[PATCH 09/31] lib/parse-sexp: support and, not, and or.

[David Bremner <david@tethera.net>]

All operations and (Xapian) fields will eventually have an entry in
the prefixes table. The flags field is just a placeholder for now, but
will eventually distinguish between various kinds of prefixes.
---
 doc/man7/notmuch-sexp-queries.rst | 16 ++++---
 lib/parse-sexp.cc                 | 76 +++++++++++++++++++++++++++++--
 test/T081-sexpr-search.sh         | 31 +++++++++++--
 3 files changed, 109 insertions(+), 14 deletions(-)

diff --git a/doc/man7/notmuch-sexp-queries.rst b/doc/man7/notmuch-sexp-queries.rst
index 32bfcf21..fef6beaf 100644
--- a/doc/man7/notmuch-sexp-queries.rst
+++ b/doc/man7/notmuch-sexp-queries.rst
@@ -51,7 +51,9 @@ subqueries.
     (for most fields) or *or*. See :any:`fields` for more information.
 
 ``(`` *operator* |q1| |q2| ... |qn| ``)``
-    Combine queries |q1| to |qn|. See :any:`operators` for more information.
+    Combine queries |q1| to |qn|. Currently supported operators are
+    ``and``, ``or``, and ``not``. ``(not`` |q1| ... |qn| ``)`` is equivalent
+    to ``(and (not`` |q1| ``) ... (not`` |qn| ``))``.
 
 ``(`` *modifier* |q1| |q2| ... |qn| ``)``
     Combine queries |q1| to |qn|, and reinterpret the result (e.g. as a regular expression).
@@ -62,11 +64,6 @@ subqueries.
 FIELDS
 ``````
 
-.. _operators:
-
-OPERATORS
-`````````
-
 .. _modifiers:
 
 MODIFIERS
@@ -82,6 +79,13 @@ EXAMPLES
     Match all messages containing "added", but also those containing "add", "additional",
     "Additional", "adds", etc... via stemming.
 
+``(and Bob Marley)``
+    Match messages containing words "Bob" and "Marley", or their stems
+    The words need not be adjacent.
+
+``(not Bob Marley)``
+    Match messages containing neither "Bob" nor "Marley", nor their stems,
+
 .. |q1| replace:: :math:`q_1`
 .. |q2| replace:: :math:`q_2`
 .. |qn| replace:: :math:`q_n`
diff --git a/lib/parse-sexp.cc b/lib/parse-sexp.cc
index 1be5e209..97bfecbd 100644
--- a/lib/parse-sexp.cc
+++ b/lib/parse-sexp.cc
@@ -6,12 +6,69 @@
 /* _sexp is used for file scope symbols to avoid clashing with
  * definitions from sexp.h */
 
+typedef enum {
+    SEXP_FLAG_NONE = 0,
+} _sexp_flag_t;
+
+typedef struct  {
+    const char *name;
+    Xapian::Query::op xapian_op;
+    Xapian::Query initial;
+    _sexp_flag_t flags;
+} _sexp_prefix_t;
+
+static _sexp_prefix_t prefixes[] =
+{
+    { "and",            Xapian::Query::OP_AND,          Xapian::Query::MatchAll,
+      SEXP_FLAG_NONE },
+    { "not",            Xapian::Query::OP_AND_NOT,      Xapian::Query::MatchAll,
+      SEXP_FLAG_NONE },
+    { "or",             Xapian::Query::OP_OR,           Xapian::Query::MatchNothing,
+      SEXP_FLAG_NONE },
+    { }
+};
+
+static notmuch_status_t _sexp_to_xapian_query (notmuch_database_t *notmuch,
+					       const _sexp_prefix_t *parent,
+					       const sexp_t *sx,
+					       Xapian::Query &output);
+
+static notmuch_status_t
+_sexp_combine_query (notmuch_database_t *notmuch,
+		     const _sexp_prefix_t *parent,
+		     Xapian::Query::op operation,
+		     Xapian::Query left,
+		     const sexp_t *sx,
+		     Xapian::Query &output)
+{
+    Xapian::Query subquery;
+
+    notmuch_status_t status;
+
+    /* if we run out elements, return accumulator */
+
+    if (! sx) {
+	output = left;
+	return NOTMUCH_STATUS_SUCCESS;
+    }
+
+    status = _sexp_to_xapian_query (notmuch, parent, sx, subquery);
+    if (status)
+	return status;
+
+    return _sexp_combine_query (notmuch,
+				parent,
+				operation,
+				Xapian::Query (operation, left, subquery),
+				sx->next, output);
+}
+
 /* Here we expect the s-expression to be a proper list, with first
  * element defining and operation, or as a special case the empty
  * list */
 
 static notmuch_status_t
-_sexp_to_xapian_query (notmuch_database_t *notmuch, const sexp_t *sx,
+_sexp_to_xapian_query (notmuch_database_t *notmuch, const _sexp_prefix_t *parent, const sexp_t *sx,
 		       Xapian::Query &output)
 {
 
@@ -31,11 +88,20 @@ _sexp_to_xapian_query (notmuch_database_t *notmuch, const sexp_t *sx,
 	return NOTMUCH_STATUS_SUCCESS;
     }
 
-    if (sx->list->ty == SEXP_VALUE)
-	_notmuch_database_log (notmuch, "unknown prefix '%s'\n", sx->list->val);
-    else
+    if (sx->list->ty == SEXP_LIST) {
 	_notmuch_database_log (notmuch, "unexpected list in field/operation position\n",
 			       sx->list->val);
+	return NOTMUCH_STATUS_BAD_QUERY_SYNTAX;
+    }
+
+    for (_sexp_prefix_t *prefix = prefixes; prefix && prefix->name; prefix++) {
+	if (strcmp (prefix->name, sx->list->val) == 0) {
+	    return _sexp_combine_query (notmuch, parent, prefix->xapian_op, prefix->initial,
+					sx->list->next, output);
+	}
+    }
+
+    _notmuch_database_log (notmuch, "unknown prefix '%s'\n", sx->list->val);
 
     return NOTMUCH_STATUS_BAD_QUERY_SYNTAX;
 }
@@ -53,6 +119,6 @@ _notmuch_sexp_string_to_xapian_query (notmuch_database_t *notmuch, const char *q
 	return NOTMUCH_STATUS_BAD_QUERY_SYNTAX;
     }
 
-    return _sexp_to_xapian_query (notmuch, sx, output);
+    return _sexp_to_xapian_query (notmuch, NULL, sx, output);
 }
 #endif
diff --git a/test/T081-sexpr-search.sh b/test/T081-sexpr-search.sh
index 4e3d755c..5e1bb18d 100755
--- a/test/T081-sexpr-search.sh
+++ b/test/T081-sexpr-search.sh
@@ -9,9 +9,34 @@ fi
 
 add_email_corpus
 
-test_begin_subtest "all messages: ()"
-notmuch search '*' > EXPECTED
-notmuch search --query=sexp "()" > OUTPUT
+for query in '()' '(not)' '(and)' '(or ())' '(or (not))' '(or (and))' \
+            '(or (and) (or) (not (and)))'; do
+    test_begin_subtest "all messages: $query"
+    notmuch search '*' > EXPECTED
+    notmuch search --query=sexp "$query" > OUTPUT
+    test_expect_equal_file EXPECTED OUTPUT
+done
+
+for query in '(or)' '(not ())' '(not (not))' '(not (and))' \
+                   '(not (or (and) (or) (not (and))))'; do
+    test_begin_subtest "no messages: $query"
+    notmuch search --query=sexp "$query" > OUTPUT
+    test_expect_equal_file /dev/null OUTPUT
+done
+
+test_begin_subtest "and of exact terms"
+notmuch search --query=sexp '(and "wonderful" "wizard")' | notmuch_search_sanitize > OUTPUT
+cat <<EOF > EXPECTED
+thread:XXX   2009-11-18 [1/3] Carl Worth| Jan Janak; [notmuch] What a great idea! (inbox unread)
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+test_begin_subtest "or of exact terms"
+notmuch search --query=sexp '(or "php" "wizard")' | notmuch_search_sanitize > OUTPUT
+cat <<EOF > EXPECTED
+thread:XXX   2010-12-29 [1/1] François Boulogne; [aur-general] Guidelines: cp, mkdir vs install (inbox unread)
+thread:XXX   2009-11-18 [1/3] Carl Worth| Jan Janak; [notmuch] What a great idea! (inbox unread)
+EOF
 test_expect_equal_file EXPECTED OUTPUT
 
 test_begin_subtest "single term in body"
-- 
2.30.2\r