xorn/src/cpython/guile/scm2py.c

   1 /* Copyright (C) 2013-2020 Roland Lutz
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; either version 2 of the License, or
   6    (at your option) any later version.
   7
   8    This program is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11    GNU General Public License for more details.
  12
  13    You should have received a copy of the GNU General Public License
  14    along with this program; if not, write to the Free Software Foundation,
  15    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  16
  17 #include "module.h"
  18
  19
  20 PyObject *scm2py(SCM value)
  21 {
  22         if (value == NULL)
  23                 return NULL;
  24         if (scm_is_eq(value, SCM_UNSPECIFIED)) {
  25                 Py_INCREF(Py_None);
  26                 return Py_None;
  27         }
  28         if (scm_is_exact_integer(value))
  29                 return PyInt_FromLong(scm_to_long(value));
  30         if (scm_is_real(value))
  31                 return PyFloat_FromDouble(scm_to_double(value));
  32         if (scm_is_bool(value)) {
  33                 PyObject *result = scm_to_bool(value) ? Py_True : Py_False;
  34                 Py_INCREF(result);
  35                 return result;
  36         }
  37         if (scm_is_null(value))
  38                 return PyTuple_New(0);
  39         if (scm_is_string(value)) {
  40                 size_t len = 0;
  41                 char *s = scm_to_utf8_stringn(value, &len);
  42                 PyObject *result = PyUnicode_FromStringAndSize(s, len);
  43                 free(s);
  44                 return result;
  45         }
  46         if (scm_is_pair(value)) {
  47                 unsigned int len = scm_to_uint(scm_length(value));
  48                 PyObject *result = PyTuple_New(len);
  49                 scm_dynwind_begin(0);
  50                 scm_dynwind_unwind_handler(
  51                         (void (*)(void *))Py_DecRef, result, 0);
  52                 unsigned int i;
  53                 for (i = 0; i < len; i++) {
  54                         PyObject *item = scm2py(scm_car(value));
  55                         if (item == NULL) {
  56                                 scm_dynwind_end();
  57                                 Py_DECREF(result);
  58                                 return NULL;
  59                         }
  60                         PyTuple_SET_ITEM(result, i, item);
  61                         value = scm_cdr(value);
  62                 }
  63                 scm_dynwind_end();
  64                 return result;
  65         }
  66         if (scm_to_bool(scm_procedure_p(value))) {
  67                 SCM ptr = scm_assq_ref(gsubr_alist, value);
  68                 if (!scm_is_false(ptr)) {
  69                         PyObject *result = scm_to_pointer(ptr);
  70                         Py_INCREF(result);
  71                         return result;
  72                 }
  73                 Procedure *result =
  74                         (Procedure *)ProcedureType.tp_alloc(&ProcedureType, 0);
  75                 if (result == NULL)
  76                         return NULL;
  77                 result->proc = value;
  78                 return (PyObject *)result;
  79         }
  80
  81         char *msg = scm_to_utf8_stringn(
  82                 scm_simple_format(
  83                         SCM_BOOL_F,
  84                         scm_from_utf8_string(
  85                                 "Guile expression ~S doesn't have a "
  86                                 "corresponding Python value"),
  87                         scm_list_1(value)), NULL);
  88         PyErr_SetString(PyExc_TypeError, msg);
  89         free(msg);
  90         return NULL;
  91 }