docs(readme): Update README.md

README.md

@@ -4,6 +4,79 @@ A NFA based regular expression engine implemented in Motoko.
 
 ⚠️ **Note**: This project is currently under development and not intended for production use.
 
+## Architecture
+
+The following diagram illustrates the core components and data flow of the regex engine:
+
+```mermaid
+graph TD
+    subgraph Input
+        input[TEXT INPUT]
+        cursor[EXTERNAL CURSOR]
+    end
+
+    subgraph Engine Core
+        lexer[LEXER]
+        parser[PARSER]
+        compiler[COMPILER]
+        matcher[MATCHER]
+        api[REGEX API]
+    end
+
+    subgraph Outputs
+        tokens[Tokens]
+        ast[AST]
+        nfa[NFA]
+        result[MATCH RESULT]
+    end
+
+    %% Input flow
+    input --> cursor
+    cursor --> lexer
+
+    %% Main processing flow
+    lexer --> tokens
+    tokens --> parser
+    parser --> ast
+    ast --> compiler
+    compiler --> nfa
+    nfa --> matcher
+    matcher --> result
+
+    %% API connections
+    api --> lexer
+    api --> parser
+    api --> compiler
+    api --> matcher
+
+    %% Styling
+    classDef core fill:#f5f5f5,stroke:#333,stroke-width:2px
+    classDef output fill:#e1f5fe,stroke:#333
+    classDef api fill:#fff3e0,stroke:#333,stroke-width:2px
+
+    class lexer,parser,compiler,matcher core
+    class tokens,ast,nfa,result output
+    class api api
+```
+
+### Component Description
+
+1. **Input Processing**:
+   - Text Input: Raw regular expression string
+   - External Cursor: Character-by-character stream processor
+
+2. **Core Components**:
+   - **Lexer**: Tokenizes the input stream into meaningful regex components
+   - **Parser**: Builds an Abstract Syntax Tree (AST) from tokens
+   - **Compiler**: Transforms the AST into a Non-deterministic Finite Automaton (NFA)
+   - **Matcher**: Executes pattern matching using the compiled NFA
+
+3. **Intermediate Outputs**:
+   - Tokens: Lexical units of the regex pattern
+   - AST: Tree representation of the pattern structure
+   - NFA: State machine for pattern matching
+   - Match Result: Final output indicating match success/failure and captures
+
 ## Installation
 
 You can install the regex engine using [MOPS](https://mops.one/):