Expand part declarations in the builtin library python scripts to avoid having to repeat part decla…

runtime/tools/concat_library.py

 #!/usr/bin/env python
 # Copyright (c) 2012, 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.
 
+from os import path
 import optparse
 import shutil
 import sys
 
 def parse_options(argv):
     parser = optparse.OptionParser(usage="Usage: %prog [options] files")
     parser.add_option("--output",
                       dest="output",
                       help="Write output to FILE.",
                       metavar="FILE")
     (options, arguments) = parser.parse_args(argv[1:])
     if not arguments:
         parser.error("At least one input file must be provided.")
     if not options.output:
         parser.error("No --output provided.")
     return (options, arguments)
 
 
+def concatenate_parts(source, output):
+    with open(source, 'r') as inpt:
+        for line in inpt:
+            # Concatenate all the parts into one big file and
+            # remove all the 'part of' declarations as everything
+            # is in one file.
+            if line.startswith('part '):
+                rest = (line[5:]).strip()
+                if rest.startswith('of'):
+                    output.write('// %s' % line)
+                else:
+                    file_name = rest[1:-2]
+                    dir_name = path.dirname(source)
+                    expanded_file_name = path.join(dir_name, file_name)
+                    concatenate_parts(expanded_file_name, output)
+            else:
+                output.write(line)
+
+
 def main():
     # Print the command that is being run. This is helpful when
     # debugging build errors.
     sys.stderr.write('%s\n' % ' '.join(sys.argv))
     (options, arguments) = parse_options(sys.argv)
     tmp_name = '%s.tmp' % options.output
     with open(tmp_name, 'w') as output:
         for source in arguments:
-            with open(source, 'r') as inpt:
-                for line in inpt:
-                    # Drop unneeded library tags as all the library's files
-                    # are concatenated into one big file here:
-                    # The 'part' and 'part of' library tags are removed.
-                    if line.startswith('#source') or line.startswith('part '):
-                        line = '// %s' % line
-                    output.write(line)
+            concatenate_parts(source, output)
     shutil.move(tmp_name, options.output)
 
 if __name__ == '__main__':
     main()