diff --git a/grammars/c23/common.bnf b/grammars/c23/common.bnf
deleted file mode 100644
index 0014d31..0000000
--- a/grammars/c23/common.bnf
+++ /dev/null
@@ -1,14 +0,0 @@
-
-comment = "\/\/[^\n]*|\/\*[\s\S]*?\*\/";
-whitespace = '\s+';
-
-##ignore comment whitespace
-
-# String and character constants
-
-# Due to comments handling, we need to have a literal for the entire character constant
-character_constant = "(u8|u|U|L)?'([^'\\\n]|\\['\"\\?abfnrtv]|\\[0-7]{1,3}|\\x[0-9A-Fa-f]+|\\u[0-9A-Fa-f]{4}|\\U[0-9A-Fa-f]{8})*'";
-
-string_literal = '(u8|u|U|L)?"([^"\\\n]|\\["\'\\?abfnrtv]|\\[0-7]{1,3}|\\x[0-9A-Fa-f]+|\\u[0-9A-Fa-f]{4}|\\U[0-9A-Fa-f]{8})*"';
-
-quote = "'";
diff --git a/grammars/c23/language.bnf b/grammars/c23/language.bnf
index f799e14..7c71a51 100644
--- a/grammars/c23/language.bnf
+++ b/grammars/c23/language.bnf
@@ -1,4 +1,17 @@
-##include common.bnf
+
+comment = "\/\/[^\n]*|\/\*[\s\S]*?\*\/";
+whitespace = '\s+';
+
+##ignore comment whitespace
+
+# String and character constants
+
+# Due to comments handling, we need to have a literal for the entire character constant
+character_constant = "(u8|u|U|L)?'([^'\\\n]|\\['\"\\?abfnrtv]|\\[0-7]{1,3}|\\x[0-9A-Fa-f]+|\\u[0-9A-Fa-f]{4}|\\U[0-9A-Fa-f]{8})*'";
+
+string_literal = '(u8|u|U|L)?"([^"\\\n]|\\["\'\\?abfnrtv]|\\[0-7]{1,3}|\\x[0-9A-Fa-f]+|\\u[0-9A-Fa-f]{4}|\\U[0-9A-Fa-f]{8})*"';
+
+quote = "'";
 
 token =
 | keyword
@@ -100,7 +113,17 @@ enumeration_constant = identifier;
 
 predefined_constant = "false" | "true" | "nullptr";
 
-##include punctuator.bnf
+# `punctuator` minus things used later (e.g. "any pp-token other than ...")
+__punctuator_base = "\." | "\+\+" | "--" | "&" | "\*" | "\+" | "-" | "~" | "!"
+| "/" | "%" | "==" | "!=" | "\^" | "\|" | "&&" | "\|\|" | "\?" | ":" | "::" | ";" | "\.\.\."
+| "=" | "\*=" | "/=" | "%=" | "\+=" | "-=" | "&=" | "\^=" | "\|="
+| "," | "##" | "%:" | "%:%:";
+
+__punctuator_left_angle_brackets = "<<" | "<" | "<=" | "<<=" | "<:" | "<%";
+__punctuator_angle_brackets = __punctuator_left_angle_brackets | ">>" | ">" | ">=" | ">>=" | ":>" | "%>" | "->";
+__punctuator_grouping = "\[" | "\]" | "\(" | "\)" | "\{" | "\}";
+
+punctuator =  __punctuator_base | __punctuator_angle_brackets | __punctuator_grouping;
 
 primary_expression =
 | identifier
@@ -113,7 +136,6 @@ generic_selection = "_Generic" "\(" assignment_expression "," generic_assoc_list
 
 generic_assoc_list = generic_association {"," generic_association};
 
-
 generic_association = (type_name | "default") ":" assignment_expression;
 
 postfix_expression =
@@ -356,7 +378,7 @@ designator_list = designator*;
 
 designator =
 | ("\[" constant_expression "\]")
-| ("." identifier);
+| ("\." identifier);
 
 static_assert_declaration = "static_assert" "\(" constant_expression ["," string_literal] "\)" ";";
 
diff --git a/grammars/c23/preprocessing.bnf b/grammars/c23/preprocessing.bnf
index 972dabc..0293748 100644
--- a/grammars/c23/preprocessing.bnf
+++ b/grammars/c23/preprocessing.bnf
@@ -1,6 +1,4 @@
-##include common.bnf
-
-##root group_part
+##include language.bnf
 
 group_part =
 | control_line
@@ -10,23 +8,21 @@ group_part =
 
 if_section = if_group elif_group* else_group? endif_line;
 
-if_group = "#" (
-| ("if\b" constant_expression group_part*)
-| ("ifdef\b" identifier group_part*)
-| ("ifndef\b" identifier group_part*)
-);
+if_group =
+| ("#if\b" constant_expression group_part*)
+| ("#ifdef\b" identifier group_part*)
+| ("#ifndef\b" identifier group_part*);
 ##groups if_group %#if %#ifdef %#ifndef
 
-elif_group = "#" (
-| ("elif\b" constant_expression group_part*)
-| ("elifdef\b" identifier group_part*)
-| ("elifndef\b" identifier group_part*)
-);
+elif_group =
+| ("#elif\b" constant_expression group_part*)
+| ("#elifdef\b" identifier group_part*)
+| ("#elifndef\b" identifier group_part*);
 ##groups elif_group %#elif %#elifdef %#elifndef
 
-else_group = "#" "else\b" group_part*;
+else_group = "#else\b" group_part*;
 
-endif_line = "#" "endif\b";
+endif_line = "#endif\b";
 
 control_line = "#" (
 | ("include\b" header_name)
@@ -159,4 +155,4 @@ pp_number = "\.?[0-9](['\w]|(e|E|p|P)(\+|-)|\.)*";
 
 identifier = "[_a-zA-Z]\w*";
 
-##include punctuator.bnf
\ No newline at end of file
+##override_root group_part
diff --git a/grammars/c23/punctuator.bnf b/grammars/c23/punctuator.bnf
deleted file mode 100644
index 32482c3..0000000
--- a/grammars/c23/punctuator.bnf
+++ /dev/null
@@ -1,12 +0,0 @@
-
-# `punctuator` minus things used later (e.g. "any pp-token other than ...")
-__punctuator_base = "\." | "\+\+" | "--" | "&" | "\*" | "\+" | "-" | "~" | "!"
-| "/" | "%" | "==" | "!=" | "\^" | "\|" | "&&" | "\|\|" | "\?" | ":" | "::" | ";" | "\.\.\."
-| "=" | "\*=" | "/=" | "%=" | "\+=" | "-=" | "&=" | "\^=" | "\|="
-| "," | "##" | "%:" | "%:%:";
-
-__punctuator_left_angle_brackets = "<<" | "<" | "<=" | "<<=" | "<:" | "<%";
-__punctuator_angle_brackets = __punctuator_left_angle_brackets | ">>" | ">" | ">=" | ">>=" | ":>" | "%>" | "->";
-__punctuator_grouping = "\[" | "\]" | "\(" | "\)" | "\{" | "\}";
-
-punctuator =  __punctuator_base | __punctuator_angle_brackets | __punctuator_grouping;
\ No newline at end of file
diff --git a/src/bnf.ts b/src/bnf.ts
index 4dcd626..f1b30e2 100644
--- a/src/bnf.ts
+++ b/src/bnf.ts
@@ -35,11 +35,10 @@ const typeForGroup = {
 export function ast_to_config(ast: Node[], log: Logger = () => {}, include?: (name: string) => Node[]): config.Config {
 	const definitions: PureNodeDefinition[] = [],
 		literals: TokenDefinition[] = [],
-		ignoreLiterals: string[] = [],
-		rootNodes: string[] = [];
-
+		ignoreLiterals: string[] = [];
 	let currentNode: string,
-		groups = 0;
+		groups = 0,
+		rootNodes: string[] = [];
 
 	function processNode(node: Node, depth: number = 0) {
 		const _log = logger(log, { kind: node.kind, depth });
@@ -53,6 +52,9 @@ export function ast_to_config(ast: Node[], log: Logger = () => {}, include?: (na
 				case 'root':
 					rootNodes.push(...contents.split(/[ ,;]/));
 					break;
+				case 'override_root':
+					rootNodes = contents.split(/[ ,;]/);
+					break;
 				case 'ignore':
 					ignoreLiterals.push(...contents.split(/[ ,;]/));
 					break;