diff --git a/config.h b/config.h
index fd81573..883a6df 100644
--- a/config.h
+++ b/config.h
@@ -10,9 +10,9 @@ const int cfg_log_facility = LOG_CRON;
 const char cfg_log_ident[] = "kairos";
 const int cfg_log_opt = LOG_PID | LOG_NDELAY;
 
-const char cfg_trie_file[] = "/home/ledoian/.kairos/trie"
-const char cfg_tasks_file[] = "/home/ledoian/.kairos/tasks"
-const char cfg_socket[] = "/tmp/kairos.sock"
+const char cfg_trie_file[] = "/home/ledoian/.kairos/trie";
+const char cfg_tasks_file[] = "/home/ledoian/.kairos/tasks";
+const char cfg_socket[] = "/tmp/kairos.sock";
 
 const int cfg_sock_maxclients = 16;
 const int cfg_var_name_max_len = 16;
diff --git a/rpn.c b/rpn.c
new file mode 100644
index 0000000..b7c2e83
--- /dev/null
+++ b/rpn.c
@@ -0,0 +1,40 @@
+/*
+ * rpn.c: evalutor of RPN formulas
+ */
+
+#include <stdint.h>
+#include <syslog.h>
+#include <stdlib.h>
+
+#include "config.h"
+#include "rpn.h"
+#include "trie.h"
+
+// Growing stack implementation
+struct grow {
+	struct trie_retval *arr;
+	int64_t elems;
+	int64_t alloc;
+}
+
+static struct grow *grow_init(void) {
+	struct grow *g = malloc(sizeof(struct grow));
+	if (g == NULL) {
+		syslog(cfg_log_facility | LOG_ERR, "rpn: Could not initialize growing array: %m");
+		return NULL;
+	}
+	g -> arr = NULL;
+	g -> elems = 0;
+	g -> alloc = 0;
+	return g;
+}
+
+static bool grow_push (int64_t val, struct grow *stack) {
+	if (stack -> alloc <= stack -> elems) {
+		stack
+	}
+}
+
+bool rpn_eval (char rpn[]) {
+	
+}
diff --git a/rpn.h b/rpn.h
new file mode 100644
index 0000000..33d286b
--- /dev/null
+++ b/rpn.h
@@ -0,0 +1,12 @@
+/*
+ * rpn.h: a header file for rpn.c
+ */
+
+#ifndef RPN_H
+#define RPN_H
+
+#include <stdbool.h>
+
+bool rpn_eval (char rpn[]);
+
+#endif
diff --git a/trie.c b/trie.c
index c4777e6..df2069d 100644
--- a/trie.c
+++ b/trie.c
@@ -5,6 +5,7 @@
 #include <string.h>
 #include <syslog.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "trie.h"
 #include "config.h"
@@ -21,11 +22,25 @@ static int indexof(char c) {
 		return 36;
 	} else {
 		// Something weird happened
-		syslog(cfg_log_facility|LOG_ERR, "trie: weird input character: %c", c);
+		syslog(cfg_log_facility|LOG_NOTICE, "trie: weird character: %c", c);
 		return -1;
 	}
 }
 
+static char charof(int i) {
+	//ASCII again
+	if (i <= 25){
+		return ('A' + i);
+	} else if (26 <= i && i <= 35) {
+		return ('0' + i - 26);
+	} else if (i == 36) {
+		return '_';
+	} else {
+		syslog(cfg_log_facility|LOG_NOTICE, "trie: weird character index: %d", i);
+		return '\0';
+	}
+}
+
 static bool trie_set_deep(char string[], int64_t val, struct trie *vertex) {
 	// Recursive function to find and set a value
 	if (string[0] = '\0') {
@@ -60,7 +75,7 @@ bool trie_set(char string[], int64_t val) {
 
 static struct trie_retval trie_lookup_deep(char string[], struct trie *vertex) {
 	if (string[0] == '\0') {
-		return (struct trie_retval) {vertex -> val, vertex -> def};
+		return (struct trie_retval) {vertex -> val, vertex -> defined};
 	} else {
 		int chld_index = indexof(string[0]);
 		if (chld_index == -1 || vertex -> children[chld_index] == NULL) {
@@ -94,12 +109,31 @@ bool trie_load(void) {
 			return false;
 		}
 		if(trie_set(name, val) == false) {
-			syslog(cfg_log_facility | LOG_WARN, "trie: setting a variable failed: %s = %d", name, val);
+			syslog(cfg_log_facility | LOG_WARNING, "trie: setting a variable failed: %s = %d", name, val);
 		}
 	}
 	return true;
 }
 
+static bool trie_dfs(char prefix[], int prefixlen, FILE *f, struct trie *vertex) {
+	if (vertex == NULL) {// Very special case;
+		return true;
+	} else {
+		bool retval = true;
+		if (vertex -> defined) {
+			prefix[prefixlen] = '\0';
+			fprintf(f, "%s %d\n", prefix, vertex -> val);
+		}
+		for (int i = 0; i<37; i++) {
+			if (vertex -> children[i] != NULL) {
+				prefix[prefixlen] = charof(i);
+				retval &= trie_dfs(prefix, prefixlen + 1, f, vertex -> children[i]);
+			}
+		}
+		return retval;
+	}
+}
+
 bool trie_save(void) {
 	FILE *f = fopen(cfg_trie_file, "w");
 	if (f == NULL) {
@@ -108,5 +142,9 @@ bool trie_save(void) {
 	}
 
 	// DFS, write every found variable into f
-	
+	char prefix[cfg_var_name_max_len +1];
+	prefix[cfg_var_name_max_len +1] = '\0';
+	int prefixlen = 0;
+
+	return trie_dfs(prefix, prefixlen, f, trie_base);
 }