Add support for @ and magic constants in search (#974)

The manual-lookup search did not consult is_known_term() or
is_known_variable(), so searching for operators like @ or magic
constants like __LINE__ returned no results. Now these are checked
before falling back to the manual page lookup.

Also adds all magic constants (__LINE__, __FILE__, __DIR__, etc.)
to both $uri_aliases and is_known_term().

Author: lacatoire

error.php

@@ -457,6 +457,16 @@
     "language.oop5.reflection" => "book.reflection", // BC
     "::" => "language.oop5.paamayim-nekudotayim",
 
+    "__line__" => "language.constants.magic",
+    "__file__" => "language.constants.magic",
+    "__dir__" => "language.constants.magic",
+    "__function__" => "language.constants.magic",
+    "__class__" => "language.constants.magic",
+    "__trait__" => "language.constants.magic",
+    "__method__" => "language.constants.magic",
+    "__property__" => "language.constants.magic",
+    "__namespace__" => "language.constants.magic",
+
     "__construct" => "language.oop5.decon",
     "__destruct" => "language.oop5.decon",
     "__call" => "language.oop5.overloading",

include/errors.inc

@@ -472,6 +472,16 @@ function is_known_term(string $term): ?string {
         'yield from' => 'language.generators.syntax.php#control-structures.yield.from',
         'yield' => 'language.generators.syntax.php#control-structures.yield',
 
+        '__line__' => 'language.constants.magic.php',
+        '__file__' => 'language.constants.magic.php',
+        '__dir__' => 'language.constants.magic.php',
+        '__function__' => 'language.constants.magic.php',
+        '__class__' => 'language.constants.magic.php',
+        '__trait__' => 'language.constants.magic.php',
+        '__method__' => 'language.constants.magic.php',
+        '__property__' => 'language.constants.magic.php',
+        '__namespace__' => 'language.constants.magic.php',
+
         '__COMPILER_HALT_OFFSET__' => 'function.halt-compiler.php',
         'DEFAULT_INCLUDE_PATH' => 'reserved.constants.php',
         'E_ALL' => 'errorfunc.constants.php',

manual-lookup.php

@@ -27,6 +27,14 @@
 if ($function) {
     $function = strtolower($function);
 
+    // Check known terms and variables (operators like @, magic constants, etc.)
+    if ($path = is_known_variable(str_replace('_', '-', $function))) {
+        mirror_redirect("/manual/$LANG/$path");
+    }
+    if ($path = is_known_term($function)) {
+        mirror_redirect("/manual/$LANG/$path");
+    }
+
     // Try to find appropriate manual page
     if ($file = find_manual_page($LANG, $function)) {
         mirror_redirect($file);