Added a new chapter Validation Rules

- Introduces a standardized mini-language for declarative configuration validation.
- Covers document structure, node rules, types, constraints, templates, dependencies, versioning, diagnostics, and security considerations.
- Enables portable, implementation-independent validation of ELCL configuration documents.

Author: erbsland-dev

.github/FUNDING.yml

@@ -1,6 +1,7 @@
 /.venv/
 /venv/
 /.idea/
+/build
 /build/**
 __pycache__
 .DS_Store

.gitignore

@@ -4,11 +4,12 @@ The Erbsland Configuration Language (*ELCL*) is a human-centric configuration fo
 
 ## Current Status
 
-**ELCL version 1.0 has been officially released.** The language specification is complete, and reference implementations are currently in development and will be available soon.
+**ELCL version 1.2 has been officially released.** The language specification is complete, and reference implementations for c++ and python are available:
+- [C++ Reference Implementation](https://github.com/erbsland-dev/erbsland-cpp-configuration)
+- [Python Reference Implementation](https://github.com/erbsland-dev/erbsland-py-conf).
 
 What’s still pending:
-- There are currently no defined guidelines for verification rules or for implementing a parser API. These sections will be published once the reference implementations are finalized.
-- Also, there are currently no contribution guidelines for the language specification. 
+- There are no contribution guidelines for the language specification. 
 
 ## Where to Start?
 
@@ -27,10 +28,11 @@ What’s still pending:
 * **Compliance Test Suite**: An extensive test suite ensures that parsers conform to the *ELCL* specification, fostering reliable and consistent implementations.
 * **Implementation Levels**: *ELCL* supports various implementation levels, from lightweight micro-parsers for resource-constrained environments to full-featured parsers that handle complex configurations seamlessly.
 * **Metadata Support**: Metadata statements allow you to specify language versions and required features, ensuring backward compatibility and future-proofing.
+* **Validation Rules**: A standardized mini-language for validating configuration documents, ensuring data integrity and adherence to application-specific constraints.
 
 ## License
 
-Copyright (c) 2025 Tobias Erbsland - Erbsland DEV. https://erbsland.dev
+Copyright (c) 2025-2026 Tobias Erbsland - Erbsland DEV. https://erbsland.dev
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

README.md

@@ -10,20 +10,30 @@
 Changelog
 *********
 
-Version 1.0.10 - 2025-09-01
+Version 1.2.0 — 2026-01-22
+==========================
+
+*   Added a new chapter :doc:`validation-rules/index` defining **ELCL Validation Rules (ELCL-VR)**:
+
+    *   Introduces a standardized mini-language for declarative configuration validation.
+    *   Covers document structure, node rules, types, constraints, templates, dependencies,
+        versioning, diagnostics, and security considerations.
+    *   Enables portable, implementation-independent validation of ELCL configuration documents.
+
+Version 1.0.10 — 2025-09-01
 ===========================
 
 * Added a page with a list of all known parser implementations.
 * Explained how to add your own parser to the list.
 * Improved the contribution guide with buttons to create issues and start discussions.
 
-Version 1.0.8 - 2025-08-22
+Version 1.0.8 — 2025-08-22
 ==========================
 
 * Added the colon to the list of escaped characters in the "Test Outcome Format" chapter. This character had been accidentally omitted.
 * Added a design rationale box to explain the reasoning behind the escaping rules.
 
-Version 1.0.6 - 2025-08-14
+Version 1.0.6 — 2025-08-14
 ==========================
 
 * Added examples of invalid floating-point values for clarity.
@@ -32,15 +42,15 @@ Version 1.0.6 - 2025-08-14
 * Broadened the rule to better deny any non-decimal formats for floating-point values.
 * Refined explanation of behavior when limits are exceeded, removing potentially misleading rounding example in the context of floating-point numbers.
 
-Version 1.0.4 - 2025-07-10
+Version 1.0.4 — 2025-07-10
 ==========================
 
 - Clarified the relationship between `Syntax` and its specialized subcategories (`Character`, `UnexpectedEnd`, `Indentation`, `LimitExceeded`, `Unsupported`).
 - Reworded and expanded descriptions to improve readability and precision for parser implementors.
 - Added design rationales to explain the purpose and intent behind each specialized category.
 - Explicitly stated that distinguishing specialized errors is optional for parser conformance.
 
-Version 1.0.0 - 2025-07-09
+Version 1.0.0 — 2025-07-09
 ==========================
 
 - Initial release

data/constraint-matrix.json

@@ -7,17 +7,27 @@
 
 sys.path.insert(0, str(Path(__file__).parent))
 
+# -- Project information -----------------------------------------------------
 project = "Erbsland Configuration Language"
 copyright = "2025, Erbsland DEV"
 author = "Erbsland DEV"
 release = "1.0"
-extensions = ["sphinx_rtd_theme", "_ext.styles", "sphinx_design"]
+
+# -- General configuration ---------------------------------------------------
+extensions = ["sphinx_rtd_theme", "sphinx_design", "sphinx_copybutton", "_ext.styles"]
 templates_path = ["_templates"]
 exclude_patterns = ["build", "_build", "Thumbs.db", ".DS_Store"]
+
+# -- Options for HTML output -------------------------------------------------
 html_theme = "sphinx_rtd_theme"
 html_static_path = ["_static"]
-html_css_files = ["custom.css"]
-html_js_files = ["overlay.js"]
+html_css_files = [
+    "custom.css",
+]
+html_js_files = [
+    "overlay.js",
+    "https://erbsland.dev/ext/fa7/js/all.min.js",
+]
 
 
 def setup(app):

doc/_static/custom.css

@@ -0,0 +1,37 @@
+
+:root {
+    --color-design-rationale-bg: rgb(243, 231, 250);
+    --color-design-rationale-title-bg: rgb(152, 106, 222);
+    --color-design-rationale-title-text: white;
+    --color-micro-parser-specs-bg: #fff;
+    --color-micro-parser-specs-title-bg: #e8e8e8;
+    --color-micro-parser-specs-title-text: #444;
+}
+
+.design-rationale.admonition {
+    background-color: var(--color-design-rationale-bg);
+
+    .admonition-title {
+        background-color: var(--color-design-rationale-title-bg);
+        color: var(--color-design-rationale-title-text);
+    }
+
+    .admonition-title::before {
+        content: "\f040";
+    }
+}
+
+.micro-parser-specs.admonition {
+    background-color: var(--color-micro-parser-specs-bg);
+    border: 1px solid var(--color-micro-parser-specs-title-bg);
+
+    .admonition-title {
+        color: var(--color-micro-parser-specs-title-text);
+        background-color: var(--color-micro-parser-specs-title-bg);
+    }
+
+    .admonition-title::before {
+        content: "\f2db";
+    }
+}
+

doc/changelog.rst

@@ -0,0 +1,19 @@
+
+.banner {
+    width: 100%;
+    background-color: #cd5a13;
+    color: white;
+    padding: 0.5em 3em;
+    margin: 0 0 0 10em;
+    font-size: 16px;
+    font-weight: 400;
+    text-align: center;
+    border-bottom: 5px solid #e4d3aa;
+}
+
+@media screen and (max-width: 768px) {
+    .banner {
+        margin: 0;
+    }
+}
+

doc/conf.py

@@ -0,0 +1,9 @@
+
+:root {
+    --color-bnf-border: #3488db;
+}
+
+.rst-content div.highlight-bnf {
+    border: 1px solid var(--color-bnf-border);
+}
+