Initial CL to create SDK directory (this will be done as a build step).

frog/frog_options.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /** General options used by the compiler. */
 FrogOptions options;
 
 /** Extracts options from command-line arguments. */
 void parseOptions(String homedir, List<String> args, FileSystem files) {
   assert(options == null);
   options = new FrogOptions(homedir, args, files);
 }
 
 // TODO(sigmund): make into a generic option parser...
 class FrogOptions {
   /** Location of corelib and other special dart libraries. */
   String libDir;
 
   /* The top-level dart script to compile. */
   String dartScript;
 
   /** Where to place the generated code. */
   String outfile;
 
+  // TODO(dgrove): fix this. For now, either 'sdk' or 'dev'. 
+  final config = 'dev';
+
   // Options that modify behavior significantly
   bool enableLeg = false;
   bool legOnly = false;
   bool enableAsserts = false;
   bool enableTypeChecks = false;
   bool verifyImplements = false; // TODO(jimhug): Implement
   bool compileAll = false;
   bool dietParse = false;
   bool compileOnly = false;
 
   // Message support
   bool throwOnErrors = false;
   bool throwOnWarnings = false;
   bool throwOnFatal = false;
   bool showInfo = false;
   bool showWarnings = true;
 
   /**
    * Options to be used later for passing to the generated code. These are all
    * the arguments after the first dart script, if any.
    */
   List<String> childArgs;
 
   FrogOptions(String homedir, List<String> args, FileSystem files) {
-    libDir = homedir + '/lib'; // Default value for --libdir.
+    if (config == 'dev') {
+      libDir = joinPaths(homedir, '/lib'); // Default value for --libdir.
+    } else if (config == 'sdk') {
+      libDir = joinPaths(homedir, '/../lib/corelib/frog');
+    } else {
+      world.error('Invalid reader configuration $config', null);
+      throw('Invalid reader config');
+    }
+
     bool ignoreUnrecognizedFlags = false;
     bool passedLibDir = false;
     childArgs = [];
 
     // Start from 2 to skip arguments representing the compiler command
     // (node/python followed by frogsh/frog.py).
     // TODO(jimhug): break on switch cases seems broken?
     loop: for (int i = 2; i < args.length; i++) {
       var arg = args[i];
 
@@ skipping 66 matching lines @@
             passedLibDir = true;
           } else {
             if (!ignoreUnrecognizedFlags) {
               print('unrecognized flag: "$arg"');
             }
           }
       }
     }
 
     // TODO(jimhug): Remove this hack.
-    if (!passedLibDir && !files.fileExists(libDir)) {
+    if (!passedLibDir && 
+        !files.fileExists(joinPaths(libDir, "/corelib.dart"))) {
       // Try locally
       var temp = 'frog/lib';
       if (files.fileExists(temp)) {
         libDir = temp;
       } else {
         libDir = 'lib';
       }
     }
   }
 }