diff --git a/engine/slc.h b/engine/slc.h
index 7a6e8c8..abf8a80 100644
--- a/engine/slc.h
+++ b/engine/slc.h
@@ -200,6 +200,38 @@ typedef iores (*ioconn)(SLC_IO_OP op, const char *param);
  */
 typedef uint8_t (*coderead)();
 
+enum slc_state : uint32_t {
+	/** Before things */
+	SLC_START,
+	/** In a comment */
+	SLC_COMMENT,
+	/** In multi-line comment */
+	SLC_MULTILINE_COMMENT,
+	/** Name part of word-definition (after ':') - whitespace ends it */
+	SLC_DEF_NAME,
+	/** Variable-listing part of word-definition - endline, '(', '[' or '{' ends it */
+	SLC_DEF_VAR,
+	/** Raw body part of the word definition - these can contain local variable accesses + words (state-stack in code_stack) */
+	SLC_DEF_BODY,
+	/** ( .. ) part of the word definition - these can contain local variable accesses + words (state-stack in code_stack) */
+	SLC_DEF_PAR,
+	/** [ .. ] part of the word definition - these can contain local variable accesses + words (state-stack in code_stack) */
+	SLC_DEF_SQBR,
+	/** { .. } part of the word definition - these can contain local variable accesses + words (state-stack in code_stack) */
+	SLC_DEF_BR,
+	/** Name part of a word "call" (non-definition). */
+	SLC_WORD_NAME,
+	/** Variable part of a word "call" */
+	SLC_WORD_VAR,
+	/** ( .. ) part of a word "call" */
+	SLC_WORD_PAR,
+	/** [ .. ] part of a word "call" */
+	SLC_WORD_SQBR,
+	/** { .. } part of a word "call" */
+	SLC_WORD_BR,
+};
+typedef enum slc_state slc_state;
+
 /**
  * This function runs the main slc engine over a snippet of code.
  *
@@ -229,26 +261,33 @@ typedef uint8_t (*coderead)();
  * @param session_storage Can allocate and use arbitrary memory with this.
  * @param symbol_table The symbol table to use while processing.
  * @param code_stack The code stack (return addresses) to use.
+ * @param nesting_stack The stack used for the state-machine of the nested words.
  * @param data_stack The data stack (forth-like stack) to use.
  * @param insert_stack Used for temporarily expanding the input stream (one word level above current) with further words.
  * @param io_connector The engine uses this to open/close pipes/files and write/read them.
+ * @param singleline_comment OPTIONAL: Like "//" - the character string that makes the rest of the line being comment.
+ * @param multiline_comment_opener OPTIONAL: The character string that starts a multiline comment. Like / and * for C.
+ * @param multiline_comment_closer OPTIONAL: The character string that ends a multiline comment. Like * and / for C.
  * @param prefix The prefix added to the lookup of built-ins. Useful when you write a compiler with SLC. Defaults to "" (empty).
  * @param ender The character string that ends a word definition. Defaults to ";".
  * @param varprefix The character string that prefixes variable declarations. Defaults to "@".
  */
 static inline void slc(
-	coderead code_src,
-	session session_storage,
-	sym symbol_table,
-	stack code_stack,
-	stack data_stack,
-	stack insert_stack,
-	ioconn io_connector,
-	const char *prefix,
-	const char *ender,
-	const char *varprefix
-) {
-	// TODO
+		coderead code_src,
+		session session_storage,
+		sym symbol_table,
+		stack code_stack,
+		stack nesting_stack,
+		stack data_stack,
+		stack insert_stack,
+		ioconn io_connector,
+		const char *singleline_comment,
+		const char *multiline_comment_opener,
+		const char *multiline_comment_closer,
+		const char *prefix,
+		const char *ender,
+		const char *varprefix) {
+	slc_state main_state = SLC_START;
 }
 
 #endif /* SLC_H */