discover/grub2: Use subclass-style structs for AST

Use embedded 'struct grub2_statement' data to create a subclass-style
syntax tree of statements.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

1 files changed, 18 insertions, 20 deletions

diff --git a/discover/grub2/grub2.h b/discover/grub2/grub2.h
index cc817ff..0643a72 100644
--- a/discover/grub2/grub2.h
+++ b/discover/grub2/grub2.h
@@ -18,45 +18,43 @@ struct grub2_argv {
 	struct list		words;
 };
 
+struct grub2_statements {
+	struct list		list;
+};
+
+struct grub2_statement {
+	struct list_item	list;
+	enum {
+		STMT_TYPE_SIMPLE,
+		STMT_TYPE_MENUENTRY,
+		STMT_TYPE_IF,
+		STMT_TYPE_BLOCK,
+	} type;
+};
+
 struct grub2_statement_simple {
+	struct grub2_statement	st;
 	struct grub2_argv	*argv;
 };
 
 struct grub2_statement_menuentry {
+	struct grub2_statement	st;
 	struct grub2_argv	*argv;
 	struct grub2_statements	*statements;
 };
 
 struct grub2_statement_if {
+	struct grub2_statement	st;
 	struct grub2_statement	*condition;
 	struct grub2_statements	*true_case;
 	struct grub2_statements	*false_case;
 };
 
 struct grub2_statement_block {
+	struct grub2_statement	st;
 	struct grub2_statements	*statements;
 };
 
-struct grub2_statement {
-	struct list_item	list;
-	enum {
-		STMT_TYPE_SIMPLE,
-		STMT_TYPE_MENUENTRY,
-		STMT_TYPE_IF,
-		STMT_TYPE_BLOCK,
-	} type;
-	union {
-		struct grub2_statement_simple		simple;
-		struct grub2_statement_menuentry	menuentry;
-		struct grub2_statement_if		ifstmt;
-		struct grub2_statement_block		block;
-	};
-};
-
-struct grub2_statements {
-	struct list		list;
-};
-
 struct grub2_parser {
 	void			*scanner;
 	struct grub2_statements	*statements;