Type initialiser accepts sequences, stores internally as tuples. Add tests which try to break things.

src/runtime/python/expr.c

@@ -23,16 +23,24 @@ Type_init(TypeObject *self, PyObject *args, PyObject *kwds)
     PyObject* hypos;
     PyObject* name;
     PyObject* exprs;
-    if (!PyArg_ParseTuple(args, "O!UO!", &PyList_Type, &hypos, &name, &PyList_Type, &exprs)) {
+    if (!PyArg_ParseTuple(args, "OUO", &hypos, &name, &exprs)) {
+        return -1;
+    }
+    if (!PySequence_Check(hypos)) {
+        PyErr_SetString(PyExc_TypeError, "hypotheses must be iterable");
+        return -1;
+    }
+    if (!PySequence_Check(exprs)) {
+        PyErr_SetString(PyExc_TypeError, "expressions must be a sequence");
         return -1;
     }
 
-    for (Py_ssize_t i = 0; i < PyList_Size(hypos); i++) {
-        // if (!PyObject_TypeCheck(PyList_GetItem(hypos, i), &pgf_HypoType)) {
+    for (Py_ssize_t i = 0; i < PySequence_Size(hypos); i++) {
+        // if (!PyObject_TypeCheck(PySequence_GetItem(hypos, i), &pgf_HypoType)) {
         //     PyErr_SetString(PyExc_TypeError, "invalid hypo in Type initialisation");
         //     return -1;
         // }
-        PyObject *tup = PyList_GetItem(hypos, i);
+        PyObject *tup = PySequence_GetItem(hypos, i);
         if (!PyObject_TypeCheck(tup, &PyTuple_Type)) {
             PyErr_SetString(PyExc_TypeError, "hypothesis must be a tuple");
             return -1;
@@ -51,15 +59,15 @@ Type_init(TypeObject *self, PyObject *args, PyObject *kwds)
         }
     }
 
-    for (Py_ssize_t i = 0; i < PyList_Size(exprs); i++) {
-        if (!PyObject_TypeCheck(PyList_GetItem(exprs, i), &pgf_ExprType)) {
+    for (Py_ssize_t i = 0; i < PySequence_Size(exprs); i++) {
+        if (!PyObject_TypeCheck(PySequence_GetItem(exprs, i), &pgf_ExprType)) {
             PyErr_SetString(PyExc_TypeError, "invalid expression in Type initialisation");
             return -1;
         }
     }
-    self->hypos = hypos;
+    self->hypos = PySequence_Tuple(hypos);
     self->name = name;
-    self->exprs = exprs;
+    self->exprs = PySequence_Tuple(exprs);
     Py_INCREF(self->hypos);
     Py_INCREF(self->name);
     Py_INCREF(self->exprs);
@@ -94,18 +102,18 @@ Type_richcompare(TypeObject *t1, PyObject *p2, int op)
 
     if (PyUnicode_Compare(t1->name, t2->name) != 0) goto done;
 
-    if (PyList_Size(t1->hypos) != PyList_Size(t2->hypos)) goto done;
-    for (Py_ssize_t n = 0; n < PyList_Size(t1->hypos); n++) {
-        PyObject *h1 = PyList_GetItem(t1->hypos, n);
-        PyObject *h2 = PyList_GetItem(t2->hypos, n);
+    if (PyTuple_Size(t1->hypos) != PyTuple_Size(t2->hypos)) goto done;
+    for (Py_ssize_t n = 0; n < PyTuple_Size(t1->hypos); n++) {
+        PyObject *h1 = PyTuple_GetItem(t1->hypos, n);
+        PyObject *h2 = PyTuple_GetItem(t2->hypos, n);
         if (!PyObject_RichCompareBool(h1, h2, Py_EQ))
             goto done;
     }
 
-    if (PyList_Size(t1->exprs) != PyList_Size(t2->exprs)) goto done;
-    for (Py_ssize_t n = 0; n < PyList_Size(t1->exprs); n++) {
-        PyObject *e1 = PyList_GetItem(t1->exprs, n);
-        PyObject *e2 = PyList_GetItem(t2->exprs, n);
+    if (PyTuple_Size(t1->exprs) != PyTuple_Size(t2->exprs)) goto done;
+    for (Py_ssize_t n = 0; n < PyTuple_Size(t1->exprs); n++) {
+        PyObject *e1 = PyTuple_GetItem(t1->exprs, n);
+        PyObject *e2 = PyTuple_GetItem(t2->exprs, n);
         if (!PyObject_RichCompareBool(e1, e2, Py_EQ))
             goto done;
     }
@@ -128,9 +136,9 @@ static PyMethodDef Type_methods[] = {
 };
 
 static PyMemberDef Type_members[] = {
-    {"hypos", T_OBJECT_EX, offsetof(TypeObject, hypos), READONLY, "list of hypotheses in the type signature"},
+    {"hypos", T_OBJECT_EX, offsetof(TypeObject, hypos), READONLY, "hypotheses in the type signature"},
     {"cat", T_OBJECT_EX, offsetof(TypeObject, name), READONLY, "name of the category"},
-    {"exprs", T_OBJECT_EX, offsetof(TypeObject, exprs), READONLY, "list of indices for the category"},
+    {"exprs", T_OBJECT_EX, offsetof(TypeObject, exprs), READONLY, "indices for the category"},
     {NULL}  /* Sentinel */
 };
 

src/runtime/python/expr.h

@@ -8,9 +8,9 @@
 
 typedef struct {
     PyObject_HEAD
-    PyObject *hypos; // PyListObject of PyTupleObject: (PyBool, PyUnicodeObject, TypeObject)
+    PyObject *hypos; // PyTupleObject of PyTupleObject: (PyBool, PyUnicodeObject, TypeObject)
     PyObject *name;  // PyUnicodeObject
-    PyObject *exprs; // PyListObject of ExprObject
+    PyObject *exprs; // PyTupleObject of ExprObject
 } TypeObject;
 
 PyTypeObject pgf_TypeType;

src/runtime/python/ffi.c

@@ -61,18 +61,18 @@ PyUnicode_FromPgfText(PgfText *text)
 }
 
 PgfTypeHypo *
-PyList_AsHypos(PyObject *pylist, Py_ssize_t *n_hypos)
+PySequence_AsHypos(PyObject *pyseq, Py_ssize_t *n_hypos)
 {
-    if (!PyList_Check(pylist)) {
-        PyErr_SetString(PyExc_TypeError, "hypotheses must be a list");
+    if (!PySequence_Check(pyseq)) {
+        PyErr_SetString(PyExc_TypeError, "hypotheses must be a sequence");
         return NULL;
     }
-    Py_ssize_t n = PyList_Size(pylist);
+    Py_ssize_t n = PySequence_Size(pyseq);
     *n_hypos = n;
     PgfTypeHypo *hypos = PyMem_RawMalloc(sizeof(PgfTypeHypo)*n);
 
     for (Py_ssize_t i = 0; i < n; i++) {
-        // PyObject *item = PyList_GetItem(pylist, i);
+        // PyObject *item = PySequence_GetItem(pyseq, i);
         // if (!PyObject_TypeCheck(item, &pgf_HypoType)) {
         //     PyErr_SetString(PyExc_TypeError, "hypothesis must be of type Hypo");
         //     return NULL;
@@ -82,7 +82,7 @@ PyList_AsHypos(PyObject *pylist, Py_ssize_t *n_hypos)
         // hypos[i].cid = PyUnicode_AsPgfText(hypo->cid);
         // hypos[i].type = (PgfType) hypo->type;
 
-        PyObject *tup = PyList_GetItem(pylist, i);
+        PyObject *tup = PySequence_GetItem(pyseq, i);
         if (!PyTuple_Check(tup)) {
             PyErr_SetString(PyExc_TypeError, "hypothesis must be a tuple");
             return NULL;
@@ -317,12 +317,12 @@ dtyp(PgfUnmarshaller *this, int n_hypos, PgfTypeHypo *hypos, PgfText *cat, int n
 {
     TypeObject *pytype = (TypeObject *)pgf_TypeType.tp_alloc(&pgf_TypeType, 0);
 
-    pytype->hypos = PyList_FromHypos(hypos, n_hypos);
+    pytype->hypos = PySequence_Tuple(PyList_FromHypos(hypos, n_hypos));
     pytype->name = PyUnicode_FromStringAndSize(cat->text, cat->size);
-    pytype->exprs = PyList_New(n_exprs);
+    pytype->exprs = PyTuple_New(n_exprs);
     for (int i = 0; i < n_exprs; i++) {
         PyObject *expr = (PyObject *)exprs[i];
-        PyList_SetItem(pytype->exprs, i, expr);
+        PyTuple_SetItem(pytype->exprs, i, expr);
         Py_INCREF(expr);
     }
 
@@ -454,19 +454,20 @@ match_type(PgfMarshaller *this, PgfUnmarshaller *u, PgfType ty)
     TypeObject *type = (TypeObject *)ty;
 
     Py_ssize_t n_hypos;
-    PgfTypeHypo *hypos = PyList_AsHypos(type->hypos, &n_hypos);
-    if (PyErr_Occurred())
+    PgfTypeHypo *hypos = PySequence_AsHypos(type->hypos, &n_hypos);
+    if (hypos == NULL) {
         return 0;
+    }
 
     PgfText *cat = PyUnicode_AsPgfText(type->name);
     if (cat == NULL) {
         return 0;
     }
 
-    Py_ssize_t n_exprs = PyList_Size(type->exprs);
+    Py_ssize_t n_exprs = PySequence_Size(type->exprs);
     PgfExpr exprs[n_exprs];
     for (Py_ssize_t i = 0; i < n_exprs; i++) {
-        exprs[i] = (PgfExpr)PyList_GetItem(type->exprs, i);
+        exprs[i] = (PgfExpr)PySequence_GetItem(type->exprs, i);
         Py_INCREF(exprs[i]);
     }
 

src/runtime/python/ffi.h

@@ -20,7 +20,7 @@ PgfText *CString_AsPgfText(const char *s, size_t size);
 PgfText *PyUnicode_AsPgfText(PyObject *pystr);
 PyObject *PyUnicode_FromPgfText(PgfText *text);
 
-PgfTypeHypo *PyList_AsHypos(PyObject *pylist, Py_ssize_t *n_hypos);
+PgfTypeHypo *PySequence_AsHypos(PyObject *pyseq, Py_ssize_t *n_hypos);
 PyObject *PyList_FromHypos(PgfTypeHypo *hypos, const size_t n_hypos);
 
 PgfPrintContext *PyList_AsPgfPrintContext(PyObject *pylist);

src/runtime/python/tests/test_basic.py

@@ -219,9 +219,11 @@ def test_Type_getters():
     h0 = mkDepHypo("x", Type([], "N", []))
     e0 = ExprVar(0)
     type = Type([h0], "N", [e0])
-    assert type.hypos == [h0]
+    assert len(type.hypos) == 1
+    assert type.hypos[0] == h0
     assert type.cat == "N"
-    assert type.exprs == [e0]
+    assert len(type.exprs) == 1
+    assert type.exprs[0] == e0
     with pytest.raises(AttributeError):
         type.fake
 

src/runtime/python/tests/test_breaking.py

@@ -0,0 +1,35 @@
+import os
+import pytest
+from pgf import *
+
+@pytest.fixture(scope="module")
+def PGF():
+    return readPGF("../haskell/tests/basic.pgf")
+
+
+def test_init_Type_tuples():
+    hypos = [mkDepHypo("x", Type([], "N", []))]
+    exprs = [ExprVar(0)]
+    ty = Type(tuple(hypos), "P", tuple(exprs))
+    assert str(ty) == "(x : N) -> P x"
+
+def test_init_Type_lists():
+    hypos = [mkDepHypo("x", Type([], "N", []))]
+    exprs = [ExprVar(0)]
+    ty = Type(hypos, "P", exprs)
+    assert str(ty) == "(x : N) -> P x"
+
+def test_Type_modify_shallow():
+    hypos = [(BIND_TYPE_EXPLICIT, "x", Type([], "N", []))]
+    exprs = [ExprVar(0)]
+    ty = Type(hypos, "P", exprs)
+    hypos.append(None)
+    assert str(ty) == "(x : N) -> P x"
+
+def test_Type_modify_deep():
+    hypos = [(BIND_TYPE_EXPLICIT, "x", Type([], "N", []))]
+    exprs = [ExprVar(0)]
+    ty = Type(hypos, "P", exprs)
+    with pytest.raises(AttributeError):
+        hypos[0][2].exprs.append(None)
+        assert str(ty) == "(x : N) -> P x"

src/runtime/python/transactions.c

@@ -184,13 +184,17 @@ Transaction_createCategory(TransactionObject *self, PyObject *args)
     Py_ssize_t size;
     PyObject *hypos;
     prob_t prob = 0.0;
-    if (!PyArg_ParseTuple(args, "s#O!f", &s, &size, &PyList_Type, &hypos, &prob))
+    if (!PyArg_ParseTuple(args, "s#Of", &s, &size, &hypos, &prob))
         return NULL;
+    if (!PySequence_Check(hypos)) {
+        PyErr_SetString(PyExc_TypeError, "context must be a sequence");
+        return NULL;
+    }
 
     PgfText *catname = CString_AsPgfText(s, size);
 
     Py_ssize_t n_hypos;
-    PgfTypeHypo *context = PyList_AsHypos(hypos, &n_hypos);
+    PgfTypeHypo *context = PySequence_AsHypos(hypos, &n_hypos);
     if (PyErr_Occurred()) {
         FreePgfText(catname);
         return NULL;