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Commit e7b5c5da authored by scoder's avatar scoder Committed by GitHub
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Merge pull request #2286 from gabrieldemarmiesse/compat_py2_py3 

Made code examples in the docs compatible with python 2 and 3.
parents 532bf275 82e01e1c
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docs/src/tutorial/array.rst
View file @ e7b5c5da
......@@ -25,7 +25,7 @@ Safe usage with memory views
cdef array.array a = array.array('i', [1, 2, 3])
cdef int[:] ca = a
print ca[0]
print(ca[0])
NB: the import brings the regular Python array object into the namespace
while the cimport adds functions accessible from Cython.
......@@ -51,8 +51,8 @@ functions without overhead, so long as it is typed::
cdef int no_overhead(int[:] ca):
return ca[0]
print overhead(a) # new memory view will be constructed, overhead
print no_overhead(ca) # ca is already a memory view, so no overhead
print(overhead(a)) # new memory view will be constructed, overhead
print(no_overhead(ca)) # ca is already a memory view, so no overhead
Zero-overhead, unsafe access to raw C pointer
---------------------------------------------
......@@ -69,7 +69,7 @@ right type and signedness.
cdef array.array a = array.array('i', [1, 2, 3])
# access underlying pointer:
print a.data.as_ints[0]
print(a.data.as_ints[0])
from libc.string cimport memset
memset(a.data.as_voidptr, 0, len(a) * sizeof(int))
......
docs/src/tutorial/pure.rst
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......@@ -57,7 +57,7 @@ file to be of the declared type. Thus if one has a file :file:`A.py`::
self.b = b
def foo(self, x):
print x + _helper(1.0)
print(x + _helper(1.0))
and adds :file:`A.pxd`::
......@@ -84,7 +84,7 @@ then Cython will compile the :file:`A.py` as if it had been written as follows::
self.b = b
cpdef foo(self, double x):
print x + _helper(1.0)
print(x + _helper(1.0))
Notice how in order to provide the Python wrappers to the definitions
in the :file:`.pxd`, that is, to be accessible from Python,
......@@ -312,8 +312,8 @@ Further Cython functions and declarations
::
cython.declare(n=cython.longlong)
print cython.sizeof(cython.longlong)
print cython.sizeof(n)
print(cython.sizeof(cython.longlong))
print(cython.sizeof(n))
* ``struct`` can be used to create struct types.::
......
docs/src/userguide/extension_types.rst
View file @ e7b5c5da
......@@ -14,6 +14,8 @@ statement, Cython also lets you create new built-in Python types, known as
extension types. You define an extension type using the :keyword:`cdef` class
statement. Here's an example::
from __future__ import print_function
cdef class Shrubbery:
cdef int width, height
......@@ -23,8 +25,8 @@ statement. Here's an example::
self.height = h
def describe(self):
print "This shrubbery is", self.width, \
"by", self.height, "cubits."
print("This shrubbery is", self.width,
"by", self.height, "cubits.")
As you can see, a Cython extension type definition looks a lot like a Python
class definition. Within it, you use the def statement to define methods that
......@@ -164,13 +166,13 @@ Suppose I have a method :meth:`quest` which returns an object of type :class:`Sh
To access it's width I could write::
cdef Shrubbery sh = quest()
print sh.width
print(sh.width)
which requires the use of a local variable and performs a type test on assignment.
If you *know* the return value of :meth:`quest` will be of type :class:`Shrubbery`
you can use a cast to write::
print (<Shrubbery>quest()).width
print( (<Shrubbery>quest()).width )
This may be dangerous if :meth:`quest()` is not actually a :class:`Shrubbery`, as it
will try to access width as a C struct member which may not exist. At the C level,
......@@ -178,21 +180,17 @@ rather than raising an :class:`AttributeError`, either an nonsensical result wil
returned (interpreting whatever data is at that address as an int) or a segfault
may result from trying to access invalid memory. Instead, one can write::
print (<Shrubbery?>quest()).width
print( (<Shrubbery?>quest()).width )
which performs a type check (possibly raising a :class:`TypeError`) before making the
cast and allowing the code to proceed.
To explicitly test the type of an object, use the :meth:`isinstance` method. By default,
in Python, the :meth:`isinstance` method checks the :class:`__class__` attribute of the
first argument to determine if it is of the required type. However, this is potentially
unsafe as the :class:`__class__` attribute can be spoofed or changed, but the C structure
of an extension type must be correct to access its :keyword:`cdef` attributes and call its :keyword:`cdef` methods. Cython detects if the second argument is a known extension
type and does a type check instead, analogous to Pyrex's :meth:`typecheck`.
The old behavior is always available by passing a tuple as the second parameter::
print isinstance(sh, Shrubbery) # Check the type of sh
print isinstance(sh, (Shrubbery,)) # Check sh.__class__
To explicitly test the type of an object, use the :meth:`isinstance` method.
For known builtin or extension types, Cython translates these into a
fast and safe type check that ignores changes to
the object's ``__class__`` attribute etc., so that after a successful
:meth:`isinstance` test, code can rely on the expected C structure of the
extension type and its :keyword:`cdef` attributes and methods.
.. _extension_types_and_none:
......@@ -340,16 +338,16 @@ when it is deleted.::
from cheesy import CheeseShop
shop = CheeseShop()
print shop.cheese
print(shop.cheese)
shop.cheese = "camembert"
print shop.cheese
print(shop.cheese)
shop.cheese = "cheddar"
print shop.cheese
print(shop.cheese)
del shop.cheese
print shop.cheese
print(shop.cheese)
.. sourcecode:: text
......@@ -419,21 +417,21 @@ compared to a :keyword:`cdef` method::
cdef class Parrot:
cdef void describe(self):
print "This parrot is resting."
print("This parrot is resting.")
cdef class Norwegian(Parrot):
cdef void describe(self):
Parrot.describe(self)
print "Lovely plumage!"
print("Lovely plumage!")
cdef Parrot p1, p2
p1 = Parrot()
p2 = Norwegian()
print "p1:"
print("p1:")
p1.describe()
print "p2:"
print("p2:")
p2.describe()
.. sourcecode:: text
......@@ -643,6 +641,8 @@ objects defined in the Python core or in a non-Cython extension module.
Here is an example which will let you get at the C-level members of the
built-in complex object.::
from __future__ import print_function
cdef extern from "complexobject.h":
struct Py_complex:
......@@ -654,8 +654,8 @@ built-in complex object.::
# A function which uses the above type
def spam(complex c):
print "Real:", c.cval.real
print "Imag:", c.cval.imag
print("Real:", c.cval.real)
print("Imag:", c.cval.imag)
.. note::
......
docs/src/userguide/external_C_code.rst
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......@@ -475,7 +475,7 @@ made available when you include :file:`modulename_api.h`.::
cdef api void activate(Vehicle *v):
if v.speed >= 88 and v.power >= 1.21:
print "Time travel achieved"
print("Time travel achieved")
.. sourcecode:: c
......
docs/src/userguide/fusedtypes.rst
View file @ e7b5c5da
......@@ -26,6 +26,7 @@ Quickstart
::
from __future__ import print_function
cimport cython
ctypedef fused char_or_float:
......@@ -41,8 +42,8 @@ Quickstart
cdef:
cython.char a = 127
cython.float b = 127
print 'char', plus_one(a)
print 'float', plus_one(b)
print('char', plus_one(a))
print('float', plus_one(b))
This gives::
......@@ -267,7 +268,7 @@ to figure out whether a specialization is part of another set of types
long_pointer = &i
if bunch_of_types in string_t:
print "s is a string!"
print("s is a string!")
__signatures__
==============
......
docs/src/userguide/language_basics.rst
View file @ e7b5c5da
......@@ -124,6 +124,8 @@ internally to store attributes.
Here is a simple example::
from __future__ import print_function
cdef class Shrubbery:
cdef int width, height
......@@ -133,8 +135,8 @@ Here is a simple example::
self.height = h
def describe(self):
print "This shrubbery is", self.width, \
"by", self.height, "cubits."
print("This shrubbery is", self.width,
"by", self.height, "cubits.")
You can read more about them in :ref:`extension-types`.
......@@ -194,6 +196,8 @@ Grouping multiple C declarations
If you have a series of declarations that all begin with :keyword:`cdef`, you
can group them into a :keyword:`cdef` block like this::
from __future__ import print_function
cdef:
struct Spam:
int tons
......@@ -203,7 +207,7 @@ can group them into a :keyword:`cdef` block like this::
Spam *p
void f(Spam *s):
print s.tons, "Tons of spam"
print(s.tons, "Tons of spam")
.. _cpdef:
.. _cdef:
......@@ -645,7 +649,6 @@ with ``<object>``, or a more specific builtin or extension type
the object by one, i.e. the cast returns an owned reference.
Here is an example::
from __future__ import print_function
from cpython.ref cimport PyObject
from libc.stdint cimport uintptr_t
......@@ -985,9 +988,11 @@ expression must evaluate to a Python value of type ``int``, ``long``,
::
from __future__ import print_function
cdef int a1[ArraySize]
cdef int a2[OtherArraySize]
print "I like", FavouriteFood
print("I like", FavouriteFood)
Conditional Statements
----------------------
......
docs/src/userguide/limitations.rst
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......@@ -60,4 +60,4 @@ Identity vs. equality for inferred literals
if some_runtime_expression:
b = a # creates a new Python float object
c = a # creates a new Python float object
print b is c # most likely not the same object
print(b is c) # most likely not the same object
docs/src/userguide/sharing_declarations.rst
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......@@ -101,7 +101,7 @@ uses it.
def serve():
cdef spamdish d
prepare(&d)
print "%d oz spam, filler no. %d" % (d.oz_of_spam, d.filler)
print("%d oz spam, filler no. %d" % (d.oz_of_spam, d.filler))
It is important to understand that the :keyword:`cimport` statement can only
be used to import C data types, C functions and variables, and extension
......@@ -184,11 +184,13 @@ example:
:file:`spammery.pyx`::
from __future__ import print_function
from volume cimport cube
def menu(description, size):
print description, ":", cube(size), \
"cubic metres of spam"
print(description, ":", cube(size),
"cubic metres of spam")
menu("Entree", 1)
menu("Main course", 3)
......@@ -243,7 +245,7 @@ and another module which uses it:
cdef Shrubbing.Shrubbery sh
sh = Shrubbing.standard_shrubbery()
print "Shrubbery size is %d x %d" % (sh.width, sh.length)
print("Shrubbery size is %d x %d" % (sh.width, sh.length))
One would then need to compile both of these modules, e.g. using
......
docs/src/userguide/wrapping_CPlusPlus.rst
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......@@ -428,7 +428,7 @@ Cython uses a bracket syntax for templating. A simple example for wrapping C++ v
cdef vector[int].iterator it = v.begin()
while it != v.end():
print deref(it)
print(deref(it))
inc(it)
del v
......@@ -447,8 +447,8 @@ the template parameter list following the function name::
cdef extern from "<algorithm>" namespace "std":
T max[T](T a, T b)
print max[long](3, 4)
print max(1.5, 2.5) # simple template argument deduction
print(max[long](3, 4))
print(max(1.5, 2.5)) # simple template argument deduction
Standard library
......@@ -467,7 +467,7 @@ For example::
for i in range(10):
vect.push_back(i)
for i in range(10):
print vect[i]
print(vect[i])
The pxd files in ``/Cython/Includes/libcpp`` also work as good examples on
how to declare C++ classes.
......
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