Compiler Design for Stack Operations

This project implements the first three phases of a compiler—Lexical Analysis, Syntax Analysis, and Semantic Analysis—to simulate and validate stack operations such as PUSH, POP, and DISPLAY. The project is built using Flex (Lexical Analyzer) and Bison (Parser Generator), simulating how compilers process and verify source code input.

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🧠 Project Objective

To design a basic compiler that can:

• Tokenize input stack commands (Lexical Analysis)
• Parse valid command sequences (Syntax Analysis)
• Simulate correct stack behavior (Semantic Analysis)

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🛠️ Tech Stack

• Languages: C
• Tools: Flex (Lex), Bison (Yacc)
• Concepts Used:
  • Compiler Front-End
  • Context-Free Grammars (CFG)
  • Syntax-Directed Translation
  • Stack Simulation

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🚀 Features

• Lexical Analyzer: Recognizes tokens like PUSH, POP, DISPLAY, and integers.
• Parser: Validates syntax using defined grammar rules for stack operations.
• Semantic Analyzer:
  • Implements a simulated stack.
  • Enforces valid stack behavior.
  • Reports semantic errors like popping from an empty stack.
• Output: Displays operation results or error messages based on input correctness.

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📂 File Structure

├── lex.l # Lexical analyzer (Flex)
├── parser.y # Syntax and semantic analyzer (Bison)
├── input.txt # input file

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🧑‍💻 How to Run

1. Install Flex and Bison:

2. Compile the program

flex lex.l
bison -d parser.y
gcc parser.tab.c lex.yy.c -o stack_simulator

3. Run the executable

./stack_simulator

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📝 Notes

1. The implementation is educational and simulates how real-world compilers operate in the front-end.
2. Good for understanding compiler theory concepts and applying them to practical problems like stack simulations.

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📌 Future Enhancements

1. Add Intermediate Code Generation
2. Build a GUI to visualize the stack behavior
3. Extend support to more complex data structures (queues, trees)