lang: ast: re-factor parser into multiple files

lang/ast/unit.c

@@ -0,0 +1,30 @@
+#include "ctx.h"
+#include "node.h"
+#include "unit-package.h"
+
+static enum ivy_status parse_package_keyword(
+	struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	parser_push_state(
+		ctx, IVY_AST_UNIT_PACKAGE, struct ivy_ast_unit_package_node,
+		struct unit_package_parser_state);
+	return IVY_OK;
+}
+
+static enum ivy_status add_child(
+	struct ivy_ast_node *parent, struct ivy_ast_node *child)
+{
+	return IVY_OK;
+}
+
+static void print(struct ivy_ast_node *node)
+{
+}
+
+struct ast_node_type unit_node_ops = {
+	.n_add_child = add_child,
+        .n_print = print,
+        .n_keyword_parsers = {
+		[IVY_KW_PACKAGE] = parse_package_keyword,
+	},
+};