2 files changed, 115 insertions, 0 deletions

diff --git a/examples/hello-zig/src/main.zig b/examples/hello-zig/src/main.zig
new file mode 100644
index 0000000..74eb590
--- /dev/null
+++ b/examples/hello-zig/src/main.zig
@@ -0,0 +1,32 @@
+const std = @import("std");
+const hello_zig = @import("hello_zig");
+
+pub fn main() !void {
+    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+    defer arena.deinit();
+
+    const allocator = arena.allocator();
+    const args = try std.process.argsAlloc(allocator);
+    const name = if (args.len > 1) args[1] else "Nova";
+
+    var greeter = hello_zig.Greeter{
+        .name = name,
+        .punctuation = '!',
+    };
+
+    const stdout = std.fs.File.stdout().deprecatedWriter();
+    try greeter.write(stdout, .verbose);
+
+    const sample_values = [_]i32{ -3, -2, 0, 1, 2, 3, 4 };
+    var squares = try hello_zig.collectEvenSquares(allocator, &sample_values);
+    defer squares.deinit(allocator);
+
+    std.debug.print("even squares: {any}\n", .{squares.items});
+}
+
+test "main module can compute a summary" {
+    const greeting = try hello_zig.describeNumber(std.testing.allocator, 42);
+    defer std.testing.allocator.free(greeting);
+
+    try std.testing.expect(std.mem.startsWith(u8, greeting, "positive"));
+}
diff --git a/examples/hello-zig/src/root.zig b/examples/hello-zig/src/root.zig
new file mode 100644
index 0000000..f6600ac
--- /dev/null
+++ b/examples/hello-zig/src/root.zig
@@ -0,0 +1,83 @@
+const std = @import("std");
+
+pub const OutputStyle = enum {
+    compact,
+    verbose,
+};
+
+pub const NumberKind = union(enum) {
+    negative: i64,
+    zero,
+    positive: u64,
+};
+
+pub const Greeter = struct {
+    name: []const u8,
+    punctuation: u8 = '!',
+
+    pub fn write(self: Greeter, writer: anytype, style: OutputStyle) !void {
+        switch (style) {
+            .compact => try writer.print("hello, {s}{c}\n", .{ self.name, self.punctuation }),
+            .verbose => {
+                try writer.print(
+                    \\hello, {s}{c}
+                    \\this sample is here to exercise Zig syntax support in Nova.
+                    \\
+                , .{ self.name, self.punctuation });
+            },
+        }
+    }
+};
+
+pub fn classifyNumber(value: i64) NumberKind {
+    if (value == 0) return .zero;
+    if (value < 0) return .{ .negative = value };
+    return .{ .positive = @intCast(value) };
+}
+
+pub fn describeNumber(allocator: std.mem.Allocator, value: i64) ![]u8 {
+    return switch (classifyNumber(value)) {
+        .zero => std.fmt.allocPrint(allocator, "zero", .{}),
+        .negative => |negative| std.fmt.allocPrint(allocator, "negative({d})", .{negative}),
+        .positive => |positive| std.fmt.allocPrint(allocator, "positive({d})", .{positive}),
+    };
+}
+
+pub fn collectEvenSquares(
+    allocator: std.mem.Allocator,
+    values: []const i32,
+) !std.ArrayList(i32) {
+    var result: std.ArrayList(i32) = .empty;
+    errdefer result.deinit(allocator);
+
+    for (values) |value| {
+        if (@mod(value, 2) != 0) continue;
+        try result.append(allocator, value * value);
+    }
+
+    return result;
+}
+
+test "classifyNumber covers the main branches" {
+    try std.testing.expectEqual(NumberKind{ .negative = -5 }, classifyNumber(-5));
+    try std.testing.expectEqual(NumberKind.zero, classifyNumber(0));
+    try std.testing.expectEqual(NumberKind{ .positive = 9 }, classifyNumber(9));
+}
+
+test "collectEvenSquares keeps only even numbers" {
+    const values = [_]i32{ -4, -3, 0, 1, 2, 7 };
+    var result = try collectEvenSquares(std.testing.allocator, &values);
+    defer result.deinit(std.testing.allocator);
+
+    try std.testing.expectEqualSlices(i32, &.{ 16, 0, 4 }, result.items);
+}
+
+test "Greeter.write renders verbose output" {
+    var list: std.ArrayList(u8) = .empty;
+    defer list.deinit(std.testing.allocator);
+
+    const writer = list.writer(std.testing.allocator);
+    try (Greeter{ .name = "Zig" }).write(writer, .verbose);
+
+    try std.testing.expect(std.mem.indexOf(u8, list.items, "exercise Zig syntax support") != null);
+}