Clean API and add docs

build.zig

@@ -21,6 +21,9 @@ pub fn build(b: *std.Build) void {
     // target and optimize options) will be listed when running `zig build --help`
     // in this directory.
 
+    // Get default install step (called with `zig build` or `zig build install`)
+    const install_step = b.getInstallStep();
+
     // This creates a module, which represents a collection of source files alongside
     // some compilation options, such as optimization mode and linked system libraries.
     // Zig modules are the preferred way of making Zig code available to consumers.
@@ -41,6 +44,22 @@ pub fn build(b: *std.Build) void {
         .target = target,
     });
 
+    // Only used to generate the documentation
+    const zaprus_lib = b.addLibrary(.{
+        .name = "zaprus",
+        .root_module = mod,
+    });
+
+    const docs_step = b.step("doc", "Emit documentation");
+    const docs_install = b.addInstallDirectory(.{
+        .install_dir = .prefix,
+        .install_subdir = "docs",
+        .source_dir = zaprus_lib.getEmittedDocs(),
+    });
+
+    docs_step.dependOn(&docs_install.step);
+    install_step.dependOn(docs_step);
+
     // Create static library
     const lib = b.addLibrary(.{
         .name = "zaprus",