From f72501fde2f1156a95b97d65a90df2714d20008e Mon Sep 17 00:00:00 2001
From: Tibo De Peuter <tibo.depeuter@ugent.be>
Date: Thu, 27 Mar 2025 11:04:31 +0100
Subject: [PATCH] feat(lexer): Scan empty string

---
 src/lexer/Lexer.kt           | 11 +++++++++++
 src/lexer/LexerPosition.kt   |  5 +++++
 src/lexer/Token.kt           |  8 ++++++++
 src/lexer/TokenType.kt       |  5 +++++
 tests/lexer/LexerScanTest.kt | 16 ++++++++++++++++
 5 files changed, 45 insertions(+)
 create mode 100644 src/lexer/Lexer.kt
 create mode 100644 src/lexer/LexerPosition.kt
 create mode 100644 src/lexer/Token.kt
 create mode 100644 src/lexer/TokenType.kt
 create mode 100644 tests/lexer/LexerScanTest.kt

diff --git a/src/lexer/Lexer.kt b/src/lexer/Lexer.kt
new file mode 100644
index 0000000..93a9d5c
--- /dev/null
+++ b/src/lexer/Lexer.kt
@@ -0,0 +1,11 @@
+package lexer
+
+class Lexer {
+    fun scan(source: String): List<Token> {
+        if (source.isEmpty()) {
+            return listOf(Token(TokenType.EOF, LexerPosition(1, 1, 0)))
+        }
+
+        return emptyList()
+    }
+}
diff --git a/src/lexer/LexerPosition.kt b/src/lexer/LexerPosition.kt
new file mode 100644
index 0000000..2ca10bc
--- /dev/null
+++ b/src/lexer/LexerPosition.kt
@@ -0,0 +1,5 @@
+package lexer
+
+class LexerPosition(val line: Int, val column: Int, val length: Int) {
+    // Do nothing
+}
diff --git a/src/lexer/Token.kt b/src/lexer/Token.kt
new file mode 100644
index 0000000..e7f1727
--- /dev/null
+++ b/src/lexer/Token.kt
@@ -0,0 +1,8 @@
+package lexer
+
+class Token(
+    val type: TokenType,
+    val position: LexerPosition
+) {
+    // Do nothing
+}
diff --git a/src/lexer/TokenType.kt b/src/lexer/TokenType.kt
new file mode 100644
index 0000000..bace57e
--- /dev/null
+++ b/src/lexer/TokenType.kt
@@ -0,0 +1,5 @@
+package lexer
+
+enum class TokenType {
+    EOF
+}
diff --git a/tests/lexer/LexerScanTest.kt b/tests/lexer/LexerScanTest.kt
new file mode 100644
index 0000000..d2ff248
--- /dev/null
+++ b/tests/lexer/LexerScanTest.kt
@@ -0,0 +1,16 @@
+package be.ugent.logprog.lexer
+
+import lexer.Lexer
+import lexer.TokenType
+import org.junit.jupiter.api.Test
+import kotlin.test.assertEquals
+
+class LexerScanTest {
+    @Test
+    fun scan_emptyString_returnsEOF() {
+        val lexer = Lexer()
+        val tokens = lexer.scan("")
+        assertEquals(1, tokens.size)
+        assertEquals(TokenType.EOF, tokens[0].type)
+    }
+}