Issue #2335: Backport set literals syntax from Python 3.x.

1 files changed, 66 insertions, 0 deletions

diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index 61e7427380..4f10aa077a 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -188,6 +188,10 @@ static char *Dict_fields[]={
         "keys",
         "values",
 };
+static PyTypeObject *Set_type;
+static char *Set_fields[]={
+        "elts",
+};
 static PyTypeObject *ListComp_type;
 static char *ListComp_fields[]={
         "elt",
@@ -718,6 +722,8 @@ static int init_types(void)
         if (!IfExp_type) return 0;
         Dict_type = make_type("Dict", expr_type, Dict_fields, 2);
         if (!Dict_type) return 0;
+        Set_type = make_type("Set", expr_type, Set_fields, 1);
+        if (!Set_type) return 0;
         ListComp_type = make_type("ListComp", expr_type, ListComp_fields, 2);
         if (!ListComp_type) return 0;
         GeneratorExp_type = make_type("GeneratorExp", expr_type,
@@ -1590,6 +1596,20 @@ Dict(asdl_seq * keys, asdl_seq * values, int lineno, int col_offset, PyArena
 }
 
 expr_ty
+Set(asdl_seq * elts, int lineno, int col_offset, PyArena *arena)
+{
+        expr_ty p;
+        p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
+        if (!p)
+                return NULL;
+        p->kind = Set_kind;
+        p->v.Set.elts = elts;
+        p->lineno = lineno;
+        p->col_offset = col_offset;
+        return p;
+}
+
+expr_ty
 ListComp(expr_ty elt, asdl_seq * generators, int lineno, int col_offset,
          PyArena *arena)
 {
@@ -2566,6 +2586,15 @@ ast2obj_expr(void* _o)
                         goto failed;
                 Py_DECREF(value);
                 break;
+        case Set_kind:
+                result = PyType_GenericNew(Set_type, NULL, NULL);
+                if (!result) goto failed;
+                value = ast2obj_list(o->v.Set.elts, ast2obj_expr);
+                if (!value) goto failed;
+                if (PyObject_SetAttrString(result, "elts", value) == -1)
+                        goto failed;
+                Py_DECREF(value);
+                break;
         case ListComp_kind:
                 result = PyType_GenericNew(ListComp_type, NULL, NULL);
                 if (!result) goto failed;
@@ -4860,6 +4889,42 @@ obj2ast_expr(PyObject* obj, expr_ty* out, PyArena* arena)
                 if (*out == NULL) goto failed;
                 return 0;
         }
+        isinstance = PyObject_IsInstance(obj, (PyObject*)Set_type);
+        if (isinstance == -1) {
+                return 1;
+        }
+        if (isinstance) {
+                asdl_seq* elts;
+
+                if (PyObject_HasAttrString(obj, "elts")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "elts");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Set field \"elts\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        elts = asdl_seq_new(len, arena);
+                        if (elts == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(elts, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"elts\" missing from Set");
+                        return 1;
+                }
+                *out = Set(elts, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
         isinstance = PyObject_IsInstance(obj, (PyObject*)ListComp_type);
         if (isinstance == -1) {
                 return 1;
@@ -6351,6 +6416,7 @@ init_ast(void)
             return;
         if (PyDict_SetItemString(d, "IfExp", (PyObject*)IfExp_type) < 0) return;
         if (PyDict_SetItemString(d, "Dict", (PyObject*)Dict_type) < 0) return;
+        if (PyDict_SetItemString(d, "Set", (PyObject*)Set_type) < 0) return;
         if (PyDict_SetItemString(d, "ListComp", (PyObject*)ListComp_type) < 0)
             return;
         if (PyDict_SetItemString(d, "GeneratorExp",