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Diffstat (limited to 'src/searchterm.h')
| -rw-r--r-- | src/searchterm.h | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/src/searchterm.h b/src/searchterm.h index d596676..646fd77 100644 --- a/src/searchterm.h +++ b/src/searchterm.h @@ -76,6 +76,24 @@ QString tag(const QString &name); /// matches nothing; an empty `addition` leaves `existing` untouched. QString extend(const QString &existing, const QString &addition); +/// Narrows `existing` by everything that is NOT `addition`, as +/// `(existing) AND NOT (addition)`. +/// +/// **Both sides are parenthesised, for the same load-bearing reason as +/// extend().** The query bar may hold a hand-written disjunction, and +/// `a or b AND NOT c` binds as `a or (b AND NOT c)`: the exclusion would cover +/// only the second term, leaving on screen exactly the mail the user asked to +/// be rid of, with no error reported anywhere. +/// +/// **An empty `existing` yields an EMPTY STRING, unlike extend().** Excluding +/// from nothing would mean the entire Maildir minus one value: a legitimate +/// query, and an implausible thing to have meant by right-clicking a value in +/// a fresh window. The menus grey the entry out when the query bar is empty; +/// this is the second layer, against a caller that forgets the guard. +/// +/// An empty `addition` leaves `existing` untouched. +QString exclude(const QString &existing, const QString &addition); + } // namespace SearchTerm /// One entry a context menu can offer: a finished query and the text naming it. |