Hat Trick Labs

Command Line

Build expressive, structured CLI applications.

 1var cmdDef = new CommandDefinition(name: "base64");
 2cmdDef.Help = "Encodes or decodes string input as base 64.";
 3cmdDef.AddOption<string>(
 4    key: "value",
 5    help: "The value to base 64 encode or decode",
 6    (terse: "-v", verbose: "--value")
 7);
 8cmdDef.AddOption<bool>(
 9    key: "encode",
10    defaultArg: true,
11    help: "True to encode...False to decode.",
12    (terse: "-e", verbose: "--encode")
13);
14cmdDef.Handler = (cmd) =>
15{
16    bool encode = cmd["encode"].GetValue<bool>();
17    string input = cmd["value"].GetValue<string>();
18    Console.WriteLine(encode ? Base64.Encode(input) : Base64.Decode(input));
19};
20DefinitionRegistry.GetInstance().Add(cmdDef);

Built-in validation

Option- and command-level constraints run before your handler.

Self-documenting help

Rendered directly from your command, option, and constraint definitions. No extra content to write.

MemDb

Fast, lightweight in-memory database with file-backed durability.

 1var db = MemDb.Open<Asset>("assets");
 2var count = db.Count(a => a.Extension == ".jpg" && a.Tags.Contains("pets"));
 3
 4//get page 1 of (count / 100) total pages of pets pics in .jpg format
 5Asset[] pets = db.Query()
 6    .Where(a => a.Extension == ".jpg" && a.Tags.Contains("pets"))
 7    .OrderBy((a, b) => a.CreatedAt.CompareTo(b.CreatedAt))
 8    .Skip(0)
 9    .Limit(100)
10    .ToArray();
11
12//update page, apply last access timestamp
13db.Update(
14    apply: (a) => a.LastAccessAt = DateTime.UtcNow,
15    where: (a) => Array.Exists(pets, (p) => p.Id == a.Id)
16);
17db.Dispose();

Safe by default

Thread-safe in-process. Records deep-cloned at the cache boundary — no reference aliasing.

Native C# queries

Fluent builder for filtering, sorting, and bulk writes. No SQL.

Text Templates

Flexible text templating engine with a small, fixed grammar.

<html>
<head>
<title>{Title}</title>
</head>
<body>
    <h1>Hello {($)=>GetFullName},</h1>
<div>
Thank you for registering for the following {($) => GetSvcCount} services:
</div>
<ul>
{#each Services}
    <li>{Name}</li>
{/each}
</ul>

{#if IsGoldMember}
<div>You will receive a 5% discount.</div>
{/if}

<div>Thank you,</div>
<div>{Supervisor}</div>
</body>
</html>

No precompile step

Single-pass interpreter. No cold-start cost in serverless functions and other stateless workloads.

Lambda extensions

Host-registered functions invokable from any tag.

Configuration

Typed JSON config and environment variables, explicit and validated at startup.

 1var configMgr = JsonConfigManager.BuildInstance("default")
 2    .Register<AppSettings>("app-settings.json")
 3    .ApplyValidatorFor<AppSettings>(
 4        c => c.TimeoutSeconds > 0,
 5        "TimeoutSeconds must be positive"
 6    )
 7    .Build();
 8
 9AppSettings settings = configMgr.Get<AppSettings>();
10Console.WriteLine(settings.ApiBaseUrl);
11
12//adjust a runtime setting; rejected if the file changed since last read
13settings.TimeoutSeconds = 15;
14bool applied = configMgr.Put(settings);

Authenticated encryption

Optional AES-256-GCM encryption for JSON files and environment variable values.

Explicit by design

One source per registration. No provider chain, no DI container required.

The tools we use, shared openly.