PEP 295, Interpretation of multiline string constants, Koltsov

pep-0295.txt

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+PEP: 295
+Title: Interpretation of multiline string constants
+Version: $Revision$
+Last-Modified: $Date$
+Author: yozh@mx1.ru (Stepan Koltsov)
+Status: Draft
+Type: Standards Track
+Created: 22-Jul-2002
+Python-Version: 3.0
+Post-History:
+
+Abstract
+
+    This PEP describes an interpretation of multiline string constants
+    for Python.  It suggests stripping spaces after newlines and
+    stripping a newline if it is first character after an opening
+    quotation.
+
+
+Rationale
+
+    This PEP proposes an interpretation of multiline string constants
+    in Python.  Currently, the value of string constant is all the
+    text between quotations, maybe with escape sequences substituted,
+    e.g.:
+
+        def f():
+            """
+            la-la-la
+            limona, banana
+            """
+        
+        def g():
+            return "This is \
+            string"
+        
+        print repr(f.__doc__)
+        print repr(g())
+    
+    prints:
+    
+        '\n\tla-la-la\n\tlimona, banana\n\t'
+        'This is \tstring'
+    
+    This PEP suggest two things
+
+	- ignore the first character after opening quotation, if it is
+	  newline
+	- second: ignore in string constants all spaces and tabs up to
+	  first non-whitespace character, but no more then current
+	  indentation.
+
+    After applying this, previous program will print:
+    
+        'la-la-la\nlimona, banana\n'
+        'This is string'
+    
+    To get this result, previous programs could be rewritten for
+    current Python as (note, this gives the same result with new
+    strings meaning):
+    
+        def f():
+            """\
+        la-la-la
+        limona, banana
+        """
+        
+        def g():
+            "This is \
+        string"
+    
+    Or stripping can be done with library routines at runtime (as
+    pydoc does), but this decreases program readability.
+
+
+Implementation
+
+    I'll say nothing about CPython, Jython or Python.NET.
+    
+    In original Python, there is no info about the current indentation
+    (in spaces) at compile time, so space and tab stripping should be
+    done at parse time.  Currently no flags can be passed to the
+    parser in program text (like from __future__ import xxx).  I
+    suggest enabling or disabling of this feature at Python compile
+    time depending of CPP flag Py_PARSE_MULTILINE_STRINGS.
+
+
+Alternatives
+
+    New interpretation of string constants can be implemented with flags
+    'i' and 'o' to string constants, like
+    
+        i"""
+        SELECT * FROM car
+        WHERE model = 'i525'
+        """ is in new style,
+        
+        o"""SELECT * FROM employee
+        WHERE birth < 1982
+        """ is in old style, and
+        
+        """
+        SELECT employee.name, car.name, car.price FROM employee, car
+        WHERE employee.salary * 36 > car.price
+        """ is in new style after Python-x.y.z and in old style otherwise.
+    
+    Also this feature can be disabled if string is raw, i.e. if flag 'r'
+    specified.
+
+
+Copyright
+
+    This document has been placed in the Public Domain.
+
+
+
+Local Variables:
+mode: indented-text
+indent-tabs-mode: nil
+sentence-end-double-space: t
+fill-column: 70
+End: