Introduction
The 'view' in Scythe is the current working collection of mail. The messages that make up the view are determined by 'view clauses'.
Clause format
A view clause consists of between one and three arguments. Each argument is an expression and so can be arbitrarily complicated. The first two arguments expect (as in, are only useful with) expressions that return words (either a single value or a list), the last expression is evaluated in a boolean sense.
The three arguments are: folder, sequence and filter. The general form of a clause is folder sequence filter.
Folder
folder holds the folders which should be considered for this clause. If folder is the only argument then all mail in the folders is selected by the clause. The following clause selects all mail in the folders 'inbox' and 'work':
The folder name 'all' selects all folders.
Sequence
sequence holds the sequences which should be considered for this clause. The following clause selects all unseen mail in the folders 'inbox' and 'work':
The sequence name 'all' selects all mail in the folder concerned.
Filter
The filter argument holds a test that mail must pass to form part of the clause. The follow clause selects all unseen mail in the folders 'inbox' and 'work', but only from addresses listed in $whitelist. You may wish to read more about variables and the environment:
History
Scythe maintains a view history. The history works like a browser's forward and back buttons and allows you to navigate through previous clause lists. Every time you add or delete a clause a new entry is made in the history.
Note that if you move back through the history and then make a change, history entries forwards of that point are lost. Also note, that it is the clauses which are recorded in the history not the list of messages, i.e. due to other changes you've made you may not see the same mails when you return.