be a description of group.

description-line = name <TAB> description eol
name             = <string>
description      = <text>

The result data from this function should be the description of all groups available on the server.

description-buffer = *description-line

The result data from this function should be all groups that were created after `date', which is in normal human-readable date format. The data should be in the active buffer format.

This function should create an empty group with name group.

There should be no return data.

This function should run the expiry process on all articles in the articles range (which is currently a simple list of article numbers.) It is left up to the backend to decide how old articles should be before they are removed by this function. If force is non-nil, all articles should be deleted, no matter how new they are.

This function should return a list of articles that it did not/was not able to delete.

There should be no result data returned.

&optional LAST)

This function should move article (which is a number) from group by calling accept-form.

This function should ready the article in question for moving by removing any header lines it has added to the article, and generally should ``tidy up'' the article. Then it should eval accept-form in the buffer where the ``tidy'' article is. This will do the actual copying. If this eval returns a non-nil value, the article should be removed.

If last is nil, that means that there is a high likelihood that there will be more requests issued shortly, so that allows some optimizations.

The function should return a cons where the car is the group name and the cdr is the article number that the article was entered as.

There should be no data returned.

This function takes the current buffer and inserts it into group. If last in nil, that means that there will be more calls to this function in short order.

The function should return a cons where the car is the group name and the cdr is the article number that the article was entered as.

There should be no data returned.

This function should remove article (which is a number) from group and insert buffer there instead.

There should be no data returned.

This function should delete group. If force, it should really delete all the articles in the group, and then delete the group itself. (If there is such a thing as ``the group itself''.)

There should be no data returned.

This function should rename group into new-name. All articles in group should move to new-name.

There should be no data returned.