5.6 Prefix Slots

• man-page or info-manual can be used to specify the documentation for the prefix and its suffixes. The command transient-help uses the method transient-show-help (which see) to lookup and use these values.
• history-key If multiple prefix commands should share a single value, then this slot has to be set to the same value for all of them. You probably don’t want that.
• transient-suffix and transient-non-suffix play a part when determining whether the currently active transient prefix command remains active/transient when a suffix or abitrary non-suffix command is invoked. See Transient State.
• incompatible A list of lists. Each sub-list specifies a set of mutually exclusive arguments. Enabling one of these arguments causes the others to be disabled.
• scope For some transients it might be necessary to have a sort of secondary value, called a "scope". See transient-define-prefix.

5.6.1 Internal Prefix Slots

These slots are mostly intended for internal use. They should not be set in calls to transient-define-prefix.

• prototype When a transient prefix command is invoked, then a clone of that object is stored in the global variable transient--prefix and the prototype is stored in the clone’s prototype slot.
• command The command, a symbol. Each transient prefix command consists of a command, which is stored in a symbol’s function slot and an object, which is stored in the transient--prefix property of the same symbol.
• level The level of the prefix commands. The suffix commands whose layer is equal or lower are displayed. See Enabling and Disabling Suffixes.
• value The likely outdated value of the prefix. Instead of accessing this slot directly you should use the function transient-get-value, which is guaranteed to return the up-to-date value.
• history and history-pos are used to keep track of historic values. Unless you implement your own transient-infix-read method you should not have to deal with these slots.