Re: `ri Kernel#open` Bug

On 9/21/07, James Edward Gray II <[e-mail]> wrote:
> $ ri -T Kernel#open
> More than one method matched your request. You can refine
> your search by asking for information on one of:
>
>       Kernel#open, Kernel#open_uri_original_open, Kernel#log_open_files,
>       Kernel#open, Kernel#open
>
> As near as I can tell, it's now impossible to reach the Kernel#open
> documentation.

Not quite impossible, if you don't restrict yourself to ri:

shadowfax:~/Documents rick$ ri -T Kernel#open
More than one method matched your request. You can refine
your search by asking for information on one of:

     Kernel#open, Kernel#open_uri_original_open, Kernel#log_open_files,
     Kernel#open, Kernel#open
shadowfax:~/Documents rick$ qri -T Kernel#open
------------------------------------------------------------ Kernel#open
     open(path [, mode [, perm]] )                => io or nil
     open(path [, mode [, perm]] ) {|io| block }  => obj
------------------------------------------------------------------------
     Creates an IO object connected to the given stream, file, or
     subprocess.

     If path does not start with a pipe character (``|''), treat it as
     the name of a file to open using the specified mode (defaulting to
     ``r''). (See the table of valid modes on page 331.) If a file is
     being created, its initial permissions may be set using the
     integer third parameter.

     If a block is specified, it will be invoked with the File object
     as a parameter, and the file will be automatically closed when the
     block terminates. The call returns the value of the block.

     If path starts with a pipe character, a subprocess is created,
     connected to the caller by a pair of pipes. The returned IO object
     may be used to write to the standard input and read from the
     standard output of this subprocess. If the command following the
     ``|'' is a single minus sign, Ruby forks, and this subprocess is
     connected to the parent. In the subprocess, the open call returns
     nil. If the command is not ``-'', the subprocess runs the command.
     If a block is associated with an open("|-") call, that block will
     be run twice---once in the parent and once in the child. The block
     parameter will be an IO object in the parent and nil in the child.
     The parent's IO object will be connected to the child's $stdin and
     $stdout. The subprocess will be terminated at the end of the block.

        open("testfile") do |f|
          print f.gets
        end

     produces:

        This is line one

     Open a subprocess and read its output:

        cmd = open("|date")
        print cmd.gets
        cmd.close

     produces:

        Wed Apr  9 08:56:31 CDT 2003

     Open a subprocess running the same Ruby program:

        f = open("|-", "w+")
        if f == nil
          puts "in Child"
          exit
        else
          puts "Got: #{f.gets}"
        end

     produces:

        Got: in Child

     Open a subprocess using a block to receive the I/O object:

        open("|-") do |f|
          if f == nil
            puts "in Child"
          else
            puts "Got: #{f.gets}"
          end
        end

     produces:

        Got: in Child


     (also known as open_uri_original_open)

+1 for Maurcio


-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/