random testing

build.zig

@@ -1,33 +1,11 @@
 const std = @import("std");
 
-// Although this function looks imperative, note that its job is to
-// declaratively construct a build graph that will be executed by an external
-// runner.
 pub fn build(b: *std.Build) void {
-    // Standard target options allows the person running `zig build` to choose
-    // what target to build for. Here we do not override the defaults, which
-    // means any target is allowed, and the default is native. Other options
-    // for restricting supported target set are available.
     const target = b.standardTargetOptions(.{});
-
-    // Standard optimization options allow the person running `zig build` to select
-    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
-    // set a preferred release mode, allowing the user to decide how to optimize.
     const optimize = b.standardOptimizeOption(.{});
+    const opts = .{ .target = target, .optimize = optimize };
 
-    const lib = b.addStaticLibrary(.{
+    const json = b.dependency("json", opts).module("json");
-        .name = "learnzig",
-        // In this case the main source file is merely a path, however, in more
-        // complicated build scripts, this could be a generated file.
-        .root_source_file = .{ .path = "src/root.zig" },
-        .target = target,
-        .optimize = optimize,
-    });
-
-    // This declares intent for the library to be installed into the standard
-    // location when the user invokes the "install" step (the default step when
-    // running `zig build`).
-    b.installArtifact(lib);
 
     const exe = b.addExecutable(.{
         .name = "learnzig",
@@ -35,57 +13,24 @@ pub fn build(b: *std.Build) void {
         .target = target,
         .optimize = optimize,
     });
-
+    exe.root_module.addImport("json", json);
-    // This declares intent for the executable to be installed into the
-    // standard location when the user invokes the "install" step (the default
-    // step when running `zig build`).
     b.installArtifact(exe);
 
-    // This *creates* a Run step in the build graph, to be executed when another
-    // step is evaluated that depends on it. The next line below will establish
-    // such a dependency.
     const run_cmd = b.addRunArtifact(exe);
-
-    // By making the run step depend on the install step, it will be run from the
-    // installation directory rather than directly from within the cache directory.
-    // This is not necessary, however, if the application depends on other installed
-    // files, this ensures they will be present and in the expected location.
     run_cmd.step.dependOn(b.getInstallStep());
-
-    // This allows the user to pass arguments to the application in the build
-    // command itself, like this: `zig build run -- arg1 arg2 etc`
     if (b.args) |args| {
         run_cmd.addArgs(args);
     }
 
-    // This creates a build step. It will be visible in the `zig build --help` menu,
-    // and can be selected like this: `zig build run`
-    // This will evaluate the `run` step rather than the default, which is "install".
     const run_step = b.step("run", "Run the app");
     run_step.dependOn(&run_cmd.step);
 
-    // Creates a step for unit testing. This only builds the test executable
-    // but does not run it.
-    const lib_unit_tests = b.addTest(.{
-        .root_source_file = .{ .path = "src/root.zig" },
-        .target = target,
-        .optimize = optimize,
-    });
-
-    const run_lib_unit_tests = b.addRunArtifact(lib_unit_tests);
-
     const exe_unit_tests = b.addTest(.{
         .root_source_file = .{ .path = "src/main.zig" },
         .target = target,
         .optimize = optimize,
     });
-
     const run_exe_unit_tests = b.addRunArtifact(exe_unit_tests);
-
-    // Similar to creating the run step earlier, this exposes a `test` step to
-    // the `zig build --help` menu, providing a way for the user to request
-    // running the unit tests.
     const test_step = b.step("test", "Run unit tests");
-    test_step.dependOn(&run_lib_unit_tests.step);
     test_step.dependOn(&run_exe_unit_tests.step);
 }

build.zig.zon

@@ -15,37 +15,11 @@
     // Once all dependencies are fetched, `zig build` no longer requires
     // internet connectivity.
     .dependencies = .{
-        // See `zig fetch --save <url>` for a command-line interface for adding dependencies.
+        .json = .{
-        //.example = .{
+            .url = "git+https://github.com/getty-zig/json.git#main",
-        //    // When updating this field to a new URL, be sure to delete the corresponding
+            .hash = "1220a6a7706fa609ce63e2bf61812515f6ab45273397ca591f925a32e7e507cb7cec",
-        //    // `hash`, otherwise you are communicating that you expect to find the old hash at
+        },
-        //    // the new URL.
-        //    .url = "https://example.com/foo.tar.gz",
-        //
-        //    // This is computed from the file contents of the directory of files that is
-        //    // obtained after fetching `url` and applying the inclusion rules given by
-        //    // `paths`.
-        //    //
-        //    // This field is the source of truth; packages do not come from a `url`; they
-        //    // come from a `hash`. `url` is just one of many possible mirrors for how to
-        //    // obtain a package matching this `hash`.
-        //    //
-        //    // Uses the [multihash](https://multiformats.io/multihash/) format.
-        //    .hash = "...",
-        //
-        //    // When this is provided, the package is found in a directory relative to the
-        //    // build root. In this case the package's hash is irrelevant and therefore not
-        //    // computed. This field and `url` are mutually exclusive.
-        //    .path = "foo",
-        //},
     },
-
-    // Specifies the set of files and directories that are included in this package.
-    // Only files and directories listed here are included in the `hash` that
-    // is computed for this package.
-    // Paths are relative to the build root. Use the empty string (`""`) to refer to
-    // the build root itself.
-    // A directory listed here means that all files within, recursively, are included.
     .paths = .{
         // This makes *all* files, recursively, included in this package. It is generally
         // better to explicitly list the files and directories instead, to insure that

src/main.zig

@@ -1,24 +1,80 @@
 const std = @import("std");
+const json = @import("json");
+
+fn concat(ally: std.mem.Allocator, u: []const u8, v: []const u8) ![]const u8 {
+    const res = try ally.alloc(u8, u.len + v.len);
+    @memcpy(res[0..u.len], u);
+    @memcpy(res[u.len .. u.len + v.len], v);
+    return res;
+}
+
+const Shape = union(enum) {
+    rect: struct { w: f32, h: f32 },
+    square: struct { s: f32 },
+    circle: struct { r: f32 },
+};
+
+fn show(shape: Shape) void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    const all = gpa.allocator();
+    const text = json.toSlice(all, shape) catch unreachable;
+    defer all.free(text);
+    std.debug.print("shape: {s}\n", .{text});
+    // switch (shape) {
+    //     Shape.rect => |r| std.debug.print("rect: {} x {}\n", .{ r.w, r.h }),
+    //     Shape.square => |s| std.debug.print("square: {}\n", .{s.s}),
+    //     Shape.circle => |c| std.debug.print("circle: {}\n", .{c.r}),
+    // }
+}
+
+const Point = struct {
+    x: i32,
+    y: i32,
+};
 
 pub fn main() !void {
-    // Prints to stderr (it's a shortcut based on `std.io.getStdErr()`)
+    var big_buf: [1 << 20]u8 = undefined; // 1 MB
-    std.debug.print("All your {s} are belong to us.\n", .{"codebase"});
+    var fixed = std.heap.FixedBufferAllocator.init(&big_buf);
+    const ally = fixed.allocator();
 
-    // stdout is for the actual output of your application, for example if you
+    var s: Shape = Shape{ .circle = .{ .r = 99 } };
-    // are implementing gzip, then only the compressed bytes should be sent to
+    show(s);
-    // stdout, not any debugging messages.
+    s = Shape{ .rect = .{ .w = 1, .h = 2 } };
-    const stdout_file = std.io.getStdOut().writer();
+    show(s);
-    var bw = std.io.bufferedWriter(stdout_file);
-    const stdout = bw.writer();
 
-    try stdout.print("Run `zig build test` to run the tests.\n", .{});
+    const val = Point{ .x = 1, .y = 2 };
+    const ser = try json.toSlice(ally, val);
+    defer ally.free(ser);
 
-    try bw.flush(); // don't forget to flush!
+    std.debug.print("{s}\n", .{ser});
+
+    const deser = try json.fromSlice(ally, Point, ser);
+    std.debug.print("{any}\n", .{deser});
+
+    var hash_map = std.StringArrayHashMap([]const u8).init(ally);
+    defer hash_map.deinit();
+
+    try hash_map.put("foo", "bar");
+    try hash_map.put("fizz", "buzz");
+    try hash_map.put("qux", "quxx");
+
+    const x = try concat(ally, hash_map.get("fizz").?, hash_map.get("foo").?);
+    defer ally.free(x);
+
+    std.debug.print("x={s}\n", .{x});
+
+    var iter = hash_map.iterator();
+    while (iter.next()) |it| {
+        std.debug.print("{s} {s}\n", .{ it.key_ptr.*, it.value_ptr.* });
+    }
 }
 
-test "simple test" {
+test concat {
-    var list = std.ArrayList(i32).init(std.testing.allocator);
+    const x = "hello";
-    defer list.deinit(); // try commenting this out and see if zig detects the memory leak!
+    const y = "world";
-    try list.append(42);
+
-    try std.testing.expectEqual(@as(i32, 42), list.pop());
+    const z = try concat(std.testing.allocator, x, y);
+    defer std.testing.allocator.free(z);
+
+    try std.testing.expectEqualStrings(z, "helloworld");
 }

src/root.zig

@@ -1,10 +0,0 @@
-const std = @import("std");
-const testing = std.testing;
-
-export fn add(a: i32, b: i32) i32 {
-    return a + b;
-}
-
-test "basic add functionality" {
-    try testing.expect(add(3, 7) == 10);
-}