Open an arbitrary number of resources safely in ruby

tunah (Sam McCall) — Tue, 22 Apr 2008 00:44:04 GMT

I'm too lazy to work out what happens if I try filenames.map {|f| File.open(f) } and the thirteenth file doesnt exist, but I bet I don't like it.

module Enumerable

  # Example:

  # ['a','b'].with_files {|f,g| ... }

  # is the same as

  # File.open('a') {|f| File.open('b') {|g| ... } }

  # You can specify modes with

  # [['a', 'rb'], ['b', 'w']].with_files ...

  def with_files(

      meth = File.method(:open),

      offset=0,

      inplace=false,

      &block

  )

    if inplace then

      if offset >= length then

        yield self

      else

        fname,mode = *self[offset]

        File.open(fname,mode) {|f| 

          self[offset] = f

          self.with_files(meth,offset+1,true,&block)

        }

      end

    else

      dup.with_files(meth,offset,true,&block)

    end

  end

end

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Open an arbitrary number of resources safely in ruby