compiler: add local scope basics

src/compiler.zig

@@ -113,6 +113,11 @@ var rules = []ParseRule{
     ParseRule{},
 };
 
+pub const Local = struct {
+    name: tokens.Token,
+    depth: i32,
+};
+
 pub const Compiler = struct {
     src: []const u8,
     stdout: vm.StdOut,
@@ -123,6 +128,10 @@ pub const Compiler = struct {
     debug_flag: bool = false,
     vmach: *vm.VM,
 
+    locals: [256]Local,
+    localCount: u8 = 0,
+    scopeDepth: u8 = 0,
+
     pub fn init(
         allocator: *Allocator,
         chunk: *chunks.Chunk,
@@ -139,6 +148,12 @@ pub const Compiler = struct {
             .parser = Parser{},
             .debug_flag = debug_flag,
             .vmach = vmach,
+
+            // local variable resolution
+            .locals = []Local{Local{
+                .name = Token{},
+                .depth = -1,
+            }} ** 256,
         };
     }