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gvanrossumgvanrossum
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Add the 'bool' type and its values 'False' and 'True', as described in
PEP 285. Everything described in the PEP is here, and there is even some documentation. I had to fix 12 unit tests; all but one of these were printing Boolean outcomes that changed from 0/1 to False/True. (The exception is test_unicode.py, which did a type(x) == type(y) style comparison. I could've fixed that with a single line using issubtype(x, type(y)), but instead chose to be explicit about those places where a bool is expected. Still to do: perhaps more documentation; change standard library modules to return False/True from predicates.
1 parent e9c0358 commit 77f6a65

29 files changed

Lines changed: 494 additions & 383 deletions

‎Doc/lib/libfuncs.tex‎

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@@ -77,6 +77,16 @@ \section{Built-in Functions \label{built-in-funcs}}
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to \code{\var{function}(*\var{args}, **\var{keywords})}.
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\end{funcdesc}
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\begin{funcdesc}{bool}{x}
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Convert a value to a Boolean, using the standard truth testing
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procedure. If \code{x} is false, this returns \code{False};
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otherwise it returns \code{True}. \code{bool} is also a class,
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which is a subclass of \code{int}. Class \code{bool} cannot be
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subclassed further. Its only instances are \code{False} and
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\code{True}.
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\indexii{Boolean}{type}
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\end{funcdesc}
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\begin{funcdesc}{buffer}{object\optional{, offset\optional{, size}}}
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The \var{object} argument must be an object that supports the buffer
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call interface (such as strings, arrays, and buffers). A new buffer

‎Doc/lib/libstdtypes.tex‎

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@@ -2,10 +2,8 @@ \section{Built-in Types \label{types}}
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The following sections describe the standard types that are built into
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the interpreter. These are the numeric types, sequence types, and
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several others, including types themselves. There is no explicit
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Boolean type; use integers instead.
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several others, including types themselves.
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\indexii{built-in}{types}
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\indexii{Boolean}{type}
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Some operations are supported by several object types; in particular,
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all objects can be compared, tested for truth value, and converted to
@@ -30,6 +28,9 @@ \subsection{Truth Value Testing \label{truth}}
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\item \code{None}
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\withsubitem{(Built-in object)}{\ttindex{None}}
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31+
\item \code{False}
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\withsubitem{(Built-in object)}{\ttindex{False}}
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\item zero of any numeric type, for example, \code{0}, \code{0L},
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\code{0.0}, \code{0j}.
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@@ -50,11 +51,12 @@ \subsection{Truth Value Testing \label{truth}}
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\index{true}
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Operations and built-in functions that have a Boolean result always
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return \code{0} for false and \code{1} for true, unless otherwise
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stated. (Important exception: the Boolean operations
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\samp{or}\opindex{or} and \samp{and}\opindex{and} always return one of
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their operands.)
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return \code{0} or \code{False} for false and \code{1} or \code{True}
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for true, unless otherwise stated. (Important exception: the Boolean
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operations \samp{or}\opindex{or} and \samp{and}\opindex{and} always
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return one of their operands.)
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\index{False}
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\index{True}
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\subsection{Boolean Operations \label{boolean}}
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@@ -68,7 +70,7 @@ \subsection{Boolean Operations \label{boolean}}
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{if \var{x} is false, then \var{x}, else \var{y}}{(1)}
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\hline
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\lineiii{not \var{x}}
71-
{if \var{x} is false, then \code{1}, else \code{0}}{(2)}
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{if \var{x} is false, then \code{True}, else \code{False}}{(2)}
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\end{tableiii}
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\opindex{and}
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\opindex{or}
@@ -161,15 +163,18 @@ \subsection{Comparisons \label{comparisons}}
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\subsection{Numeric Types \label{typesnumeric}}
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164-
There are four numeric types: \dfn{plain integers}, \dfn{long integers},
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There are four distinct numeric types: \dfn{plain integers},
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\dfn{long integers},
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\dfn{floating point numbers}, and \dfn{complex numbers}.
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In addition, Booleans are a subtype of plain integers.
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Plain integers (also just called \dfn{integers})
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are implemented using \ctype{long} in C, which gives them at least 32
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bits of precision. Long integers have unlimited precision. Floating
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point numbers are implemented using \ctype{double} in C. All bets on
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their precision are off unless you happen to know the machine you are
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working with.
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\obindex{numeric}
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\obindex{Boolean}
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\obindex{integer}
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\obindex{long integer}
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\obindex{floating point}
@@ -1389,6 +1394,22 @@ \subsubsection{The Ellipsis Object \label{bltin-ellipsis-object}}
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13901395
It is written as \code{Ellipsis}.
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1397+
\subsubsection{Boolean Values}
1398+
1399+
Boolean values are the two constant objects \code{False} and
1400+
\code{True}. They are used to represent truth values (although other
1401+
values can also be considered false or true). In numeric contexts
1402+
(for example when used as the argument to an arithmetic operator),
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they behave like the integers 0 and 1, respectively. The built-in
1404+
function \function{bool()} can be used to cast any value to a Boolean,
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if the value can be interpreted as a truth value (see section Truth
1406+
Value Testing above).
1407+
1408+
They are written as \code{False} and \code{True}, respectively.
1409+
\index{False}
1410+
\index{True}
1411+
\indexii{Boolean}{values}
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\subsubsection{Internal Objects \label{typesinternal}}
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‎Doc/ref/ref3.tex‎

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@@ -162,7 +162,7 @@ \section{The standard type hierarchy\label{types}}
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These represent elements from the mathematical set of whole numbers.
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\obindex{integer}
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165-
There are two types of integers:
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There are three types of integers:
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\begin{description}
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@@ -187,6 +187,17 @@ \section{The standard type hierarchy\label{types}}
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an infinite string of sign bits extending to the left.
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\obindex{long integer}
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\item[Booleans]
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These represent the truth values False and True. The two objects
192+
representing the values False and True are the only Boolean objects.
193+
The Boolean type is a subtype of plain integers, and Boolean values
194+
behave like the values 0 and 1, respectively, in almost all contexts,
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the exception being that when converted to a string, the strings
196+
\code{"False"} or \code{"True"} are returned, respectively.
197+
\obindex{Boolean}
198+
\ttindex{False}
199+
\ttindex{True}
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\end{description} % Integers
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192203
The rules for integer representation are intended to give the most
@@ -222,6 +233,7 @@ \section{The standard type hierarchy\label{types}}
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223234
\end{description} % Numbers
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\item[Sequences]
226238
These represent finite ordered sets indexed by non-negative numbers.
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The built-in function \function{len()}\bifuncindex{len} returns the
@@ -1074,8 +1086,10 @@ \subsection{Basic customization\label{customization}}
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\end{methoddesc}
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\begin{methoddesc}[object]{__nonzero__}{self}
1077-
Called to implement truth value testing; should return \code{0} or
1078-
\code{1}. When this method is not defined, \method{__len__()} is
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Called to implement truth value testing, and the built-in operation
1090+
\code{bool()}; should return \code{False} or \code{True}, or their
1091+
integer equivalents \code{0} or \code{1}.
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When this method is not defined, \method{__len__()} is
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called, if it is defined (see below). If a class defines neither
10801094
\method{__len__()} nor \method{__nonzero__()}, all its instances are
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considered true.

‎Include/Python.h‎

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@@ -79,6 +79,7 @@
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#include "unicodeobject.h"
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#include "intobject.h"
82+
#include "boolobject.h"
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#include "longobject.h"
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#include "floatobject.h"
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#ifndef WITHOUT_COMPLEX

‎Include/intobject.h‎

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@@ -38,21 +38,6 @@ extern DL_IMPORT(PyObject *) PyInt_FromLong(long);
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extern DL_IMPORT(long) PyInt_AsLong(PyObject *);
3939
extern DL_IMPORT(long) PyInt_GetMax(void);
4040

41-
42-
/*
43-
False and True are special intobjects used by Boolean expressions.
44-
All values of type Boolean must point to either of these; but in
45-
contexts where integers are required they are integers (valued 0 and 1).
46-
Hope these macros don't conflict with other people's.
47-
48-
Don't forget to apply Py_INCREF() when returning True or False!!!
49-
*/
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extern DL_IMPORT(PyIntObject) _Py_ZeroStruct, _Py_TrueStruct; /* Don't use these directly */
52-
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#define Py_False ((PyObject *) &_Py_ZeroStruct)
54-
#define Py_True ((PyObject *) &_Py_TrueStruct)
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/* Macro, trading safety for speed */
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#define PyInt_AS_LONG(op) (((PyIntObject *)(op))->ob_ival)
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‎Include/object.h‎

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@@ -531,8 +531,8 @@ extern DL_IMPORT(long) _Py_RefTotal;
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#define Py_DECREF(op) \
532532
if (--_Py_RefTotal, 0 < (--((op)->ob_refcnt))) ; \
533533
else if (0 == (op)->ob_refcnt) _Py_Dealloc( (PyObject*)(op)); \
534-
else (void)fprintf( stderr, "%s:%i negative ref count %i\n", \
535-
__FILE__, __LINE__, (op)->ob_refcnt)
534+
else ((void)fprintf( stderr, "%s:%i negative ref count %i\n", \
535+
__FILE__, __LINE__, (op)->ob_refcnt), abort())
536536
#else /* !Py_REF_DEBUG */
537537

538538
#ifdef COUNT_ALLOCS

‎Lib/difflib.py‎

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@@ -976,11 +976,11 @@ def IS_LINE_JUNK(line, pat=re.compile(r"\s*#?\s*$").match):
976976
Examples:
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978978
>>> IS_LINE_JUNK('\n')
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1
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True
980980
>>> IS_LINE_JUNK(' # \n')
981-
1
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True
982982
>>> IS_LINE_JUNK('hello\n')
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0
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False
984984
"""
985985

986986
return pat(line) is not None
@@ -992,13 +992,13 @@ def IS_CHARACTER_JUNK(ch, ws=" \t"):
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Examples:
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994994
>>> IS_CHARACTER_JUNK(' ')
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1
995+
True
996996
>>> IS_CHARACTER_JUNK('\t')
997-
1
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True
998998
>>> IS_CHARACTER_JUNK('\n')
999-
0
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False
10001000
>>> IS_CHARACTER_JUNK('x')
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0
1001+
False
10021002
"""
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10041004
return ch in ws

‎Lib/doctest.py‎

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@@ -545,19 +545,19 @@ def is_private(prefix, base):
545545
does not both begin and end with (at least) two underscores.
546546
547547
>>> is_private("a.b", "my_func")
548-
0
548+
False
549549
>>> is_private("____", "_my_func")
550-
1
550+
True
551551
>>> is_private("someclass", "__init__")
552-
0
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False
553553
>>> is_private("sometypo", "__init_")
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1
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True
555555
>>> is_private("x.y.z", "_")
556-
1
556+
True
557557
>>> is_private("_x.y.z", "__")
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0
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False
559559
>>> is_private("", "") # senseless but consistent
560-
0
560+
False
561561
"""
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563563
return base[:1] == "_" and not base[:2] == "__" == base[-2:]

‎Lib/pickle.py‎

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@@ -101,6 +101,9 @@ def __init__(self, value):
101101
EMPTY_TUPLE = ')'
102102
SETITEMS = 'u'
103103
BINFLOAT = 'G'
104+
TRUE = 'Z'
105+
FALSE = 'z'
106+
104107

105108
__all__.extend([x for x in dir() if re.match("[A-Z][A-Z0-9_]+$",x)])
106109
del x
@@ -256,6 +259,13 @@ def save_none(self, object):
256259
self.write(NONE)
257260
dispatch[NoneType] = save_none
258261

262+
def save_bool(self, object):
263+
if object:
264+
self.write(TRUE)
265+
else:
266+
self.write(FALSE)
267+
dispatch[bool] = save_bool
268+
259269
def save_int(self, object):
260270
if self.bin:
261271
# If the int is small enough to fit in a signed 4-byte 2's-comp
@@ -629,6 +639,14 @@ def load_none(self):
629639
self.append(None)
630640
dispatch[NONE] = load_none
631641

642+
def load_false(self):
643+
self.append(False)
644+
dispatch[FALSE] = load_false
645+
646+
def load_true(self):
647+
self.append(True)
648+
dispatch[TRUE] = load_true
649+
632650
def load_int(self):
633651
data = self.readline()
634652
try:

‎Lib/test/output/test_augassign‎

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@@ -4,14 +4,14 @@ test_augassign
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6
55
[1, 2, 3, 4, 1, 2, 3, 4]
66
[1, 2, 1, 2, 3]
7-
1
8-
1
9-
1
7+
True
8+
True
9+
True
1010
11
11-
1
11+
True
1212
12
13-
1
14-
1
13+
True
14+
True
1515
13
1616
__add__ called
1717
__radd__ called

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