Updated README.md

Author: ProgMiner

Diff for: README.md

@@ -7,9 +7,7 @@
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-PHP-DataGen is a code generation tool with a built-in parser of own Kotlin-like properties description language to create classes with strongly typed properties.
-
-The base description of the language is in [schema.md](schema.md).
+The PHP-DataGen project is a utility - code generator of PHP classes with certain properties and is aimed at simplifying the work of PHP programmers.
 
 ## Install
 
@@ -21,9 +19,55 @@ $ composer require progminer/php-datagen
 
 ## Usage
 
-You can use it from your PHP code or using the CLI.
+The tool has both the ability to control the generation using PHP scripts and the CLI to work with the built-in parser of its own language (hereinafter - PDGL).
+
+### CLI
+
+```bash
+# General form
+./php-datagen <command>
+
+# File compiling
+./php-datagen compile <files>...
+
+# Project building (all files compiling)
+./php-datagen build [<project dir>]
+```
+
+### PDGL
+
+All language-supported statements are provided in the file [schema.md](schema.md) at the root of the project, but without a description of what a particular operator does. The `namespace` and `use` statements works the same as in normal PHP, but the class, fields, and their modifiers are not so simple.
+
+Of the modifiers of the class can be identified only one non-standard for PHP the `final` modifier which also has the `final!` variation. The fact is that the result of the work of PHP-DataGen - class, which must be extended by another class to work.
+
+The `final` modifier turns the class into a ready-to-use class by removing the prefix (the default, so far, without the possibility of modification, `Data_`) and the `abstract` modifier of the resulting PHP class. The `final!` modifier which "under the hood" is referred to as "final final" is an addition to the `final` modifier (and can not be used without it) and adds to the resulting PHP class the `final` modifier.
+
+#### Class field
+
+The syntax of class field very little resemblance to the syntax of PHP classes properties and even more, in my opinion, resembles the syntax of class properties Kotlin.
+
+Let's start with what is written in the file [schema.md](schema.md):
+```
+// Field declaration
+[direct] <val/var> <Field name>[: <Type name>[, <Validator names>]][ <:/</>= [`[``]]<Default value>[`[``]]];
+```
+
+And now in order (operators are bold, substitutions are italic):
+
+  - **direct** - modifier. If exists, allows the extending class to access properties directly (sets the `protected` access modifier instead of `private`);
+  - **val** or **var** is a field declaration operator. If **val** is used, the property is not editable after setting in the constructor, if **var** is editable;
+  - *Field name* - the name of the field, specified without the PHP-specific dollar sign (`$`);
+  - **:** - optional colon operator to specify the field type. If not specified, the field type is considered `mixed`;
+  - *Type name* - type name. It can be one of the standard PHP types (case-insensitive) or a class name. If it ends with a question sign (for example, `string?`) then the field as well can store `null` value;
+  - **,** - optional comma operator allows you to specify the validator name after the type (or validator) name;
+  - *Validator name* - name of validator (see next section);
+  - **<=**, **:=** or **=** - default value assignment operator. In variation **<=** assigns a value when declaring a property. In variation **:=** assigns a value when the constructor is called without checking the type and calling validators. In variation **=** assigns a value when calling a constructor with type checking and calling validators;
+  - **`** or **```** - see *Default value*;
+  - *Default value* - the default value of the field. It can be surrounded by **`** or **```** operators when contains a semicolon (`;`) (except when a variation of the default value assignment operator **<=** is used). There is no difference in the use of **`** or **```** if the default value is not contains a reverse apostrophe (```), in which case you must use the **```** operator.
+
+### Validators
 
-// TODO
+*Coming soon...*
 
 ## Contributing