X-Git-Url: https://git.ayoreis.com/zlox.git/blobdiff_plain/6ae8b98923f9b393fbfa25db8af61a9bd6f1b0f6..f1f777199093f609b87f8e334589e9f0283249da:/src/Environment.zig?ds=inline

diff --git a/src/Environment.zig b/src/Environment.zig
index 25744a7..40a396a 100644
--- a/src/Environment.zig
+++ b/src/Environment.zig
@@ -6,17 +6,28 @@ const Literal = Token.Literal;
 const Environment = @This();
 const ErrorPayload = @import("Interpreter.zig").ErrorPayload;
 
+enclosing: ?*Environment,
 values: StringHashMapUnmanaged(Literal) = .empty,
 
+pub fn init(enclosing: ?*Environment) Environment {
+    return .{
+        .enclosing = enclosing,
+    };
+}
+
 pub fn define(self: *Environment, allocator: Allocator, name: []const u8, value: Literal) !void {
     try self.values.put(allocator, name, value);
 }
 
 pub fn get(self: *Environment, allocator: Allocator, name: Token, err_payload: *ErrorPayload) !Literal {
-    return self.values.get(name.lexeme) orelse {
-        err_payload.* = .{ .token = name, .message = try std.fmt.allocPrint(allocator, "Undefined variable '{s}'.", .{name.lexeme}) };
-        return error.RuntimeError;
-    };
+    if (self.values.contains(name.lexeme)) {
+        return self.values.get(name.lexeme).?;
+    }
+
+    if (self.enclosing) |enclosing| return enclosing.get(allocator, name, err_payload);
+
+    err_payload.* = .{ .token = name, .message = try std.fmt.allocPrint(allocator, "Undefined variable '{s}'.", .{name.lexeme}) };
+    return error.RuntimeError;
 }
 
 pub fn assign(self: *Environment, allocator: Allocator, name: Token, value: Literal, err_payload: *ErrorPayload) !void {
@@ -25,6 +36,11 @@ pub fn assign(self: *Environment, allocator: Allocator, name: Token, value: Lite
         return;
     }
 
+    if (self.enclosing) |enclosing| {
+        try enclosing.assign(allocator, name, value, err_payload);
+        return;
+    }
+
     err_payload.* = .{ .token = name, .message = try std.fmt.allocPrint(allocator, "Undefined variable '{s}'.", .{name.lexeme}) };
     return error.RuntimeError;
 }