lib/parse-sexp: support infix subqueries

This is necessary so that programs can take infix syntax queries from
a user and use the sexp query syntax to construct e.g. a refinement of
that query.

doc/man7/notmuch-sexp-queries.rst

@@ -144,6 +144,10 @@ MODIFIERS
 *Modifiers* refer to any prefixes (first elements of compound queries)
 that are neither operators nor fields.
 
+``(infix`` *atom* ``)``
+    Interpret *atom* as an infix notmuch query (see
+    :any:`notmuch-search-terms(7)`). Not supported inside fields.
+
 ``(matching`` |q1| |q2| ... |qn| ``)`` ``(of`` |q1| |q2| ... |qn|  ``)``
     Match all messages have the same values of the current field as
     those matching all of |q1| ... |qn|. Supported in most term [#not-path]_ or
@@ -187,6 +191,9 @@ EXAMPLES
 ``(id 1234@invalid blah@test)``
     Matches Message-Id "1234@invalid" *or* Message-Id "blah@test"
 
+``(and (infix "date:2009-11-18..2009-11-18") (tag unread))``
+    Match messages in the given date range with tag unread.
+
 ``(starts-with prelim)``
     Match any words starting with "prelim".
 

lib/parse-sexp.cc

@@ -57,6 +57,8 @@ static _sexp_prefix_t prefixes[] =
       SEXP_FLAG_FIELD | SEXP_FLAG_BOOLEAN | SEXP_FLAG_WILDCARD | SEXP_FLAG_REGEX | SEXP_FLAG_EXPAND },
     { "id",             Xapian::Query::OP_OR,           Xapian::Query::MatchNothing,
       SEXP_FLAG_FIELD | SEXP_FLAG_BOOLEAN | SEXP_FLAG_WILDCARD | SEXP_FLAG_REGEX },
+    { "infix",          Xapian::Query::OP_INVALID,      Xapian::Query::MatchAll,
+      SEXP_FLAG_SINGLE },
     { "is",             Xapian::Query::OP_AND,          Xapian::Query::MatchAll,
       SEXP_FLAG_FIELD | SEXP_FLAG_BOOLEAN | SEXP_FLAG_WILDCARD | SEXP_FLAG_REGEX | SEXP_FLAG_EXPAND },
     { "matching",       Xapian::Query::OP_AND,          Xapian::Query::MatchAll,
@@ -242,6 +244,34 @@ _sexp_expand_query (notmuch_database_t *notmuch,
     return status;
 }
 
+static notmuch_status_t
+_sexp_parse_infix (notmuch_database_t *notmuch,  const _sexp_prefix_t *parent,
+		   const sexp_t *sx, Xapian::Query &output)
+{
+    if (parent) {
+	_notmuch_database_log (notmuch, "'infix' not supported inside '%s'\n", parent->name);
+	return NOTMUCH_STATUS_BAD_QUERY_SYNTAX;
+    }
+    try {
+	output = notmuch->query_parser->parse_query (sx->val, NOTMUCH_QUERY_PARSER_FLAGS);
+    } catch (const Xapian::QueryParserError &error) {
+	_notmuch_database_log (notmuch, "Syntax error in infix query: %s\n", sx->val);
+	return NOTMUCH_STATUS_BAD_QUERY_SYNTAX;
+    } catch (const Xapian::Error &error) {
+	if (! notmuch->exception_reported) {
+	    _notmuch_database_log (notmuch,
+				   "A Xapian exception occurred parsing query: %s\n",
+				   error.get_msg ().c_str ());
+	    _notmuch_database_log_append (notmuch,
+					  "Query string was: %s\n",
+					  sx->val);
+	    notmuch->exception_reported = true;
+	    return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
+	}
+    }
+    return NOTMUCH_STATUS_SUCCESS;
+}
+
 /* 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 */
@@ -311,6 +341,10 @@ _sexp_to_xapian_query (notmuch_database_t *notmuch, const _sexp_prefix_t *parent
 		return NOTMUCH_STATUS_BAD_QUERY_SYNTAX;
 	    }
 
+	    if (strcmp (prefix->name, "infix") == 0) {
+		return _sexp_parse_infix (notmuch, parent, sx->list->next, output);
+	    }
+
 	    if (prefix->xapian_op == Xapian::Query::OP_WILDCARD)
 		return _sexp_parse_wildcard (notmuch, parent, sx->list->next->val, output);
 

test/T081-sexpr-search.sh

@@ -689,4 +689,47 @@ id:cf0c4d610911171136h1713aa59w9cf9aa31f052ad0a@mail.gmail.com
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
+test_begin_subtest "infix query"
+notmuch search to:searchbyto | notmuch_search_sanitize > EXPECTED
+notmuch search --query=sexp '(infix "to:searchbyto")' |  notmuch_search_sanitize > OUTPUT
+test_expect_equal_file EXPECTED OUTPUT
+
+test_begin_subtest "bad infix query 1"
+notmuch search --query=sexp '(infix "from:/unbalanced")' 2>&1|  notmuch_search_sanitize > OUTPUT
+cat <<EOF > EXPECTED
+notmuch search: Syntax error in query
+Syntax error in infix query: from:/unbalanced
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+test_begin_subtest "bad infix query 2"
+notmuch search --query=sexp '(infix "thread:{unbalanced")' 2>&1|  notmuch_search_sanitize > OUTPUT
+cat <<EOF > EXPECTED
+notmuch search: Syntax error in query
+Syntax error in infix query: thread:{unbalanced
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+test_begin_subtest "bad infix query 3: bad nesting"
+notmuch search --query=sexp '(subject (infix "tag:inbox"))' 2>&1|  notmuch_search_sanitize > OUTPUT
+cat <<EOF > EXPECTED
+notmuch search: Syntax error in query
+'infix' not supported inside 'subject'
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+test_begin_subtest "infix query that matches no messages"
+notmuch search --query=sexp '(and (infix "from:keithp") (infix "to:keithp"))' > OUTPUT
+test_expect_equal_file /dev/null OUTPUT
+
+test_begin_subtest "compound infix query"
+notmuch search date:2009-11-18..2009-11-18 and tag:unread > EXPECTED
+notmuch search --query=sexp  '(infix "date:2009-11-18..2009-11-18 and tag:unread")' > OUTPUT
+test_expect_equal_file EXPECTED OUTPUT
+
+test_begin_subtest "compound infix query 2"
+notmuch search date:2009-11-18..2009-11-18 and tag:unread > EXPECTED
+notmuch search --query=sexp  '(and (infix "date:2009-11-18..2009-11-18") (infix "tag:unread"))' > OUTPUT
+test_expect_equal_file EXPECTED OUTPUT
+
 test_done