[Python-Dev] Re: Re: file() or open()? (original) (raw)

Terry Reedy tjreedy at udel.edu
Sat Jul 10 07:05:59 CEST 2004

"orbitz" <orbitz at ezabel.com> wrote in message news:40EC61DD.50704 at ezabel.com... Terry Reedy wrote:

François Pinard" <pinard at iro.umontreal.ca> wrote in message

perceived the introduction of `file()' as a nice cleanup in Python.

As a user, so did I. I like the cosistency of using file along with int, tuple, list, dict, type, (and did I leave out something), and all user classes as constructors of instances of themselves.

[top post moved down before responding to give better context]

I considered more as the action being performed. I'm opening something,

Are you, really? I understand opening a door, gate, hinged lid, file folder, gun stock, clam, fist, or book. All of these involve a hinge motion, usually reversible. Opening a drawer uses a reversible sliding motion. Opening a can, walnut, or geode involves an irreversible cut or smash. I do not see much analogy of any of these motions with the action of open/type().

If you say that they all give access, I could just as well say that you are unlocking, leasing, or learning something or acquiring a permission.

In my view, file/open() (in read mode) asks the interpreter to construct a Python object that corresponds to and connects and gives access to the external non-PyObject data (byte) stream indicated by the name/locator string so that I may bring part or all of that data into the Python dataspace as one or more Python objects (initially strings). The host-system specifics of the access mechanism is beyond the purview of Python itself.

So, if you ignore the constructor analogy and want an action name, I think proxy, connect, access, lease, or even setup might be better. In short, the action is

py_data_object = proxy(non_pyob_data_access_info)

Should socket.socket() have been socket.open because it 'opens' a communication channel (in the process of creating a socket object)? For me, this analogy works at least as well as 'opening' a document (see below).

in this case a file.

Is it, really? If one thinks in terms of the offices and desks, a file is a container that keeps a series of related cards, papers, or documents in order. In this context, a series of bytes, usually represents and is better called a paper or document. People write documents and put them into files. But when documents are called 'files, files have to be called something else, like 'directory' or 'folder' .

If by file one means a sequence or string of bytes in analogy with a file of people, (also from the Latin filum == thread, as in filament), then opening the file/sequence would seem to mean opening one or more spaces in the sequence. In chess and war, opening a file has the similar meaning of removing enemy occupants from a series of spaces.

And now I have an object which has been opened, I can perform operations on it, and when I'm done I close it.

I use the proxy to access non-Python data and then release the proxy. What, if anything, the host system does upon release is outside the purview of Python.

In a previous post, Guido justified 'open' on the basis that applications 'open' 'files'. However, in every such application I can think of at the moment, 'open' means 'read the data and convert it to one of the application's internal native formats, even if it was written in a different format by another application. In other words, app.open(path) == file(path).read().convert(filetype(path)). Conversely, one never opens a file before saveing a fresh new document; one just saves-as. So Python's open() is quite different from the app usage of 'open'.

Terry J. Reedy

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