Add support for subscript operations on objects

debug/app.ona

@@ -8,9 +8,14 @@ options = {
 	.tick_rate = 60,
 
 	["foo"] = "bar",
-	[42] = 42,
+	[42] = "42",
 }
 
+options["foo"] = "rab"
+options[42] = "24"
+
 @log_info(options.title)
+@log_info(options["foo"])
+@log_info(options[42])
 
 return options

source/ona/kym.zig

@@ -222,6 +222,19 @@ pub const RuntimeEnv = struct {
 						try self.compile_expression(chunk, field_set.value_expression.*);
 						try chunk.opcodes.push_one(.object_set);
 					},
+
+					.subscript_get => |subscript_get| {
+						try self.compile_expression(chunk, subscript_get.object_expression.*);
+						try self.compile_expression(chunk, subscript_get.subscript_expression.*);
+						try chunk.opcodes.push_one(.object_get);
+					},
+
+					.subscript_set => |subscript_set| {
+						try self.compile_expression(chunk, subscript_set.object_expression.*);
+						try self.compile_expression(chunk, subscript_set.subscript_expression.*);
+						try self.compile_expression(chunk, subscript_set.value_expression.*);
+						try chunk.opcodes.push_one(.object_set);
+					},
 				}
 			}
 

source/ona/kym/Ast.zig

@@ -33,6 +33,17 @@ pub const Expression = union (enum) {
 		value_expression: *Expression,
 	},
 
+	subscript_get: struct {
+		object_expression: *Expression,
+		subscript_expression: *Expression,
+	},
+
+	subscript_set: struct {
+		object_expression: *Expression,
+		subscript_expression: *Expression,
+		value_expression: *Expression,
+	},
+
 	binary_operation: struct {
 		operator: BinaryOperator,
 		lhs_expression: *Expression,
@@ -266,6 +277,14 @@ pub fn parse_expression(self: *Self) ParseError!Expression {
 				},
 			},
 
+			.subscript_get => |subscript_get| .{
+				.subscript_set = .{
+					.object_expression = subscript_get.object_expression,
+					.subscript_expression = subscript_get.subscript_expression,
+					.value_expression = try coral.io.allocate_one(allocator, try self.parse_expression()),
+				},
+			},
+
 			else => self.report("expected local or field on left-hand side of expression"),
 		};
 	}
@@ -388,10 +407,10 @@ fn parse_factor(self: *Self) ParseError!Expression {
 						.symbol_bracket_left => {
 							self.tokenizer.step();
 
-							const index_expression = try self.parse_expression();
+							const subscript_expression = try self.parse_expression();
 
 							if (self.tokenizer.token != .symbol_bracket_right) {
-								return self.report("expected `]` expression");
+								return self.report("expected `]` after subscript expression");
 							}
 
 							self.tokenizer.skip_newlines();
@@ -404,7 +423,7 @@ fn parse_factor(self: *Self) ParseError!Expression {
 
 							try table_literal.push_one(.{
 								.value_expression = try self.parse_expression(),
-								.key_expression = index_expression,
+								.key_expression = subscript_expression,
 							});
 
 							switch (self.tokenizer.token) {
@@ -481,6 +500,26 @@ fn parse_factor(self: *Self) ParseError!Expression {
 				self.tokenizer.skip_newlines();
 			},
 
+			.symbol_bracket_left => {
+				self.tokenizer.skip_newlines();
+
+				// TODO: Remove when Zig fixes miscompilation with in-place struct re-assignment.
+				const unnecessary_temp = try coral.io.allocate_one(allocator, expression);
+
+				expression = .{
+					.subscript_get = .{
+						.subscript_expression = try coral.io.allocate_one(allocator, try self.parse_expression()),
+						.object_expression = unnecessary_temp,
+					},
+				};
+
+				if (self.tokenizer.token != .symbol_bracket_right) {
+					return self.report("expected `]` subscript expression");
+				}
+
+				self.tokenizer.skip_newlines();
+			},
+
 			.symbol_paren_left => {
 				var argument_expressions = Expression.List.make(allocator);