compiler: add scope support

src/compiler.zig

@@ -244,6 +244,14 @@ pub const Compiler = struct {
         }
     }
 
+    fn beginScope(self: *Compiler) void {
+        self.scopeDepth += 1;
+    }
+
+    fn endScope(self: *Compiler) void {
+        self.scopeDepth -= 1;
+    }
+
     fn grouping(self: *Compiler, canAssign: bool) !void {
         try self.expression();
         try self.consume(.RIGHT_PAREN, "Expect ')' after expression.");
@@ -456,7 +464,7 @@ pub const Compiler = struct {
         try self.defineVariable(global);
     }
 
-    fn declaration(self: *Compiler) !void {
+    fn declaration(self: *Compiler) anyerror!void {
         if (try self.match(.VAR)) {
             try self.varDecl();
         } else {
@@ -465,9 +473,21 @@ pub const Compiler = struct {
         if (self.parser.panicMode) try self.synchronize();
     }
 
+    fn block(self: *Compiler) anyerror!void {
+        while (!self.check(.RIGHT_BRACE) and !self.check(.EOF)) {
+            try self.declaration();
+        }
+
+        try self.consume(.RIGHT_BRACE, "Expect '}' after block.");
+    }
+
     fn statement(self: *Compiler) !void {
         if (try self.match(.PRINT)) {
             try self.printStmt();
+        } else if (try self.match(.LEFT_BRACE)) {
+            self.beginScope();
+            try self.block();
+            self.endScope();
         } else {
             try self.exprStmt();
         }