factor out redundancy in std::string -> Python object helper code

Cython/Utility/CppConvert.pyx

@@ -24,31 +24,15 @@ cdef extern from *:
     cdef cppclass string "{{type}}":
         char* data()
         size_t size()
-    cdef object __Pyx_PyObject_FromStringAndSize(char*, size_t)
-    cdef object __Pyx_PyBytes_FromStringAndSize(char*, size_t)
-    cdef object __Pyx_PyByteArray_FromStringAndSize(char*, size_t)
-    cdef object __Pyx_PyStr_FromStringAndSize(char*, size_t)
-    cdef object __Pyx_PyUnicode_FromStringAndSize(char*, size_t)
 
-@cname("{{cname}}")
-cdef inline object {{cname}}(const string& s):
-    return __Pyx_PyObject_FromStringAndSize(s.data(), s.size())
-
-@cname("{{cname.replace("PyObject", "PyUnicode", 1)}}")
-cdef inline object {{cname.replace("PyObject", "PyUnicode", 1)}}(const string& s):
-    return __Pyx_PyUnicode_FromStringAndSize(s.data(), s.size())
-
-@cname("{{cname.replace("PyObject", "PyStr", 1)}}")
-cdef inline object {{cname.replace("PyObject", "PyStr", 1)}}(const string& s):
-    return __Pyx_PyStr_FromStringAndSize(s.data(), s.size())
-
-@cname("{{cname.replace("PyObject", "PyBytes", 1)}}")
-cdef inline object {{cname.replace("PyObject", "PyBytes", 1)}}(const string& s):
-    return __Pyx_PyBytes_FromStringAndSize(s.data(), s.size())
+{{for py_type in ['PyObject', 'PyUnicode', 'PyStr', 'PyBytes', 'PyByteArray']}}
+cdef extern from *:
+    cdef object __Pyx_{{py_type}}_FromStringAndSize(char*, size_t)
 
-@cname("{{cname.replace("PyObject", "PyByteArray", 1)}}")
-cdef inline object {{cname.replace("PyObject", "PyByteArray", 1)}}(const string& s):
-    return __Pyx_PyByteArray_FromStringAndSize(s.data(), s.size())
+@cname("{{cname.replace("PyObject", py_type, 1)}}")
+cdef inline object {{cname.replace("PyObject", py_type, 1)}}(const string& s):
+    return __Pyx_{{py_type}}_FromStringAndSize(s.data(), s.size())
+{{endfor}}
 
 
 #################### vector.from_py ####################