[Pyrex] Pyrex generates broken code when calling a function immediately on the result of a C function call

[Stefan Behnel]

Hi,

Pyrex 0.9.3.1 generates broken code for the following statement:

-----------------------------
    return _parseMemoryDocument(text, __DEFAULT_HTML_PARSER).getroot()
-----------------------------

_parseMemoryDocument is a C function, the type of getroot seems to be
unimportant (C or Python). The resulting C code is

-----------------------------
__pyx_1 = ((PyObject
*)__pyx_f_5etree__parseMemoryDocument(__pyx_v_text,((PyObject
*)__pyx_v_5etree___DEFAULT_HTML_PARSER))); if (!__pyx_1) {__pyx_filename =
__pyx_f[0]; __pyx_lineno = 1203; goto __pyx_L1;}

__pyx_2 = ((struct __pyx_vtabstruct_5etree__Document
*)__pyx_f_5etree__parseMemoryDocument(__pyx_v_text,((PyObject
*)__pyx_v_5etree___DEFAULT_HTML_PARSER))->__pyx_vtab)->getroot(__pyx_f_5etree__parseMemoryDocument(__pyx_v_text,((PyObject
*)__pyx_v_5etree___DEFAULT_HTML_PARSER))); if (!__pyx_2) {__pyx_filename =
__pyx_f[0]; __pyx_lineno = 1203; goto __pyx_L1;}
-----------------------------

As this shows, the C function is called three times. The work-around is to
separate the two function calls and to store the intermediate result in a
variable. This generates the following (expected) code:

-----------------------------
__pyx_1 = ((PyObject
*)__pyx_f_5etree__parseMemoryDocument(__pyx_v_text,((PyObject
*)__pyx_v_5etree___DEFAULT_HTML_PARSER))); if (!__pyx_1) {__pyx_filename =
__pyx_f[0]; __pyx_lineno = 1203; goto __pyx_L1;}
Py_DECREF(((PyObject *)__pyx_v_doc));
__pyx_v_doc = __pyx_1;
__pyx_1 = 0;

__pyx_1 = ((struct __pyx_vtabstruct_5etree__Document
*)__pyx_v_doc->__pyx_vtab)->getroot(__pyx_v_doc); if (!__pyx_1)
{__pyx_filename = __pyx_f[0]; __pyx_lineno = 1204; goto __pyx_L1;}
__pyx_r = __pyx_1;
-----------------------------

The fix would be to replace the second and third call by __pyx_1, which is
correctly calculated in the first line.

Stefan