Implement json stringification and parsing

.gitignore

@@ -1 +1,22 @@
-/zig-cache/
+# This file is for zig-specific build artifacts.
+# If you have OS-specific or editor-specific files to ignore,
+# such as *.swp or .DS_Store, put those in your global
+# ~/.gitignore and put this in your ~/.gitconfig:
+#
+# [core]
+#     excludesfile = ~/.gitignore
+#
+# Cheers!
+# -andrewrk
+
+.zig-cache/
+zig-out/
+/release/
+/debug/
+/build/
+/build-*/
+/docgen_tmp/
+
+# Although this was renamed to .zig-cache, let's leave it here for a few
+# releases to make it less annoying to work with multiple branches.
+zig-cache/

uuid.zig

@@ -4,6 +4,8 @@
 const std = @import("std");
 const crypto = std.crypto;
 const fmt = std.fmt;
+const json = std.json;
+const Allocator = std.mem.Allocator;
 const testing = std.testing;
 
 pub const Error = error{InvalidUUID};
@@ -22,9 +24,9 @@ pub const UUID = struct {
         return uuid;
     }
 
-    fn to_string(self: UUID,slice: []u8) void {
-        var string:[36]u8 = format_uuid(self);
-        std.mem.copy(u8, slice, &string);
+    fn to_string(self: UUID, slice: []u8) void {
+        var string: [36]u8 = format_uuid(self);
+        std.mem.copyForwards(u8, slice, &string);
     }
 
     fn format_uuid(self: UUID) [36]u8 {
@@ -114,6 +116,23 @@ pub const UUID = struct {
 
         return uuid;
     }
+
+    pub fn jsonStringify(self: UUID, out: anytype) !void {
+        return out.print("\"{s}\"", .{self.format_uuid()});
+    }
+
+    pub fn jsonParse(
+        allocator: Allocator,
+        source: anytype,
+        _: json.ParseOptions,
+    ) !UUID {
+        switch (try source.nextAlloc(allocator, .alloc_if_needed)) {
+            .string, .allocated_string => |value| {
+                return parse(value) catch error.InvalidCharacter;
+            },
+            else => return error.UnexpectedToken,
+        }
+    }
 };
 
 // Zero UUID
@@ -166,3 +185,43 @@ test "check to_string works" {
     std.debug.print("Second call to_string {s} \n", .{string2});
     try testing.expectEqual(string1, string2);
 }
+
+test "jsonStringify" {
+    const uuid = UUID{
+        .bytes = [_]u8{ 0x12, 0x34, 0x56, 0x78, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+    };
+    const T = struct { id: UUID };
+    const res = try json.stringifyAlloc(testing.allocator, T{
+        .id = uuid,
+    }, .{});
+    defer testing.allocator.free(res);
+    try testing.expectEqualStrings("{\"id\":\"12345678-0000-0000-0000-000000000000\"}", res);
+
+    const res2 = try json.stringifyAlloc(testing.allocator, uuid, .{});
+    defer testing.allocator.free(res2);
+    try testing.expectEqualStrings("\"12345678-0000-0000-0000-000000000000\"", res2);
+}
+
+test "jsonParse" {
+    const T = struct { id: UUID };
+
+    const res = try json.parseFromSlice(
+        T,
+        testing.allocator,
+        "{\"id\": \"12345678-0000-0000-0000-000000000000\"}",
+        .{},
+    );
+    defer res.deinit();
+    try testing.expectEqual([_]u8{ 0x12, 0x34, 0x56, 0x78, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, res.value.id.bytes);
+}
+
+test "bad jsonParse" {
+    const T = struct { id: UUID };
+
+    try testing.expectError(error.UnexpectedToken, json.parseFromSlice(
+        T,
+        testing.allocator,
+        "{\"id\": 123123}",
+        .{},
+    ));
+}