Allow third party Zig modules

docs/guide/external_zig_modules.md

@@ -0,0 +1,59 @@
+# External Zig Modules
+
+In order to use third party Zig dependencies, first, we need to set pydust `self_managed` mode to `true` in `pyproject.toml`, this way, you get to manage your own `build.zig`:
+
+```toml linenums="0"
+[tool.pydust]
+self_managed = true
+```
+
+Fetch the required library with `zig fetch`. In this example we'll use [sam701/zig-toml](https://github.com/sam701/zig-toml) and [jetzig-framework/zmd](https://github.com/jetzig-framework/zmd).
+
+Fetch the libraries with `zig fetch`:
+```sh linenums="0"
+zig fetch --save git+https://github.com/jetzig-framework/zmd.git
+zig fetch --save git+https://github.com/sam701/zig-toml
+```
+
+Then, pass a list of modules to `pydust.addPythonModule`. This is an example of a `build.zig` file that uses an external Zig module:
+
+```zig title="build.zig" hl_lines="14-26 34"
+const std = @import("std");
+const py = @import("./pydust.build.zig");
+
+pub fn build(b: *std.Build) void {
+    const target = b.standardTargetOptionsQueryOnly(.{});
+    const optimize = b.standardOptimizeOption(.{});
+
+    const test_step = b.step("test", "Run library tests");
+
+    const pydust = py.addPydust(b, .{
+        .test_step = test_step,
+    });
+
+    const zmd = b.dependency("zmd", .{
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const toml = b.dependency("toml", .{
+        .target = target,
+        .optimize = optimize,
+    });
+
+    var modules: [2]std.Build.Module.Import = undefined;
+    modules[0] = std.Build.Module.Import{ .name = "zmd", .module = zmd.module("zmd") };
+    modules[1] = std.Build.Module.Import{ .name = "toml", .module = toml.module("toml") };
+
+    _ = pydust.addPythonModule(.{
+        .name = "hello",
+        .root_source_file = b.path("src/hello.zig"),
+        .limited_api = true,
+        .target = target,
+        .optimize = optimize,
+        .imports = &modules,
+    });
+}
+```
+
+Now you can import your modules from the Zig source files of you project!

mkdocs.yml

@@ -27,6 +27,7 @@ nav:
     - 'Testing': "guide/_4_testing.md"
     - 'Memory Management': "guide/_5_memory.md"
     - 'Buffer Protocol': "guide/_6_buffers.md"
+    - 'External Zig Modules': "guide/external_zig_modules.md"
 
 extra:
   social:

pydust/src/pydust.build.zig

@@ -27,6 +27,7 @@ pub const PythonModuleOptions = struct {
     target: std.Target.Query,
     optimize: std.builtin.Mode,
     main_pkg_path: ?std.Build.LazyPath = null,
+    imports: []const std.Build.Module.Import = &.{},
 
     pub fn short_name(self: *const PythonModuleOptions) [:0]const u8 {
         if (std.mem.lastIndexOfScalar(u8, self.name, '.')) |short_name_idx| {
@@ -188,6 +189,9 @@ pub const PydustStep = struct {
         lib.root_module.addImport("pydust", lib_module);
         lib.linkLibC();
         lib.linker_allow_shlib_undefined = true;
+        for (options.imports) |import| {
+            lib.root_module.addImport(import.name, import.module);
+        }
 
         // Install the shared library within the source tree
         const install = b.addInstallFileWithDir(
@@ -230,6 +234,9 @@ pub const PydustStep = struct {
         libtest.addLibraryPath(b.path(self.python_library_dir));
         // Needed to support miniconda statically linking libpython on macos
         libtest.addRPath(b.path(self.python_library_dir));
+        for (options.imports) |import| {
+            libtest.root_module.addImport(import.name, import.module);
+        }
 
         // Install the test binary
         const install_libtest = b.addInstallBinFile(