xiiregexbuilder

commit 88f2f9885887916d3d699c62abc091396341bdec
parent e7faebb6ba14f20418524dd98261081bffad9d60
Author: Pranav Prabhu Kumble <kumblepranavprabhu@gmail.com>
Date:   Thu, 26 Mar 2026 14:36:55 +0530

Week 2: Implement Lexer (Part 1: Initial definitions)

Diffstat:
A
src/lexer.cpp
 | 
26
++++++++++++++++++++++++++
A
src/lexer.h
 | 
15
+++++++++++++++

2 files changed, 41 insertions(+), 0 deletions(-)
diff --git a/src/lexer.cpp b/src/lexer.cpp
@@ -0,0 +1,26 @@
+#include "lexer.h"
+#include <stdexcept>
+
+std::string tokenTypeToString(TokenType type) {
+    switch (type) {
+        case TokenType::LITERAL:   return "LITERAL";
+        case TokenType::DOT:       return "DOT";
+        case TokenType::STAR:      return "STAR";
+        case TokenType::PLUS:      return "PLUS";
+        case TokenType::QUESTION:  return "QUESTION";
+        case TokenType::PIPE:      return "PIPE";
+        case TokenType::LPAREN:    return "LPAREN";
+        case TokenType::RPAREN:    return "RPAREN";
+        case TokenType::END_OF_INPUT: return "END_OF_INPUT";
+        default:                   return "UNKNOWN";
+    }
+}
+
+Lexer::Lexer(const std::string& input, int lineNum)
+    : input(input), pos(0), line(lineNum), col(1) {}
+
+char Lexer::peek() const {
+    if (isAtEnd()) return '\0';
+    return input[pos];
+}
+
diff --git a/src/lexer.h b/src/lexer.h
@@ -0,0 +1,15 @@
+#ifndef LEXER_H
+#define LEXER_H
+
+#include <string>
+#include <vector>
+#include <ostream>
+
+enum class TokenType {
+    LITERAL,
+    DOT,
+    STAR,
+    PLUS,
+    QUESTION,
+    PIPE,
+    LPAREN,