Compiler Project (Group 22)

A modular implementation of a compiler front-end for a custom programming language.
This project includes components for lexical analysis, parsing (LL(1)), grammar processing, and utility structures such as tries and string handling.

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Team Members

Name	ID
Archit Garg	2022B2A71602PP
Aadit Shah	2022B3A70612P
Rishant Sharma	2022B5A70814P
Rishab Chetal	2023A7PS0015P
Gaurang Gupta	2023A7PS0648P
Ansh Bansal	2023A7PS0645P

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Features

• Lexical Analyzer

• Tokenizes input source code

• Handles identifiers, keywords, numbers, operators, etc.

• Uses Trie-based keyword lookup for efficiency

• Parser (LL(1))

• Implements grammar using recursive rules

• Builds parsing structure based on FIRST and FOLLOW sets

• Detects syntax errors

• Grammar Handling

• Predefined grammar using structured rules

• FIRST and FOLLOW set computation

• Handles epsilon productions and dependencies

• Utilities

• Custom string comparison functions

• Trie implementation for keyword recognition

• Helper functions for grammar processing

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Project Structure

1. String Utilities

   • (a) string.c – Implementation of string comparison logic
   • (b) string.h – Header file with function declarations

2. Trie (Keyword Recognition)

   • (a) trie.c – Trie implementation for keyword insertion and search
   • (b) trie.h – Trie structure definitions and function prototypes

3. Grammar & Utility Functions

   • (a) utils.c – FIRST/FOLLOW computation and grammar processing
   • (b) utils.h – Function declarations for grammar utilities

4. Core Definitions

   • (a) lexerDef.h – Token definitions (used by lexer and parser)
   • (b) parserDef.h – Grammar structures and parser-related definitions

5. Test Cases

   • (a) t1.txt – Lexer testing (invalid syntax)
   • (b) t2.txt – Sum of N numbers
   • (c) t3.txt – Record handling and averaging
   • (d) t4.txt – Arithmetic expressions and conditionals
   • (e) t5.txt – Complex types (union, record, typedef)
   • (f) t6.txt – Syntax error test case
   • (g) testcase.txt – If-else (maximum of two numbers)
   • (h) testcase7.txt – Average of two numbers

6. Executable / Driver

   • (a) driver.c – Entry point integrating lexer and parser

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Core Components

1. Trie (Keyword Recognition)

• Efficient keyword lookup using character-based tree
• Supports:
  • insertKeyword()
  • searchKeyword()

2. FIRST & FOLLOW Computation

• Recursive computation of FIRST sets
• Dependency-based resolution for FOLLOW sets
• Handles:
  • Epsilon productions
  • Multi-rule grammars

3. Grammar Specification

• Grammar is hardcoded using structures
• Each non-terminal maps to production rules
• Supports:
  • Terminals and Non-terminals
  • Multiple productions
  • Epsilon handling

4. String Utilities

• Custom implementation of string comparison
• Avoids use of standard library functions

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Test Cases

File	Description
t1.txt	Lexer stress test (invalid syntax)
t2.txt	Sum of N numbers
t3.txt	Record handling & averaging
t4.txt	Arithmetic + conditionals
t5.txt	Complex types (union, record, typedef)
t6.txt	Syntax error test
testcase.txt	If-else maximum program
testcase7.txt	Average of two numbers

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How to Run

1. Compile

gcc *.c -o compiler

2.Run

./compiler <input_file>

Example: ./compiler t2.txt