diff --git a/engine/slc.h b/engine/slc.h
index b75bc20..5a4f96a 100644
--- a/engine/slc.h
+++ b/engine/slc.h
@@ -5,6 +5,9 @@
 #include<string.h> // memcpy, strlen..
 #include<stddef.h> // NULL
 
+/* Define this if you want to debug the engine doing its thing */
+/* #define SLC_DEBUG */
+
 /* Session offset type - defaults to 64 bit because of union types enable storage for it often, but you can override */
 #ifndef SLOFFS_T
 #define SLOFFS_T uint64_t
@@ -268,11 +271,30 @@ static inline slc_state slc_comment_statechange_in(
 		char c,
 		const char *singleline_comment,
 		const char *multiline_comment_opener,
-		int singleline_comment_len,
-		int multiline_comment_len,
 		int *comment_i,
 		int *multiline_i){
-	// FIXME: Implement
+
+	char s = singleline_comment[*comment_i];
+	char m = multiline_comment_opener[*multiline_i];
+
+	/* Check if we have finished processing */
+	if(s == 0) return SLC_COMMENT;
+	if(m == 0) return SLC_MULTILINE_COMMENT;
+
+	/* Single-line comment progress */
+	if(c == s) {
+		++(*comment_i);
+	} else {
+		*comment_i = 0;
+	}
+
+	/* Multi-line comment progress */
+	if(c == m) {
+		++(*multiline_i);
+	} else {
+		*multiline_i = 0;
+	}
+
 	return current_state;
 }
 
@@ -351,8 +373,6 @@ static inline void slc(
 		const char *varprefix) {
 
 	slc_state state = SLC_START;
-	int singleline_comment_len = strlen(singleline_comment);
-	int multiline_comment_opener_len = strlen(multiline_comment_opener);
 
 	// TODO: Count line numbers
 	// TODO: Handle/count indentation for better error messages
@@ -374,8 +394,6 @@ static inline void slc(
 						c,
 						singleline_comment,
 						multiline_comment_opener, 
-						singleline_comment_len,
-						multiline_comment_opener_len,
 						&comment_i,
 						&multiline_i);