Inconsistency with IO.readlines

[Justin Rudd]

I've noticed a slight inconsistancy with IO.readlines depending on the
line ending. If the line ending is PC (\r\n) or Unix (\n) then it
works fine no matter the platform. But if the line ending is Mac
(\r), IO.readlines returns one line no matter how many lines it is
supposed to be.

Maybe this isn't such a big deal anymore since Mac OS X uses Unix line
endings, but believe it or not I've got files coming in from Mac OS 9
users.

Anyone else seen this? I'm using a build built from the last stable
snapshot under Cygwin.

 

[gene.tani]

Hmm, don't know OS9 file format, but couldn't you set $/
(==$INPUT_RECORD_SEPARATOR) to last character in the file, something
like that?) Don't think there''s anything like Python universal
newlines (open file in mode "U").

 

[James Edward Gray II]

Let me apologize in advance, because I've not bee following this
thread. I have been working with Gavin Sinclair to document
delegate.rb though, and together we've been hard pressed to find a
single good use for SimpleDelegate...

# ========== ext/input_reader.rb ==========
# ext/input_reader.rb
# accept some name argument. if name is nil || '-',
# then use $stdin and send that to the block
# otherwise, use File.open(name, *restargs)

require 'delegate'

def input_reader(fname, *fargs)
block = Proc.new {|source|
getter = SimpleDelegator.new(source)
yield getter
getter.__setobj__(nil)
}

if fname.nil? || fname == '-' then
block[$stdin]
else
File.open(fname, *fargs) {|f| block[f]}
end
end

Would you mind explaining to me why you use SimpleDelegate above? I
would really appreciate it.

James Edward Gray II

 

[James Edward Gray II]

My use of SimpleDelegator is that I don't want a case like this:
handle = nil
input_reader("myfile") {|handle| ...}
some_func(handle)

Thank you for walking through this with me.

granted, the file ensures that things are closed off so I really don't
have to, but to go along with the idea of how things `should be' - I
used simple delegator for __set_obj__. Just design philosophy.

The only case I can think of for this mattering in the file I gave is
this:

handle = nil
input_reader(some_arg) {|handle| ...}
handle.puts "Meow Mix Please Deliver"

Hmm, but the code I saw was:

block = Proc.new {|source|
getter = SimpleDelegator.new(source)
yield getter
getter.__setobj__(nil)
}

You're worried that "getter" may have existed outside input_reader(),
in the calling code, and you want it to be immediately obvious if you
trample that value?

James Edward Gray II

 

[James Edward Gray II]

So I think that's exactly what you mean - but I just
reworded/reiterated it to make sure.

Got it. Thanks again.

James Edward Gray II