update documentation about polyfills (new feature upcoming with relea…

…se 6.4, see #237)

docs/01_Components/05_Polyfills/Features.md

@@ -0,0 +1,93 @@
+<!-- markdownlint-disable MD013 -->
+# Polyfills
+
+Before version 6.4, PHP CompatInfo and its compatibility analyser was not able to detect packages 
+that provides compatibility layers for some extensions and functions.
+
+Since version 6.4, PHP CompatInfo used a polyfill architecture to detect such packages 
+that backports features found in the latest PHP versions.
+
+Each polyfill package must be supported both with [PHP CompatInfoDB](https://github.com/llaville/php-compatinfo-db) (since release 4.2.0) 
+to identify PHP features (classes, constants, functions), and CompatInfo itself by services implementing the `Bartlett\CompatInfo\Application\Polyfills\PolyfillInterface`
+
+Here is the list of available polyfill services supported (namespace `Bartlett\CompatInfo\Application\Polyfills`) :
+
+## [Ctype extension](https://github.com/symfony/polyfill-ctype)
+
+| Polyfill class name | Description |
+|---|---|
+| `SymfonyCtype` | This polyfill detects PHP native `ctype_*` functions to users who run php versions without the ctype extension |
+
+Available since release 6.4.0
+
+## [Iconv extension](https://github.com/symfony/polyfill-iconv)
+
+| Polyfill class name | Description |
+|---|---|
+| `SymfonyIconv` | This polyfill detects PHP native `iconv_*` functions to users who run php versions without the iconv extension |
+
+Available since release 6.4.0
+
+## [Mbstring extension](https://github.com/symfony/polyfill-mbstring)
+
+| Polyfill class name | Description |
+|---|---|
+| `SymfonyMbstring` | This polyfill detects PHP native `mb_*` functions to users who run php versions without the mbstring extension |
+
+Available since release 6.4.0
+
+## [PHP 7.0](https://github.com/symfony/polyfill-php70)
+
+| Polyfill class name | Description |
+|---|---|
+| `SymfonyPhp70` | This polyfill detects features unavailable in releases prior to PHP 7.0 |
+
+Available since release 6.4.0
+
+## [PHP 7.1](https://github.com/symfony/polyfill-php71)
+
+| Polyfill class name | Description |
+|---|---|
+| `SymfonyPhp71` | This polyfill detects features unavailable in releases prior to PHP 7.1 |
+
+Available since release 6.4.0
+
+## [PHP 7.2](https://github.com/symfony/polyfill-php72)
+
+| Polyfill class name | Description |
+|---|---|
+| `SymfonyPhp72` | This polyfill detects features unavailable in releases prior to PHP 7.2 |
+
+Available since release 6.4.0
+
+## [PHP 7.3](https://github.com/symfony/polyfill-php73)
+
+| Polyfill class name | Description |
+|---|---|
+| `SymfonyPhp73` | This polyfill detects features unavailable in releases prior to PHP 7.3 |
+
+Available since release 6.4.0
+
+## [PHP 7.4](https://github.com/symfony/polyfill-php74)
+
+| Polyfill class name | Description |
+|---|---|
+| `SymfonyPhp74` | This polyfill detects features unavailable in releases prior to PHP 7.4 |
+
+Available since release 6.4.0
+
+## [PHP 8.0](https://github.com/symfony/polyfill-php80)
+
+| Polyfill class name | Description |
+|---|---|
+| `SymfonyPhp80` | This polyfill detects features unavailable in releases prior to PHP 8.0 |
+
+Available since release 6.4.0
+
+## [PHP 8.1](https://github.com/symfony/polyfill-php81)
+
+| Polyfill class name | Description |
+|---|---|
+| `SymfonyPhp81` | This polyfill detects features unavailable in releases prior to PHP 8.1 |
+
+Available since release 6.4.0

docs/README.md

@@ -72,6 +72,10 @@ PHPCompatInfo can be extended by registering objects that implement one or more
 
 Furthermore, extensions may implement the `Symfony\Component\EventDispatcher\EventSubscriberInterface` in order to have its event handlers automatically registered with the EventDispatcher when the extension is loaded.
 
+### [Polyfills](01_Components/05_Polyfills/Features.md)
+
+They are identified by services that implements the `Bartlett\CompatInfo\Application\Polyfills\PolyfillInterface`.
+
 ## [Configuration(s)](02_Configs/README.md)
 
 Load a config for CLI Application with the `--config` option.