'with'文を使ったファイルオープン（かつ自動クローズ）

FileReader.scala

def swith(fileName: String)(f: Iterator[String]=>Unit) {
  val in = new FileInputStream(fileName)
  try {
    f(Source.fromInputStream(in).getLines)
  } finally {
    in.close
  }
}
// 使用例
swith("foo.txt") { lines =>
  for (line <- lines) {
    println( line )
  }
}

read_file_using_with.py

with file('foo.txt') as line:
   for l in line :
     print(l)

read_file_with_closing.py

from contextlib import closing

with closing(file('foo.txt')) as page:
    for line in page:
        print line

# closingはこれと同等
from contextlib import contextmanager
@contextmanager
def closing(file):
    try:
        yield file
    finally:
        thing.close()

Reader.py

class Reader(object):
  def __init__(self, fname):
    self.fname = fname
  def __enter__(self):
    self.file = file(self.fname)
    return self.file
  def __exit__(self, exp_type, exp_value, exp_traceback):
    self.file.close()


# 使用例
with Reader('foo.txt') as lines:
  for line in lines:
    print(line)