[ ZapPrefix ZapCondition ]
ZapPrefix : This is always the letter 'z'. If the ZapPrefix is 'z' then only the current textbox will be deleted if the ZapCondition is true. If the ZapPrefix is 'Z' then any object grouped to the current textbox will also be deleted if the ZapCondition is true.
ZapCondition : This is any valid condition as defined in Conditional Tokens.
An example would be [a1zd=22] which means zap the current textbox if the value of the token [d] is equal to 22. In that example, the ZapPrefix is 'z' and the ZapCondition is 'd=22'.
Note that Zap Tokens are a special case of Conditional Tokens. For example, we could rewrite the zap token :
The LanguageTag and DayValue (if present) are placed to the left of the ZapPrefix. The AnyToken that is part of the condition has no LanguageTag or DayValue; Q++ uses those of the zap token.