[break] Refactor call API

pydust/src/builtins.zig

@@ -71,6 +71,54 @@ pub fn callable(object: anytype) bool {
     return ffi.PyCallable_Check(obj.py) == 1;
 }
 
+/// Call a callable object with no arguments.
+///
+/// If the result is a new reference, then as always the caller is responsible for calling decref on it.
+/// That means for new references the caller should ask for a return type that they are unable to decref,
+/// for example []const u8.
+pub fn call0(comptime T: type, object: anytype) !T {
+    const result = ffi.PyObject_CallNoArgs(py.object(object).py) orelse return PyError.PyRaised;
+    return try py.as(T, result);
+}
+
+/// Call a callable object with the given arguments.
+///
+/// If the result is a new reference, then as always the caller is responsible for calling decref on it.
+/// That means for new references the caller should ask for a return type that they are unable to decref,
+/// for example []const u8.
+pub fn call(comptime ReturnType: type, object: anytype, args: anytype, kwargs: anytype) !ReturnType {
+    const pyobj = py.object(object);
+
+    var argsPy: py.PyTuple = undefined;
+    if (@typeInfo(@TypeOf(args)) == .Optional and args == null) {
+        argsPy = try py.PyTuple.new(0);
+    } else {
+        argsPy = try py.PyTuple.checked(try py.create(args));
+    }
+    defer argsPy.decref();
+
+    // TODO(ngates): avoid creating empty dict for kwargs
+    var kwargsPy: py.PyDict = undefined;
+    if (@typeInfo(@TypeOf(kwargs)) == .Optional and kwargs == null) {
+        kwargsPy = try py.PyDict.new();
+    } else {
+        // Annoyingly our trampoline turns an empty kwargs struct into a PyTuple.
+        // This will be fixed by #94
+        const kwobj = try py.create(kwargs);
+        if (try py.len(kwobj) == 0) {
+            kwobj.decref();
+            kwargsPy = try py.PyDict.new();
+        } else {
+            kwargsPy = try py.PyDict.checked(kwobj);
+        }
+    }
+    defer kwargsPy.decref();
+
+    // Note, the caller is responsible for returning a result type that they are able to decref.
+    const result = ffi.PyObject_Call(pyobj.py, argsPy.obj.py, kwargsPy.obj.py) orelse return PyError.PyRaised;
+    return try py.as(ReturnType, result);
+}
+
 /// Convert an object into a dictionary. Equivalent of Python dict(o).
 pub fn dict(object: anytype) !py.PyDict {
     const Dict: py.PyObject = .{ .py = @alignCast(@ptrCast(&ffi.PyDict_Type)) };

pydust/src/modules.zig

@@ -124,11 +124,11 @@ fn Slots(comptime definition: type) type {
                 const pySubmodDef: *ffi.PyModuleDef = @ptrCast((try submodDef.init()).py);
 
                 // Create a dumb ModuleSpec with a name attribute using types.SimpleNamespace
-                const SimpleNamespace = try py.importFrom("types", "SimpleNamespace");
-
+                const types = try py.import("types");
+                defer types.decref();
                 const pyname = try py.PyString.create(name);
                 defer pyname.decref();
-                const spec = try SimpleNamespace.call(.{}, .{ .name = pyname });
+                const spec = try types.call(py.PyObject, "SimpleNamespace", .{}, .{ .name = pyname });
                 defer spec.decref();
 
                 const submod: py.PyObject = .{ .py = ffi.PyModule_FromDefAndSpec(pySubmodDef, spec.py) orelse return PyError.PyRaised };

pydust/src/types/error.zig

@@ -166,25 +166,14 @@ const PyExc = struct {
                 );
                 defer py.allocator.free(code);
 
-                // Compilation should succeed, but execution will fail.
-                const filename = try py.allocator.dupeZ(u8, line_info.file_name);
-                defer py.allocator.free(filename);
-                const compiled = ffi.Py_CompileString(code.ptr, filename.ptr, ffi.Py_file_input) orelse continue;
-                defer py.decref(compiled);
-
                 // Import the compiled code as a module and invoke the failing function
-                const module_name = try py.allocator.dupeZ(u8, symbol_info.compile_unit_name);
-                defer py.allocator.free(module_name);
-                const fake_module: py.PyObject = .{
-                    .py = ffi.PyImport_ExecCodeModule(module_name.ptr, compiled) orelse continue,
-                };
+                const fake_module = try py.PyModule.fromCode(code, line_info.file_name, symbol_info.compile_unit_name);
                 defer fake_module.decref();
 
                 const func_name = try py.allocator.dupeZ(u8, symbol_info.symbol_name);
                 defer py.allocator.free(func_name);
-                const fake_function = try fake_module.get(func_name);
-                _ = fake_function.call(.{}, .{}) catch null;
-                defer fake_function.decref();
+
+                _ = fake_module.obj.call(void, func_name, .{}, .{}) catch null;
 
                 // Grab our forced exception info.
                 // We can ignore qtype and qvalue, we just want to get the traceback object.

pydust/src/types/obj.zig

@@ -33,45 +33,20 @@ pub const PyObject = extern struct {
         return name.asSlice();
     }
 
-    /// Call this object without any arguments.
-    pub fn call0(self: PyObject) !PyObject {
-        return .{ .py = ffi.PyObject_CallNoArgs(self.py) orelse return PyError.PyRaised };
-    }
-
     /// Call this object with the given args and kwargs.
-    pub fn call(self: PyObject, args: anytype, kwargs: anytype) !PyObject {
-        var argsPy: py.PyTuple = undefined;
-        if (@typeInfo(@TypeOf(args)) == .Optional and args == null) {
-            argsPy = try py.PyTuple.new(0);
-        } else {
-            argsPy = try py.PyTuple.checked(try py.create(args));
-        }
-        defer argsPy.decref();
-
-        // FIXME(ngates): avoid creating empty dict for kwargs
-        var kwargsPy: py.PyDict = undefined;
-        if (@typeInfo(@TypeOf(kwargs)) == .Optional and kwargs == null) {
-            kwargsPy = try py.PyDict.new();
-        } else {
-            const kwobj = try py.create(kwargs);
-            if (try py.len(kwobj) == 0) {
-                kwobj.decref();
-                kwargsPy = try py.PyDict.new();
-            } else {
-                kwargsPy = try py.PyDict.checked(kwobj);
-            }
-        }
-        defer kwargsPy.decref();
-
-        // We _must_ return a PyObject to the user to let them handle the lifetime of the object.
-        const result = ffi.PyObject_Call(self.py, argsPy.obj.py, kwargsPy.obj.py) orelse return PyError.PyRaised;
-        return PyObject{ .py = result };
+    pub fn call(self: PyObject, comptime T: type, method: [:0]const u8, args: anytype, kwargs: anytype) !T {
+        const methodObj = try self.get(method);
+        return py.call(T, methodObj, args, kwargs);
     }
 
-    pub fn get(self: PyObject, attr: [:0]const u8) !PyObject {
+    pub fn get(self: PyObject, attr: [:0]const u8) !py.PyObject {
         return .{ .py = ffi.PyObject_GetAttrString(self.py, attr) orelse return PyError.PyRaised };
     }
 
+    pub fn getAs(self: PyObject, comptime T: type, attr: [:0]const u8) !T {
+        return try py.as(T, try self.get(attr));
+    }
+
     // See: https://docs.python.org/3/c-api/buffer.html#buffer-request-types
     pub fn getBuffer(self: py.PyObject, flags: c_int) !py.PyBuffer {
         if (ffi.PyObject_CheckBuffer(self.py) != 1) {
@@ -151,11 +126,6 @@ test "call" {
     defer py.finalize();
 
     const pow = try py.importFrom("math", "pow");
-    const result = try pow.call(.{ 2, 3 }, .{});
-
-    if (py.PyFloat.checkedCast(result)) |f| {
-        try std.testing.expectEqual(f.as(f32), 8.0);
-    }
-
-    try std.testing.expectEqual(@as(f32, 8.0), try py.as(f32, result));
+    const result = try py.call(f32, pow, .{ 2, 3 }, .{});
+    try std.testing.expectEqual(@as(f32, 8.0), result);
 }

pydust/src/types/slice.zig

@@ -36,15 +36,15 @@ pub const PySlice = extern struct {
     }
 
     pub fn getStart(self: PySlice, comptime T: type) !T {
-        return try py.as(T, try self.obj.get("start"));
+        return try self.obj.getAs(T, "start");
     }
 
     pub fn getStop(self: PySlice, comptime T: type) !T {
-        return try py.as(T, try self.obj.get("stop"));
+        return try try self.obj.getAs(T, "stop");
     }
 
     pub fn getStep(self: PySlice, comptime T: type) !T {
-        return try py.as(T, try self.obj.get("step"));
+        return try self.obj.getAs(T, "step");
     }
 };
 

pydust/src/types/type.zig

@@ -49,11 +49,13 @@ test "PyType" {
     py.initialize();
     defer py.finalize();
 
-    const StringIO = try PyType.checked(try py.importFrom("io", "StringIO"));
-    defer StringIO.decref();
+    const io = try py.import("io");
+    defer io.decref();
+
+    const StringIO = try io.getAs(py.PyType, "StringIO");
     try std.testing.expectEqualSlices(u8, "StringIO", try (try StringIO.name()).asSlice());
 
-    const sio = try StringIO.obj.call0();
+    const sio = try py.call0(py.PyObject, StringIO);
     defer sio.decref();
     const sioType = try py.type_(sio);
     try std.testing.expectEqualSlices(u8, "StringIO", try (try sioType.name()).asSlice());