[Python-checkins] r53833 - peps/trunk/pep-0000.txt peps/trunk/pep-3111.txt
nick.coghlan
python-checkins at python.org
Tue Feb 20 14:57:07 CET 2007
Author: nick.coghlan
Date: Tue Feb 20 14:57:06 2007
New Revision: 53833
Added:
peps/trunk/pep-3111.txt (contents, props changed)
Modified:
peps/trunk/pep-0000.txt
Log:
Formally record December's acceptance of the raw_input() -> input() renaming.
Modified: peps/trunk/pep-0000.txt
==============================================================================
--- peps/trunk/pep-0000.txt (original)
+++ peps/trunk/pep-0000.txt Tue Feb 20 14:57:06 2007
@@ -82,6 +82,7 @@
SA 3107 Function Annotations Winter, Lownds
SA 3109 Raising Exceptions in Python 3000 Winter
SA 3110 Catching Exceptions in Python 3000 Winter
+ SA 3111 Simple input built-in in Python 3000 Roberge
Open PEPs (under consideration)
@@ -453,6 +454,7 @@
I 3108 Standard Library Reorganization Cannon
SA 3109 Raising Exceptions in Python 3000 Winter
SA 3110 Catching Exceptions in Python 3000 Winter
+ SA 3111 Simple input built-in in Python 3000 Roberge
Key
@@ -544,6 +546,7 @@
Reifschneider, Sean jafo-pep at tummy.com
Reis, Christian R. kiko at async.com.br
Riehl, Jonathan jriehl at spaceship.com
+ Roberge, André andre.roberge at gmail.com
van Rossum, Guido (GvR) guido at python.org
van Rossum, Just (JvR) just at letterror.com
Sajip, Vinay vinay_sajip at red-dove.com
Added: peps/trunk/pep-3111.txt
==============================================================================
--- (empty file)
+++ peps/trunk/pep-3111.txt Tue Feb 20 14:57:06 2007
@@ -0,0 +1,162 @@
+PEP: 3111
+Title: Simple input built-in in Python 3000
+Version: $Revision$
+Last-Modified: $Date$
+Author: André Roberge <andre.roberge at gmail.com >
+Status: Draft
+Type: Standards Track
+Content-Type: text/x-rst
+Created: 13-Sep-2006
+Python-Version: 3.0
+Post-History: 22-Dec-2006
+
+
+Abstract
+========
+
+Input and output are core features of computer programs. Currently,
+Python provides a simple means of output through the print keyword
+and two simple means of interactive input through the input()
+and raw_input() built-in functions.
+
+Python 3.0 will introduce various incompatible changes with previous
+Python versions[1]. Among the proposed changes, print will become a built-in
+function, print(), while input() and raw_input() would be removed completely
+from the built-in namespace, requiring importing some module to provide
+even the most basic input capability.
+
+This PEP proposes that Python 3.0 retains some simple interactive user
+input capability, equivalent to raw_input(), within the built-in namespace.
+
+It was accepted by the BDFL in December 2006 [5].
+
+
+Motivation
+==========
+
+With its easy readability and its support for many programming styles
+(e.g. procedural, object-oriented, etc.) among others, Python is perhaps
+the best computer language to use in introductory programming classes.
+Simple programs often need to provide information to the user (output)
+and to obtain information from the user (interactive input).
+Any computer language intended to be used in an educational setting should
+provide straightforward methods for both output and interactive input.
+
+The current proposals for Python 3.0 [1] include a simple output pathway
+via a built-in function named print(), but a more complicated method for
+input [e.g. via sys.stdin.readline()], one that requires importing an external
+module. Current versions of Python (pre-3.0) include raw_input() as a
+built-in function. With the availability of such a function, programs that
+require simple input/output can be written from day one, without requiring
+discussions of importing modules, streams, etc.
+
+
+Rationale
+=========
+
+Current built-in functions, like input() and raw_input(), are found to be
+extremely useful in traditional teaching settings. (For more details,
+see [2] and the discussion that followed.)
+While the BDFL has clearly stated [3] that input() was not to be kept in
+Python 3000, he has also stated that he was not against revising the
+decision of killing raw_input().
+
+raw_input() provides a simple mean to ask a question and obtain a response
+from a user. The proposed plans for Python 3.0 would require the replacement
+of the single statement::
+
+ name = raw_input("What is your name?")
+
+by the more complicated::
+
+ import sys
+ print("What is your name?")
+ same = sys.stdin.readline()
+
+However, from the point of view of many Python beginners and educators, the
+use of sys.stdin.readline() presents the following problems:
+
+1. Compared to the name "raw_input", the name "sys.stdin.readline()"
+is clunky and inelegant.
+
+2. The names "sys" and "stdin" have no meaning for most beginners,
+who are mainly interested in *what* the function does, and not *where*
+in the package structure it is located. The lack of meaning also makes
+it difficult to remember:
+is it "sys.stdin.readline()", or " stdin.sys.readline()"?
+To a programming novice, there is not any obvious reason to prefer
+one over the other. In contrast, functions simple and direct names like
+print, input, and raw_input, and open are easier to remember.
+
+3. The use of "." notation is unmotivated and confusing to many beginners.
+For example, it may lead some beginners to think "." is a standard
+character that could be used in any identifier.
+
+4. There is an asymmetry with the print function: why is print not called
+sys.stdout.print()?
+
+
+Specification
+=============
+
+The existing ``raw_input()`` function will be renamed to ``input()``.
+
+The Python 2 to 3 conversion tool will replace calls to ``input()`` with
+``eval(input())`` and ``raw_input()`` with ``input()``.
+
+
+Naming Discussion
+=================
+
+With ``input()`` effectively removed from the language, the name ``raw_input()``
+makes much less sense and alternatives should be considered. The
+various possibilities mentioned in various forums include::
+
+ ask()
+ ask_user()
+ get_string()
+ input() # initially rejected by BDFL, later accepted
+ prompt()
+ read()
+ user_input()
+ get_response()
+
+While it was initially rejected by the BDFL, it has been suggested that the most
+direct solution would be to rename "raw_input" to "input" in Python 3000.
+The main objection is that Python 2.x already has a function named "input",
+and, even though it is not going to be included in Python 3000,
+having a built-in function with the same name but different semantics may
+confuse programmers migrating from 2.x to 3000. Certainly, this is no problem
+for beginners, and the scope of the problem is unclear for more experienced
+programmers, since raw_input(), while popular with many, is not in
+universal use. In this instance, the good it does for beginners could be
+seen to outweigh the harm it does to experienced programmers -
+although it could cause confusion for people reading older books or tutorials.
+
+The rationale for accepting the renaming can be found here [4].
+
+
+References
+==========
+
+.. [1] PEP 3100, Miscellaneous Python 3.0 Plans, Kuchling, Cannon
+ http://www.python.org/dev/peps/pep-3100/
+
+.. [2] The fate of raw_input() in Python 3000
+ http://mail.python.org/pipermail/edu-sig/2006-September/006967.html
+
+.. [3] Educational aspects of Python 3000
+ http://mail.python.org/pipermail/python-3000/2006-September/003589.html
+
+.. [4] Rationale for going with the straight renaming
+ http://mail.python.org/pipermail/python-3000/2006-December/005249.html
+
+.. [5] BDFL acceptance of the PEP
+ http://mail.python.org/pipermail/python-3000/2006-December/005257.html
+
+Copyright
+=========
+
+This document has been placed in the public domain.
+
+
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