#2630: Implement PEP 3138.

The repr() of a string now contains printable Unicode characters unescaped.
The new ascii() builtin can be used to get a repr() with only ASCII characters in it.

PEP and patch were written by Atsuo Ishimoto.

3 files changed, 22 insertions, 2 deletions

diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 875eea0..a420974 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -91,6 +91,14 @@ are always available.  They are listed here in alphabetical order.
           return False
 
 
+.. function:: ascii(object)
+
+   As :func:`repr`, return a string containing a printable representation of an
+   object, but escape the non-ASCII characters in the string returned by
+   :func:`repr` using ``\x``, ``\u`` or ``\U`` escapes.  This generates a string
+   similar to that returned by :func:`repr` in Python 2.
+
+
 .. function:: bin(x)
 
    Convert an integer number to a binary string. The result is a valid Python
diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
index 27c3fb4..0dd520e 100644
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -774,6 +774,17 @@ functions based on regular expressions.
    least one cased character, false otherwise.
 
 
+.. method:: str.isprintable()
+
+   Return true if all characters in the string are printable or the string is
+   empty, false otherwise.  Nonprintable characters are those characters defined
+   in the Unicode character database as "Other" or "Separator", excepting the
+   ASCII space (0x20) which is considered printable.  (Note that printable
+   characters in this context are those which should not be escaped when
+   :func:`repr` is invoked on a string.  It has no bearing on the handling of
+   strings written to :data:`sys.stdout` or :data:`sys.stderr`.)
+
+
 .. method:: str.isspace()
 
    Return true if there are only whitespace characters in the string and there is
diff --git a/Doc/library/string.rst b/Doc/library/string.rst
index a5c3a81..668a530 100644
--- a/Doc/library/string.rst
+++ b/Doc/library/string.rst
@@ -229,8 +229,9 @@ as a string, overriding its own definition of formatting.  By converting the
 value to a string before calling :meth:`__format__`, the normal formatting logic
 is bypassed.
 
-Two conversion flags are currently supported: ``'!s'`` which calls :func:`str`
-on the value, and ``'!r'`` which calls :func:`repr`.
+Three conversion flags are currently supported: ``'!s'`` which calls :func:`str`
+on the value, ``'!r'`` which calls :func:`repr` and ``'!a'`` which calls
+:func:`ascii`.
 
 Some examples::