Initial

.gitignore

@@ -1,2 +1,39 @@
-yarn.lock
-package-lock.json
+### Maven template
+target/
+
+### OSX template
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+### Java template
+*.class
+
+### JetBrains template
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm
+*.iml
+
+## Directory-based project format:
+.idea/
+
+## File-based project format:
+*.ipr
+*.iws

.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,19 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+wrapperVersion=3.3.2
+distributionType=only-script
+distributionUrl=http://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.9.4/apache-maven-3.9.4-bin.zip

.tool-versions

@@ -0,0 +1 @@
+java temurin-11.0.22+7

README.md

@@ -1,229 +1,99 @@
-<div id="top"></div>
-
-<!-- NOTES -->
-<!--
-*** Individual sections below can be removed if not needed
--->
-
-<!-- PROJECT SHIELDS -->
-<!--
-*** We are using markdown "reference style" links for readability.
-*** Reference links are enclosed in brackets [ ] instead of parentheses ( ).
-*** See the bottom of this document for the declaration of the reference variables
-*** for contributors-url, forks-url, etc. This is an optional, concise syntax you may use.
-*** https://www.markdownguide.org/basic-syntax/#reference-style-links
--->
-[![Contributors][contributors-shield]][contributors-url]
-[![Forks][forks-shield]][forks-url]
-[![Stargazers][stars-shield]][stars-url]
-[![Issues][issues-shield]][issues-url]
-[![MIT License][license-shield]][license-url]
-[![LinkedIn][linkedin-shield]][linkedin-url]
-
-
-
-<!-- PROJECT LOGO -->
-<br />
-<div align="center">
-  <a href="https://github.com/github_username/repo_name">
-    <img src="images/logo.png" alt="Logo" width="80" height="80">
-  </a>
-
-<h3 align="center">project_title</h3>
-
-  <p align="center">
-    project_description
-    <br />
-    <a href="https://github.com/github_username/repo_name"><strong>Explore the docs »</strong></a>
-    <br />
-    <br />
-    <a href="https://github.com/github_username/repo_name">View Demo</a>
-    ·
-    <a href="https://github.com/github_username/repo_name/issues">Report Bug</a>
-    ·
-    <a href="https://github.com/github_username/repo_name/issues">Request Feature</a>
-  </p>
-</div>
-
-
-
-<!-- TABLE OF CONTENTS -->
-<details>
-  <summary>Table of Contents</summary>
-  <ol>
-    <li>
-      <a href="#about-the-project">About The Project</a>
-      <ul>
-        <li><a href="#built-with">Built With</a></li>
-      </ul>
-    </li>
-    <li>
-      <a href="#getting-started">Getting Started</a>
-      <ul>
-        <li><a href="#prerequisites">Prerequisites</a></li>
-        <li><a href="#installation">Installation</a></li>
-      </ul>
-    </li>
-    <li><a href="#usage">Usage</a></li>
-    <li><a href="#roadmap">Roadmap</a></li>
-    <li><a href="#contributing">Contributing</a></li>
-    <li><a href="#license">License</a></li>
-    <li><a href="#contact">Contact</a></li>
-    <li><a href="#acknowledgments">Acknowledgments</a></li>
-  </ol>
-</details>
-
-
-
-<!-- ABOUT THE PROJECT -->
-## About The Project
-
-[![Product Name Screen Shot][product-screenshot]](https://example.com)
-
-Here's a blank template to get started: To avoid retyping too much info. Do a search and replace with your text editor for the following: `github_username`, `repo_name`, `twitter_handle`, `linkedin_username`, `email`, `email_client`, `project_title`, `project_description`
-
-<p align="right">(<a href="#top">back to top</a>)</p>
-
-
-
-### Built With
-
-* [Next.js](https://nextjs.org/)
-* [React.js](https://reactjs.org/)
-* [Vue.js](https://vuejs.org/)
-* [Angular](https://angular.io/)
-* [Svelte](https://svelte.dev/)
-* [Laravel](https://laravel.com)
-* [Bootstrap](https://getbootstrap.com)
-* [JQuery](https://jquery.com)
-
-<p align="right">(<a href="#top">back to top</a>)</p>
-
-
-
-<!-- GETTING STARTED -->
-## Getting Started
-
-This is an example of how you may give instructions on setting up your project locally.
-To get a local copy up and running follow these simple example steps.
-
-### Prerequisites
-
-This is an example of how to list things you need to use the software and how to install them.
-* npm
-  ```sh
-  npm install npm@latest -g
-  ```
-
-### Installation
-
-1. Get a free API Key at [https://example.com](https://example.com)
-2. Clone the repo
-   ```sh
-   git clone https://github.com/github_username/repo_name.git
-   ```
-3. Install NPM packages
-   ```sh
-   npm install
-   ```
-4. Enter your API in `config.js`
-   ```js
-   const API_KEY = 'ENTER YOUR API';
-   ```
-
-<p align="right">(<a href="#top">back to top</a>)</p>
-
-
-
-<!-- USAGE EXAMPLES -->
-## Usage
-
-Use this space to show useful examples of how a project can be used. Additional screenshots, code examples and demos work well in this space. You may also link to more resources.
-
-_For more examples, please refer to the [Documentation](https://example.com)_
-
-<p align="right">(<a href="#top">back to top</a>)</p>
-
-
-
-<!-- ROADMAP -->
-## Roadmap
-
-- [] Feature 1
-- [] Feature 2
-- [] Feature 3
-    - [] Nested Feature
-
-See the [open issues](https://github.com/github_username/repo_name/issues) for a full list of proposed features (and known issues).
-
-<p align="right">(<a href="#top">back to top</a>)</p>
-
-
-
-<!-- CONTRIBUTING -->
-## Contributing
-
-Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are **greatly appreciated**.
-
-If you have a suggestion that would make this better, please fork the repo and create a pull request. You can also simply open an issue with the tag "enhancement".
-Don't forget to give the project a star! Thanks again!
-
-1. Fork the Project
-2. Create your Feature Branch (`git checkout -b feature/AmazingFeature`)
-3. Commit your Changes (`git commit -m 'Add some AmazingFeature'`)
-4. Push to the Branch (`git push origin feature/AmazingFeature`)
-5. Open a Pull Request
-
-<p align="right">(<a href="#top">back to top</a>)</p>
-
-
-
-<!-- LICENSE -->
-## License
-
-Distributed under the Apache 2.0 License. See `LICENSE.txt` for more information.
-
-<p align="right">(<a href="#top">back to top</a>)</p>
-
-
-
-<!-- MAINTAINERS -->
-## Maintainers
-
-- Full Name 1
-  - GitHub Enterprise: [github_username](https://github.com/username1)
-  - Email: [email protected]
-- Full Name 2
-  - GitHub Enterprise: [github_username](https://github.com/username2)
-  - Email: [email protected]
-
-<p align="right">(<a href="#top">back to top</a>)</p>
-
-
-
-<!-- ACKNOWLEDGMENTS -->
-## Acknowledgments
-
-* []()
-* []()
-* []()
-
-<p align="right">(<a href="#top">back to top</a>)</p>
-
-
-
-<!-- MARKDOWN LINKS & IMAGES -->
-<!-- https://www.markdownguide.org/basic-syntax/#reference-style-links -->
-[contributors-shield]: https://img.shields.io/github/contributors/github_username/repo_name.svg?style=for-the-badge
-[contributors-url]: https://github.com/github_username/repo_name/graphs/contributors
-[forks-shield]: https://img.shields.io/github/forks/github_username/repo_name.svg?style=for-the-badge
-[forks-url]: https://github.com/github_username/repo_name/network/members
-[stars-shield]: https://img.shields.io/github/stars/github_username/repo_name.svg?style=for-the-badge
-[stars-url]: https://github.com/github_username/repo_name/stargazers
-[issues-shield]: https://img.shields.io/github/issues/github_username/repo_name.svg?style=for-the-badge
-[issues-url]: https://github.com/github_username/repo_name/issues
-[license-shield]: https://img.shields.io/github/license/github_username/repo_name.svg?style=for-the-badge
-[license-url]: https://github.com/github_username/repo_name/blob/master/LICENSE.txt
-[linkedin-shield]: https://img.shields.io/badge/-LinkedIn-black.svg?style=for-the-badge&logo=linkedin&colorB=555
-[linkedin-url]: https://linkedin.com/in/linkedin_username
-[product-screenshot]: images/screenshot.png
+# templ
+
+## Easy Handling of Delimiters that Accompany Optional Data
+
+This library provides a simple solution to a common use case in configuration variables:
+> _A delimiter is needed to accompany optional data, but must not be present when the optional data is missing._
+
+Traditionally this scenario is solved in one of two ways:
+* Treat the delimiter as required, forcing a default value to always be defined and available.
+* Embed the optional delimiter in the actual value of the optional data, essentially _corrupting_ the value of the data (`PORT="80"` becomes `PORT=":80"` but clearly the value `:80` is not a valid port number.)
+
+## templ - Is a Primitive Library
+Don't expect to use `templ` without writing a little code around it: it is primitive.  This library Does One Thing: the substitution processing.  You'll need to provide the bindings into your context and use case.
+
+## templ - Solution
+The solution pattern provided by `templ` is to include the delimiter(s) inside the double-braces template substitution syntax `{{}}` (as a prefix and/or a suffix).
+
+### Case 1: Undefined value - delimiter is omitted
+```
+API_HOST="api.example.com"
+API_ENDPOINT="{{API_HOST}}{{:API_PORT}}"
+```
+#### Result: `api.example.com`
+(With `API_PORT` undefined, the `:` is excluded from the result.)
+
+### Case 2: Defined value - delimiter is included
+```
+API_HOST="api.example.com"
+API_PORT="8080"
+API_ENDPOINT="{{API_HOST}}{{:API_PORT}}"
+```
+#### Result: `api.example.com:8080`
+(With `API_PORT` defined, the `:` is included in the result.)
+
+## Supported Delimiters
+There are eighteen supported delimiters:
+
+1. ` <space> `
+2. ` , `
+3. ` . `
+4. ` ; `
+5. ` : `
+6. ` ? `
+7. ` & `
+8. ` @ `
+9. ` # `
+10. ` / `
+11. ` ( `
+12. ` ) `
+13. ` < `
+14. ` > `
+15. ` _ `
+16. ` - `
+17. ` \ `
+18. ` | `
+
+### Delimiter Rules
+* Delimiters can be used as a prefix and/or suffix.
+* Any number of delimiters can be used in any combination.
+
+## Nested Evaluation (Dynamic Variables)
+Variables can be dynamic.
+
+### Example 1:
+```
+INSTANCE="3"
+HOST_1="devhost1.example.com"
+HOST_2="devhost2.example.com"
+HOST_3="qa.example.com"
+HOST_4="example.com"
+SERVICE_ENDPOINT="{{HOST_{{INSTANCE}}}}"
+```
+
+This usefulness is compounded when multiple variables are resolved:
+
+### Example 1:
+```
+INSTANCE="3"
+HOST_1="devhost.example.com"
+PORT_1="8080"
+HOST_2="devhost.example.com"
+PORT_2="8081"
+HOST_3="qa.example.com"
+HOST_4="example.com"
+SERVICE_ENDPOINT="{{HOST_{{INSTANCE}}}}{{:PORT_{{INSTANCE}}}}"
+```
+
+## UPPERCASE
+The value returned by a template evaluation can be converted to uppercase using the `^` character before the variable name.
+
+### Example:
+```
+ENV="dev"
+HOST_DEV="vm123.example.com"
+HOST_QA="qa.example.com"
+HOST_PROD="example.com"
+SERVICE_ENDPOINT="{{HOST_{{^ENV}}}}"
+```
+> This example shows both the `^` UPPERCASE syntax, and the nested-template resolution to resolve values dynamically.