diff --git a/src/main.rs b/src/main.rs
index bc105f0..18c62be 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -22,14 +22,18 @@ fn parse_lang(lang: &str) -> Result<Vec<Instruction>, ParseError> {
         VALID_INSTRUCTION_CHARS.chars().any(|vic| vic == *c)
     });
 
-    while let Some(ins) = match_instruction(&instruction_tree_root, &mut cs) {
-        r.push(ins);
+    loop {
+        match match_instruction(&instruction_tree_root, &mut cs) {
+            Err(err) => return Err(err),
+            Ok(None) => break,
+            Ok(Some(ins)) => r.push(ins),
+        }
     }
 
     Ok(r)
 }
 
-fn match_instruction(ins_coll: &InsColl, cs: &mut dyn Iterator<Item=char>) -> Option<Instruction> {
+fn match_instruction(ins_coll: &InsColl, cs: &mut dyn Iterator<Item=char>) -> Result<Option<Instruction>, ParseError> {
     if let Some(c) = cs.next() {
         for ins in &ins_coll.inses {
             if ins.c == c {
@@ -37,15 +41,16 @@ fn match_instruction(ins_coll: &InsColl, cs: &mut dyn Iterator<Item=char>) -> Op
                     InsType::Path(ins_coll) => return match_instruction(&ins_coll, cs),
                     InsType::Node(ins) => {
                         let data = if ins.has_data() { Some(read_number(cs)) } else { None };
-                        println!("{:?} {}", ins, if let Some(n) = data { n.to_string() } else { "".to_owned() });
-                        return Some(ins.new_instruction(data));
+                        println!("{:?} {}", ins, if let Some(n) = data { n.to_string() } else { "".to_owned() }); // TODO
+                        return Ok(Some(ins.new_instruction(data)));
                     },
                 }
             }
         }
-        println!("ERROR!!!! syntax error!");
+        // println!("ERROR!!!! syntax error!");
+        return Err(ParseError::ErrorSyntax("ERROR!!!! syntax error!".into()));
     }
-    None
+    Ok(None)
 }
 
 fn read_number(cs: &mut dyn Iterator<Item=char>) -> isize {