diff --git a/src/applications/search/compiler/PhutilSearchQueryCompiler.php b/src/applications/search/compiler/PhutilSearchQueryCompiler.php
--- a/src/applications/search/compiler/PhutilSearchQueryCompiler.php
+++ b/src/applications/search/compiler/PhutilSearchQueryCompiler.php
@@ -12,6 +12,8 @@
   const OPERATOR_AND = 'and';
   const OPERATOR_SUBSTRING = 'sub';
   const OPERATOR_EXACT = 'exact';
+  const OPERATOR_ABSENT = 'absent';
+  const OPERATOR_PRESENT = 'present';
 
   public function setOperators($operators) {
     $this->operators = $operators;
@@ -300,6 +302,22 @@
         $require_value = $is_quoted;
 
         switch ($operator) {
+          case self::OPERATOR_NOT:
+            if ($enable_functions && ($token['function'] !== null)) {
+              $operator = self::OPERATOR_ABSENT;
+              $value = null;
+            } else {
+              $require_value = true;
+            }
+            break;
+          case self::OPERATOR_SUBSTRING:
+            if ($enable_functions && ($token['function'] !== null)) {
+              $operator = self::OPERATOR_PRESENT;
+              $value = null;
+            } else {
+              $require_value = true;
+            }
+            break;
           default:
             $require_value = true;
             break;
diff --git a/src/applications/search/compiler/__tests__/PhutilSearchQueryCompilerTestCase.php b/src/applications/search/compiler/__tests__/PhutilSearchQueryCompilerTestCase.php
--- a/src/applications/search/compiler/__tests__/PhutilSearchQueryCompilerTestCase.php
+++ b/src/applications/search/compiler/__tests__/PhutilSearchQueryCompilerTestCase.php
@@ -97,6 +97,8 @@
     $op_and = PhutilSearchQueryCompiler::OPERATOR_AND;
     $op_sub = PhutilSearchQueryCompiler::OPERATOR_SUBSTRING;
     $op_exact = PhutilSearchQueryCompiler::OPERATOR_EXACT;
+    $op_present = PhutilSearchQueryCompiler::OPERATOR_PRESENT;
+    $op_absent = PhutilSearchQueryCompiler::OPERATOR_ABSENT;
 
     $mao = "\xE7\x8C\xAB";
 
@@ -142,6 +144,18 @@
       'title:' => false,
       'title:+' => false,
       'title:+""' => false,
+      'title:""' => false,
+
+      'title:~' => array(
+        array('title', $op_present, null),
+      ),
+
+      'title:-' => array(
+        array('title', $op_absent, null),
+      ),
+
+      '~' => false,
+      '-' => false,
     );
 
     $this->assertCompileFunctionQueries($function_tests);