PySlice (#152)

build.zig

@@ -20,6 +20,8 @@ pub fn build(b: *std.Build) void {
 
     const pythonInc = getPythonIncludePath(python_exe, b.allocator) catch @panic("Missing python");
     const pythonLib = getPythonLibraryPath(python_exe, b.allocator) catch @panic("Missing python");
+    const pythonVer = getPythonLDVersion(python_exe, b.allocator) catch @panic("Missing python");
+    const pythonLibName = std.fmt.allocPrint(b.allocator, "python{s}", .{pythonVer}) catch @panic("Missing python");
 
     const test_step = b.step("test", "Run library tests");
     const docs_step = b.step("docs", "Generate docs");
@@ -52,7 +54,7 @@ pub fn build(b: *std.Build) void {
     main_tests.linkLibC();
     main_tests.addIncludePath(.{ .path = pythonInc });
     main_tests.addLibraryPath(.{ .path = pythonLib });
-    main_tests.linkSystemLibrary("python3.11");
+    main_tests.linkSystemLibrary(pythonLibName);
     main_tests.addAnonymousModule("pyconf", .{ .source_file = .{ .path = "./pyconf.dummy.zig" } });
 
     const run_main_tests = b.addRunArtifact(main_tests);
@@ -69,7 +71,7 @@ pub fn build(b: *std.Build) void {
     example_lib.linkLibC();
     main_tests.addIncludePath(.{ .path = pythonInc });
     main_tests.addLibraryPath(.{ .path = pythonLib });
-    main_tests.linkSystemLibrary("python3.11");
+    main_tests.linkSystemLibrary(pythonLibName);
     main_tests.addAnonymousModule("pydust", .{ .source_file = .{ .path = "pydust/src/pydust.zig" } });
     main_tests.addAnonymousModule("pyconf", .{ .source_file = .{ .path = "./pyconf.dummy.zig" } });
 
@@ -103,3 +105,12 @@ fn getPythonLibraryPath(python_exe: []const u8, allocator: std.mem.Allocator) ![
     defer allocator.free(includeResult.stderr);
     return includeResult.stdout;
 }
+
+fn getPythonLDVersion(python_exe: []const u8, allocator: std.mem.Allocator) ![]const u8 {
+    const includeResult = try std.process.Child.exec(.{
+        .allocator = allocator,
+        .argv = &.{ python_exe, "-c", "import sysconfig; print(sysconfig.get_config_var('LDVERSION'), end='')" },
+    });
+    defer allocator.free(includeResult.stderr);
+    return includeResult.stdout;
+}

pydust/src/trampoline.zig

@@ -216,6 +216,7 @@ pub fn Trampoline(comptime T: type) type {
             // Early return to handle optionals
             if (typeInfo == .Optional) {
                 const value = object orelse return null;
+                if (py.is_none(value)) return null;
                 return @as(T, try Trampoline(typeInfo.Optional.child).unwrap(value));
             }
 

pydust/src/types.zig

@@ -20,6 +20,7 @@ pub usingnamespace @import("types/list.zig");
 pub usingnamespace @import("types/long.zig");
 pub usingnamespace @import("types/module.zig");
 pub usingnamespace @import("types/obj.zig");
+pub usingnamespace @import("types/slice.zig");
 pub usingnamespace @import("types/str.zig");
 pub usingnamespace @import("types/tuple.zig");
 pub usingnamespace @import("types/type.zig");

pydust/src/types/dict.zig

@@ -189,7 +189,8 @@ test "PyDict set and get" {
     defer pd.decref();
 
     const bar = try py.PyString.create("bar");
-    try pd.setOwnedItem("foo", bar);
+    defer bar.decref();
+    try pd.setItem("foo", bar);
 
     try testing.expect(try pd.contains("foo"));
     try testing.expectEqual(@as(usize, 1), pd.length());

pydust/src/types/slice.zig

@@ -0,0 +1,60 @@
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//         http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+const std = @import("std");
+const py = @import("../pydust.zig");
+const PyObjectMixin = @import("./obj.zig").PyObjectMixin;
+const ffi = py.ffi;
+const PyError = @import("../errors.zig").PyError;
+
+/// Wrapper for Python PySlice.
+pub const PySlice = extern struct {
+    obj: py.PyObject,
+
+    pub usingnamespace PyObjectMixin("slice", "PySlice", @This());
+
+    pub fn create(start: anytype, stop: anytype, step: anytype) !PySlice {
+        // TODO(ngates): think about how to improve comptime optional handling?
+        const pystart = if (@typeInfo(@TypeOf(start)) == .Null) null else (try py.create(start)).py;
+        defer if (@typeInfo(@TypeOf(start)) != .Null) py.decref(pystart);
+        const pystop = if (@typeInfo(@TypeOf(stop)) == .Null) null else (try py.create(stop)).py;
+        defer if (@typeInfo(@TypeOf(stop)) != .Null) py.decref(pystop);
+        const pystep = if (@typeInfo(@TypeOf(step)) == .Null) null else (try py.create(step)).py;
+        defer if (@typeInfo(@TypeOf(step)) != .Null) py.decref(pystep);
+
+        const pyslice = ffi.PySlice_New(pystart, pystop, pystep) orelse return PyError.PyRaised;
+        return .{ .obj = .{ .py = pyslice } };
+    }
+
+    pub fn getStart(self: PySlice, comptime T: type) !T {
+        return try py.as(T, try self.obj.get("start"));
+    }
+
+    pub fn getStop(self: PySlice, comptime T: type) !T {
+        return try py.as(T, try self.obj.get("stop"));
+    }
+
+    pub fn getStep(self: PySlice, comptime T: type) !T {
+        return try py.as(T, try self.obj.get("step"));
+    }
+};
+
+test "PySlice" {
+    py.initialize();
+    defer py.finalize();
+
+    const range = try PySlice.create(0, 100, null);
+    defer range.decref();
+
+    try std.testing.expectEqual(@as(u64, 0), try range.getStart(u64));
+    try std.testing.expectEqual(@as(?u64, null), try range.getStep(?u64));
+}

pyproject.toml

@@ -22,7 +22,6 @@ black = "^23.9.1"
 [tool.poetry.group.dev.dependencies]
 pytest = "^7.4.0"
 ruff = "^0.0.291"
-black = "^23.9.1"
 
 [tool.poetry.group.docs.dependencies]
 # For generating docs
@@ -31,7 +30,6 @@ mkdocs-material = "^9.2.6"
 mkdocs-include-markdown-plugin = { version = "^6.0.1", python = "<3.13" }
 mike = "^1.1.2"
 
-
 [tool.poetry.group.test.dependencies]
 numpy = "^1.25.2"