dynamic lookups

include/lang2/bytecode.h

@@ -149,20 +149,37 @@ enum l2_opcode {
 	L2_OP_NAMESPACE_LOOKUP,
 
 	/*
-	 * Look up a value from an array; direct_array_lookup <key>
-	 * Pop <val>
+	 * Look up a value from an array; array_lookup <key>
 	 * Pop <arr>
-	 * Assign <val> to <arr[<key>]>
+	 * Push <arr[<key>]>
 	 */
 	L2_OP_ARRAY_LOOKUP,
 
 	/*
-	 * Set a value in an array; direct_array_set <key>
+	 * Set a value in an array; array_set <key>
+	 * Read <val>
 	 * Read <arr>
-	 * Push <arr[<key>]>
+	 * Assign <val> to <arr[<key>]>
 	 */
 	L2_OP_ARRAY_SET,
 
+	/*
+	 * Look up a runtime value in an array or object.
+	 * Pop <key>
+	 * Pop <container>
+	 * Push <container[<key>]>
+	 */
+	L2_OP_DYNAMIC_LOOKUP,
+
+	/*
+	 * Set a value in an array or object.
+	 * Pop <val>
+	 * Pop <key>
+	 * Pop <arr>
+	 * Assign <val> to <arr[<key>]>
+	 */
+	L2_OP_DYNAMIC_SET,
+
 	/*
 	 * Halt execution.
 	 */

include/lang2/gen/gen.h

@@ -38,6 +38,8 @@ void l2_gen_namespace_set(struct l2_generator *gen, char **ident);
 void l2_gen_namespace_lookup(struct l2_generator *gen, char **ident);
 void l2_gen_array_lookup(struct l2_generator *gen, int number);
 void l2_gen_array_set(struct l2_generator *gen, int number);
+void l2_gen_dynamic_lookup(struct l2_generator *gen);
+void l2_gen_dynamic_set(struct l2_generator *gen);
 void l2_gen_stack_frame_lookup(struct l2_generator *gen, char **ident);
 void l2_gen_stack_frame_set(struct l2_generator *gen, char **ident);
 void l2_gen_stack_frame_replace(struct l2_generator *gen, char **ident);

lib/gen/gen.c

@@ -142,6 +142,14 @@ void l2_gen_array_set(struct l2_generator *gen, int number) {
 	put(gen, number);
 }
 
+void l2_gen_dynamic_lookup(struct l2_generator *gen) {
+	put(gen, L2_OP_DYNAMIC_LOOKUP);
+}
+
+void l2_gen_dynamic_set(struct l2_generator *gen) {
+	put(gen, L2_OP_DYNAMIC_SET);
+}
+
 void l2_gen_stack_frame_lookup(struct l2_generator *gen, char **ident) {
 	size_t atom_id = l2_strset_put(&gen->atomset, ident);
 	put(gen, L2_OP_STACK_FRAME_LOOKUP);

lib/parse/parse.c

@@ -327,6 +327,32 @@ static int parse_arg_level_expression(
 			l2_lexer_consume(lexer); // dot-number
 
 			l2_gen_array_lookup(gen, number);
+		} else if (tok->kind == L2_TOK_PERIOD && tok2->kind == L2_TOK_OPEN_PAREN) {
+			l2_trace_scope("dynamic lookup");
+			l2_lexer_consume(lexer); // '.'
+			l2_lexer_consume(lexer); // '('
+
+			if (parse_expression(lexer, gen, err) < 0) {
+				return -1;
+			}
+
+			if (l2_lexer_peek(lexer, 1)->kind != L2_TOK_CLOSE_PAREN) {
+				l2_parse_err(err, tok, "Expected '(', got %s",
+						l2_token_kind_name(tok->kind));
+				return -1;
+			}
+			l2_lexer_consume(lexer); // ')'
+
+			if (l2_lexer_peek(lexer, 1)->kind == L2_TOK_EQUALS) {
+				l2_lexer_consume(lexer); // '='
+				if (parse_expression(lexer, gen, err) < 0) {
+					return -1;
+				}
+
+				l2_gen_dynamic_set(gen);
+			} else {
+				l2_gen_dynamic_lookup(gen);
+			}
 		} else {
 			break;
 		}

lib/vm/print.c

@@ -211,6 +211,14 @@ void l2_vm_print_op(l2_word *ops, size_t opcount, size_t *ptr) {
 		printf("ARRAY_SET %08x\n", ops[(*ptr)++]);
 		return;
 
+	case L2_OP_DYNAMIC_LOOKUP:
+		printf("DYNAMIC_LOOKUP\n");
+		return;
+
+	case L2_OP_DYNAMIC_SET:
+		printf("DYNAMIC_SET\n");
+		return;
+
 	case L2_OP_HALT:
 		printf("HALT\n");
 		return;

lib/vm/vm.c

@@ -451,6 +451,55 @@ void l2_vm_step(struct l2_vm *vm) {
 		}
 		break;
 
+	case L2_OP_DYNAMIC_LOOKUP:
+		{
+			l2_word key_id = vm->stack[--vm->sptr];
+			l2_word container_id = vm->stack[--vm->sptr];
+
+			struct l2_vm_value *key = &vm->values[key_id];
+			struct l2_vm_value *container = &vm->values[container_id];
+			if (
+					l2_vm_value_type(key) == L2_VAL_TYPE_REAL &&
+					l2_vm_value_type(container) == L2_VAL_TYPE_ARRAY) {
+				// TODO: Error if out of bounds
+				vm->stack[vm->sptr++] = container->array->data[(size_t)key->real];
+			} else if (
+					l2_vm_value_type(key) == L2_VAL_TYPE_ATOM &&
+					l2_vm_value_type(container) == L2_VAL_TYPE_NAMESPACE) {
+				// TODO: Error if out of bounds
+				vm->stack[vm->sptr++] = l2_vm_namespace_get(vm, container, key->atom);
+			} else {
+				// TODO: error
+			}
+		}
+		break;
+
+	case L2_OP_DYNAMIC_SET:
+		{
+			l2_word val = vm->stack[--vm->sptr];
+			l2_word key_id = vm->stack[--vm->sptr];
+			l2_word container_id = vm->stack[--vm->sptr];
+			vm->stack[vm->sptr++] = val;
+
+			struct l2_vm_value *key = &vm->values[key_id];
+			struct l2_vm_value *container = &vm->values[container_id];
+
+			if (
+					l2_vm_value_type(key) == L2_VAL_TYPE_REAL &&
+					l2_vm_value_type(container) == L2_VAL_TYPE_ARRAY) {
+				// TODO: Error if out of bounds
+				container->array->data[(size_t)key->real] = val;
+			} else if (
+					l2_vm_value_type(key) == L2_VAL_TYPE_ATOM &&
+					l2_vm_value_type(container) == L2_VAL_TYPE_NAMESPACE) {
+				// TODO: Error if out of bounds
+				l2_vm_namespace_set(container, key->atom, val);
+			} else {
+				// TODO: error
+			}
+		}
+		break;
+
 	case L2_OP_HALT:
 		break;
 	}

test/examples/dynamic-lookups.l2

@@ -0,0 +1,16 @@
+idx := 0
+arr := [100 20 30]
+print arr.(idx)
+
+arr.(+ idx 1) = 50
+print arr
+
+print [10 20 30].(+ 1 1)
+
+obj := {}
+obj.('hello) = "what's up"
+print obj.hello
+
+get-ident := {'foo}
+obj.(get-ident()) = 100
+print obj.foo

test/examples/dynamic-lookups.l2.expected

@@ -0,0 +1,5 @@
+100
+[100 50 30]
+30
+what's up
+100

test/src/examples.t.c

@@ -132,6 +132,7 @@ describe(exaples) {
 	check("namespaces.l2");
 	check("arrays.l2");
 	check("functions.l2");
+	check("dynamic-lookups.l2");
 
 	if (error_message != NULL) {
 		free(error_message);