From e2984c27ab2a915037fc0d9aaa9426894a7ad781 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Fri, 19 Jun 2026 18:37:51 +0100
Subject: Add lowerCamelCaseToUpperCase

---
 .../zwobble/hobgoblin/compiler/util/Casing.java    | 16 ++++++++++++++++
 .../hobgoblin/compiler/util/CasingTests.java       | 22 ++++++++++++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100644 src/test/java/org/zwobble/hobgoblin/compiler/util/CasingTests.java

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/util/Casing.java b/src/main/java/org/zwobble/hobgoblin/compiler/util/Casing.java
index 80b8459..1b962a4 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/util/Casing.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/util/Casing.java
@@ -8,4 +8,20 @@ public class Casing {
     public static String lowerCamelCaseToUpperCamelCase(String name) {
         return name.substring(0, 1).toUpperCase(Locale.ROOT) + name.substring(1);
     }
+
+    public static String lowerCamelCaseToUpperCase(String lowerCamelCase) {
+        var upperCase = new StringBuilder();
+
+        for (var characterIndex = 0; characterIndex < lowerCamelCase.length(); characterIndex++) {
+            var character = lowerCamelCase.charAt(characterIndex);
+            if (Character.isUpperCase(character)) {
+                upperCase.append('_');
+                upperCase.append(character);
+            } else {
+                upperCase.append(Character.toUpperCase(character));
+            }
+        }
+
+        return upperCase.toString();
+    }
 }
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/util/CasingTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/util/CasingTests.java
new file mode 100644
index 0000000..1441811
--- /dev/null
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/util/CasingTests.java
@@ -0,0 +1,22 @@
+package org.zwobble.hobgoblin.compiler.util;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.equalTo;
+
+public class CasingTests {
+    @ParameterizedTest
+    @CsvSource({
+        "a,A",
+        "abc,ABC",
+        "abcDef,ABC_DEF",
+        "abDeFg,AB_DE_FG",
+    })
+    public void lowerCamelCaseToUpperCase(String lowerCamelCase, String expectedUpperCase) {
+        var result = Casing.lowerCamelCaseToUpperCase(lowerCamelCase);
+
+        assertThat(result, equalTo(expectedUpperCase));
+    }
+}
-- 
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