diff --git a/lang/ast/expr/arith.c b/lang/ast/expr/arith.c
index 6fb3802..729204f 100644
--- a/lang/ast/expr/arith.c
+++ b/lang/ast/expr/arith.c
@@ -696,10 +696,23 @@ struct token_parse_result arith_parse_left_bracket(
 		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
 	}
 
-	if (state->s_prev_component == EXPR_CMP_OPERAND) {
-		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
+	if (state->s_prev_component == EXPR_CMP_OPERAND || state->s_prev_component == EXPR_CMP_MSG) {
+		/* subscript operator */
+
+		state->s_prev_token = IVY_SYM_LEFT_BRACKET;
+		struct ivy_ast_op_node *subscript = (struct ivy_ast_op_node *)ast_node_create(IVY_AST_OP);
+		subscript->n_op = ivy_operator_get_by_id(IVY_OP_SUBSCRIPT);
+		arith_push_operator(state, (struct ivy_ast_node *)subscript);
+
+		struct expr_parser_state *index = (struct expr_parser_state *)parser_push_state(ctx, IVY_AST_EXPR, 0);
+		expr_add_terminator(index, IVY_SYM_RIGHT_BRACKET);
+		index->s_subexpr_depth = state->s_subexpr_depth + 1;
+
+		return PARSE_RESULT(IVY_OK, 0);
 	}
 
+	/* lambda */
+
 	state->s_prev_token = IVY_SYM_LEFT_BRACKET;
 	state->s_type = EXPR_TYPE_ARITH;
 
@@ -713,6 +726,11 @@ struct token_parse_result arith_parse_right_bracket(
 	struct expr_parser_state *state
 		= parser_get_state(ctx, struct expr_parser_state);
 
+	if (state->s_prev_token == IVY_SYM_LEFT_BRACKET) {
+		/* we've just parsed a subscript operator. nothing further to do here. */
+		return PARSE_RESULT(IVY_OK, 0);
+	}
+
 	state->s_prev_token = IVY_SYM_RIGHT_BRACKET;
 	struct token_parse_result result = expr_finalise_and_return(ctx, state);
 	result.r_flags = PARSE_REPEAT_TOKEN;
diff --git a/lang/include/ivy/lang/operator.h b/lang/include/ivy/lang/operator.h
index 5b31154..89bcbc8 100644
--- a/lang/include/ivy/lang/operator.h
+++ b/lang/include/ivy/lang/operator.h
@@ -78,6 +78,7 @@ enum ivy_operator_id {
 	IVY_OP_UNDERSTANDS,
 	IVY_OP_SELF_ACCESS,
 	IVY_OP_PKG_ACCESS,
+	IVY_OP_SUBSCRIPT,
 
 	/* these are not real operators, and are just used internally by the parser. */
 	IVY_OP_MSG,
diff --git a/lang/operator.c b/lang/operator.c
index 8436aeb..8663c09 100644
--- a/lang/operator.c
+++ b/lang/operator.c
@@ -55,6 +55,7 @@ static const struct ivy_operator operators[] = {
 	OP(UNDERSTANDS,		IS,		LEFT,	INFIX,		BINARY),
 	OP(SELF_ACCESS,		SUBSCRIPT,	LEFT,	INFIX,		BINARY),
 	OP(PKG_ACCESS,		SUBSCRIPT,	LEFT,	INFIX,		BINARY),
+	OP(SUBSCRIPT,		SUBSCRIPT,	LEFT,	INFIX,		BINARY),
 
 	/* parser-internal pseudo-operators. */
 	OP(MSG,			UNARY_MSG,	LEFT,	POSTFIX,	UNARY),
@@ -201,6 +202,7 @@ const char *ivy_operator_id_to_string(enum ivy_operator_id op)
 		ENUM_STR(IVY_OP_UNDERSTANDS);
 		ENUM_STR(IVY_OP_SELF_ACCESS);
 		ENUM_STR(IVY_OP_PKG_ACCESS);
+		ENUM_STR(IVY_OP_SUBSCRIPT);
 		ENUM_STR(IVY_OP_MSG);
 		ENUM_STR(IVY_OP_LEFT_PAREN);
 	default: