pybind11/example/issues.py
Wenzel Jakob 86d825f330 Redesigned virtual call mechanism and user-facing syntax (breaking change!)
Sergey Lyskov pointed out that the trampoline mechanism used to override
virtual methods from within Python caused unnecessary overheads when
instantiating the original (i.e. non-extended) class.

This commit removes this inefficiency, but some syntax changes were
needed to achieve this. Projects using this features will need to make a
few changes:

In particular, the example below shows the old syntax to instantiate a
class with a trampoline:

class_<TrampolineClass>("MyClass")
    .alias<MyClass>()
    ....

This is what should be used now:

class_<MyClass, std::unique_ptr<MyClass, TrampolineClass>("MyClass")
    ....

Importantly, the trampoline class is now specified as the *third*
argument to the class_ template, and the alias<..>() call is gone. The
second argument with the unique pointer is simply the default holder
type used by pybind11.
2016-05-26 13:36:24 +02:00

75 lines
1.6 KiB
Python

#!/usr/bin/env python
from __future__ import print_function
import sys
sys.path.append('.')
from example.issues import print_cchar, print_char
from example.issues import DispatchIssue, dispatch_issue_go
from example.issues import Placeholder, return_vec_of_reference_wrapper
from example.issues import iterator_passthrough
from example.issues import ElementList, ElementA, print_element
from example.issues import expect_float, expect_int
from example.issues import A, call_f
import gc
print_cchar("const char *")
print_char('c')
class PyClass1(DispatchIssue):
def dispatch(self):
print("Yay..")
class PyClass2(DispatchIssue):
def dispatch(self):
try:
super(PyClass2, self).dispatch()
except Exception as e:
print("Failed as expected: " + str(e))
p = PyClass1()
dispatch_issue_go(p)
b = PyClass2()
dispatch_issue_go(b)
print(return_vec_of_reference_wrapper(Placeholder(4)))
print(list(iterator_passthrough(iter([3, 5, 7, 9, 11, 13, 15]))))
el = ElementList()
for i in range(10):
el.add(ElementA(i))
gc.collect()
for i, v in enumerate(el.get()):
print("%i==%i, " % (i, v.value()), end='')
print()
try:
print_element(None)
except Exception as e:
print("Failed as expected: " + str(e))
try:
print(expect_int(5.2))
except Exception as e:
print("Failed as expected: " + str(e))
print(expect_float(12))
class B(A):
def __init__(self):
super(B, self).__init__()
def f(self):
print("In python f()")
print("C++ version")
a = A()
call_f(a)
print("Python version")
b = B()
call_f(b)