feat: add cogna-dev/x/mustache package with official spec-based coverage

README.md

@@ -4,7 +4,7 @@
 [![Publish](https://github.com/cogna-dev/x/actions/workflows/publish.yml/badge.svg)](https://github.com/cogna-dev/x/actions/workflows/publish.yml)
 [![Document](https://github.com/cogna-dev/x/actions/workflows/document.yml/badge.svg)](https://github.com/cogna-dev/x/actions/workflows/document.yml)
 [![MoonBit](https://img.shields.io/badge/MoonBit-ready-8A2BE2)](https://www.moonbitlang.com/)
-[![Version](https://img.shields.io/badge/version-v0.1.1-2ea44f)](https://github.com/cogna-dev/x/releases)
+[![Version](https://img.shields.io/badge/version-v0.1.3-2ea44f)](https://github.com/cogna-dev/x/releases)
 
 ```text
    _________  ____  _   _______    ____  _______ _    __
@@ -30,6 +30,7 @@ Experimental monorepo for real-world [MoonBit](https://www.moonbitlang.com/) pac
 |---------|-------------|
 | [`cogna-dev/x/hcl`](src/hcl/) | HCL parser built with `cogna-dev/parkit/nom` |
 | [`cogna-dev/x/logo`](src/logo/) | Prints the ASCII art for "Cogna" |
+| [`cogna-dev/x/mustache`](src/mustache/) | Mustache template renderer with spec-based tests |
 | [`cogna-dev/x/sarif`](src/sarif/) | SARIF 2.1.0 static types with JSON encode/decode |
 
 ## Development

moon.mod.json

@@ -1,6 +1,6 @@
 {
   "name": "cogna-dev/x",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "deps": {
     "cogna-dev/parkit": "0.1.1"
   },

src/mustache/README.md

@@ -0,0 +1,79 @@
+# `cogna-dev/x/mustache`
+
+[![MoonBit](https://img.shields.io/badge/MoonBit-package-6C47FF)](https://www.moonbitlang.com/)
+[![Mustache](https://img.shields.io/badge/template-Mustache-111827)](https://mustache.github.io/)
+[![Spec](https://img.shields.io/badge/tests-official%20spec-16A34A)](https://github.com/mustache/spec)
+[![Status](https://img.shields.io/badge/status-experimental-F59E0B)](../../README.md)
+
+```text
+  __  ___          __            __
+ /  |/  /_  ______/ /_____ _____/ /_  ___
+/ /|_/ / / / / __  / __/ // / _  / _ \/ _ \
+/_/  /_/\_,_/\_,_/_/\__\_,_/\_,_/\___/\___/
+```
+
+Minimal Mustache rendering for MoonBit with practical, spec-driven behavior.
+
+## Features
+
+- Escaped interpolation: `{{name}}`
+- Unescaped interpolation: `{{{name}}}`, `{{&name}}`
+- Sections and inverted sections: `{{#x}}...{{/x}}`, `{{^x}}...{{/x}}`
+- Dotted-name lookup and implicit iterator (`{{.}}`)
+- Comments (`{{! ... }}`)
+- Partials (`{{>partial}}`)
+- Delimiter switching (`{{= <% %> =}}`)
+
+## Usage
+
+### API
+
+```moonbit
+pub fn render(template : String, data : Json, partials? : Map[String, String]) -> String
+```
+
+### Basic interpolation
+
+```moonbit
+let out = @mustache.render(
+  "Hello, {{subject}}!",
+  Json::object({ "subject": Json::string("world") }),
+)
+// out == "Hello, world!"
+```
+
+### Sections and dotted names
+
+```moonbit
+let template = "{{#person}}{{name}} from {{meta.city}}{{/person}}"
+let data = Json::object({
+  "person": Json::object({
+    "name": Json::string("Joe"),
+    "meta": Json::object({ "city": Json::string("Berlin") }),
+  }),
+})
+let out = @mustache.render(template, data)
+```
+
+### Partials
+
+```moonbit
+let template = "{{>card}}"
+let data = Json::object({ "title": Json::string("Hello") })
+let partials = { "card": "[{{title}}]" }
+let out = @mustache.render(template, data, partials=partials)
+// out == "[Hello]"
+```
+
+## Specification coverage
+
+This package includes tests adapted from official Mustache spec cases:
+
+- interpolation
+- sections
+- inverted sections
+- comments
+- delimiters
+- partials
+
+Reference: <https://github.com/mustache/spec>