doc: add material on stemming and wildcards

[notmuch] / doc / man7 / notmuch-search-terms.rst

diff --git a/doc/man7/notmuch-search-terms.rst b/doc/man7/notmuch-search-terms.rst
index 315e8494f03d9e18b208cde720eca037a5785c7d..7fb4a27da5cebc15c79157eaea3044f81cfab6c7 100644 (file)
--- a/doc/man7/notmuch-search-terms.rst
+++ b/doc/man7/notmuch-search-terms.rst
@@ -135,6 +135,85 @@ operators, but will have to be protected from interpretation by the
 shell, (such as by putting quotation marks around any parenthesized
 expression).
 
+Stemming
+--------
+
+**Stemming** in notmuch means that these searches
+
+::
+
+        notmuch search detailed
+        notmuch search details
+        notmuch search detail
+
+will all return identical results, because Xapian first "reduces" the
+term to the common stem (here 'detail') and then performs the search.
+
+There are two ways to turn this off: a search for a capitalized word
+will be performed unstemmed, so that one can search for "John" and not
+get results for "Johnson"; phrase searches are also unstemmed (see
+below for details).  Stemming is currently only supported for
+English. Searches for words in other languages will be performed unstemmed.
+
+Wildcards
+---------
+
+It is possible to use a trailing '\*' as a wildcard. A search for
+'wildc\*' will match 'wildcard', 'wildcat', etc.
+
+
+Boolean and Probabilistic Prefixes
+----------------------------------
+
+Xapian (and hence notmuch) prefixes are either **boolean**, supporting
+exact matches like "tag:inbox"  or **probabilistic**, supporting a most flexible **term** based searching. The prefixes currently supported by notmuch are as follows.
+
++------------------+-----------------------+
+|Boolean           |Probabilistic          |
++------------------+-----------------------+
+| **tag:** **id:** | **from:** **to:**     |
+|**thread:**       |**subject:**           |
+|**folder:**       |**attachment**         |
+|**path:**         |                       |
+|                  |                       |
++------------------+-----------------------+
+
+Terms and phrases
+-----------------
+
+In general Xapian distinguishes between lists of terms and
+**phrases**. Phrases are indicated by double quotes (but beware you
+probably need to protect those from your shell) and insist that those
+unstemmed words occur in that order. One useful, but initially
+surprising feature is that the following are equivalant ways to write
+the same phrase.
+
+- "a list of words"
+- a-list-of-words
+- a/list/of/words
+- a.list.of.words
+
+Both parenthesised lists of terms and quoted phrases are ok with
+probabilisitic prefixes such as **to:**, **from:**, and **subject:**. In particular
+
+::
+
+   subject:(pizza free)
+
+is equivalent to
+
+::
+
+   subject:pizza and subject:free
+
+Both of these will match a subject "Free Delicious Pizza" while
+
+::
+
+   subject:"pizza free"
+
+will not.
+
 DATE AND TIME SEARCH
 ====================