diff --git a/clox/src/common.h b/clox/src/common.h
index 25fc22f..5cd0cf4 100644
--- a/clox/src/common.h
+++ b/clox/src/common.h
@@ -8,4 +8,6 @@
 #define DEBUG_PRINT_CODE
 #define DEBUG_TRACE_EXECUTION
 
+#define UINT8_COUNT (UINT8_MAX + 1)
+
 #endif
diff --git a/clox/src/compiler.c b/clox/src/compiler.c
index 0fc41b8..6a20a20 100644
--- a/clox/src/compiler.c
+++ b/clox/src/compiler.c
@@ -38,7 +38,19 @@ typedef struct {
   Precedence precedence;
 } ParseRule;
 
+typedef struct {
+  Token name;
+  int depth;
+} Local;
+
+typedef struct {
+  Local locals[UINT8_COUNT];
+  int localCount;
+  int scopeDepth;
+} Compiler;
+
 Parser parser;
+Compiler *current = NULL;
 Chunk *compilingChunk;
 
 static Chunk *currentChunk() { return compilingChunk; }
@@ -122,6 +134,12 @@ static void emitConstant(Value value) {
   emitBytes(OP_CONSTANT, makeConstant(value));
 }
 
+static void initCompiler(Compiler *compiler) {
+  compiler->localCount = 0;
+  compiler->scopeDepth = 0;
+  current = compiler;
+}
+
 static void endCompiler() {
   emitReturn();
 #ifdef DEBUG_PRINT_CODE
@@ -398,6 +416,8 @@ static ParseRule *getRule(TokenType type) { return &rules[type]; }
 
 bool compile(const char *source, Chunk *chunk) {
   initScanner(source);
+  Compiler compiler;
+  initCompiler(&compiler);
   compilingChunk = chunk;
 
   parser.hadError = false;