tools/gn: disallow non-canonical integer literals

tools/gn/parser.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/parser.h"
 
 #include "base/logging.h"
 #include "tools/gn/functions.h"
 #include "tools/gn/operators.h"
 #include "tools/gn/token.h"
@@ skipping 31 matching lines @@
     "  identifiers:\n"
     "\n"
     "          else    false   if      true\n"
     "\n"
     "Integer literals\n"
     "\n"
     "  An integer literal represents a decimal integer value.\n"
     "\n"
     "      integer = [ \"-\" ] digit { digit } .\n"
     "\n"
+    "  Leading zeros and negative zero are disallowed.\n"
+    "\n"
     "String literals\n"
     "\n"
     "  A string literal represents a string value consisting of the quoted\n"
     "  characters with possible escape sequences and variable expansions.\n"
     "\n"
     "      string    = `\"` { char | escape | expansion } `\"` .\n"
     "      escape    = `\\` ( \"$\" | `\"` | char ) .\n"
     "      expansion = \"$\" ( identifier | \"{\" identifier \"}\" ) .\n"
     "      char      = /* any character except \"$\", `\"`, or newline */ .\n"
     "\n"
@@ skipping 645 matching lines @@
         break;
       }
     }
 
     // Suffix comments were assigned in reverse, so if there were multiple on
     // the same node, they need to be reversed.
     if ((*i)->comments() && !(*i)->comments()->suffix().empty())
       const_cast<ParseNode*>(*i)->comments_mutable()->ReverseSuffix();
   }
 }