diff --git a/crsn/src/asm/instr/flatten.rs b/crsn/src/asm/instr/flatten.rs
index da6436f..3fc3bab 100644
--- a/crsn/src/asm/instr/flatten.rs
+++ b/crsn/src/asm/instr/flatten.rs
@@ -9,11 +9,11 @@ use crate::builtin::defs::BuiltinOp;
 
 /// A trait for something that can turn into multiple instructions
 pub trait Flatten {
-    fn flatten(self, label_num: &AtomicU32) -> Result<Vec<Op>, CrsnError>;
+    fn flatten(self: Box<Self>, label_num: &AtomicU32) -> Result<Vec<Op>, CrsnError>;
 }
 
 impl Flatten for Instr {
-    fn flatten(self, label_num: &AtomicU32) -> Result<Vec<Op>, CrsnError> {
+    fn flatten(self: Box<Self>, label_num: &AtomicU32) -> Result<Vec<Op>, CrsnError> {
         let mut ops = vec![self.op];
 
         if let Some(branches) = self.branches {
@@ -31,10 +31,7 @@ impl Flatten for Instr {
                     Label::unique(label_num)
                 };
                 ops.push(BuiltinOp::JumpIf(!cond, next_lbl.clone()).into());
-
-                for branch_instr in branch {
-                    ops.extend(branch_instr.flatten(label_num)?);
-                }
+                ops.extend(branch.flatten(label_num)?);
 
                 if cnt != branch_count - 1 {
                     ops.push(BuiltinOp::Jump(end_lbl.clone()).into());
@@ -48,15 +45,23 @@ impl Flatten for Instr {
     }
 }
 
+impl Flatten for Vec<Box<dyn Flatten>> {
+    fn flatten(self: Box<Self>, label_num: &AtomicU32) -> Result<Vec<Op>, CrsnError> {
+        let mut ops = vec![];
+        for item in self.into_iter() {
+            ops.extend(item.flatten(label_num)?);
+        }
+        Ok(ops)
+    }
+}
+
 impl Flatten for Routine {
-    fn flatten(self, label_num: &AtomicU32) -> Result<Vec<Op>, CrsnError> {
+    fn flatten(self: Box<Self>, label_num: &AtomicU32) -> Result<Vec<Op>, CrsnError> {
         let mut ops = vec![
             BuiltinOp::Routine(self.name.clone()).into(),
         ];
 
-        for instr in self.body {
-            ops.extend(instr.flatten(label_num)?);
-        }
+        ops.extend(self.body.flatten(label_num)?);
 
         ops.push(BuiltinOp::Barrier(Some(format!("Routine \"{}\" overrun", self.name).into())).into());
 
diff --git a/crsn/src/asm/instr/mod.rs b/crsn/src/asm/instr/mod.rs
index f1f7ead..94f25a5 100644
--- a/crsn/src/asm/instr/mod.rs
+++ b/crsn/src/asm/instr/mod.rs
@@ -9,15 +9,13 @@ pub mod cond;
 mod flatten;
 
 /// A higher-level instruction
-#[derive(Debug)]
 pub struct Instr {
     pub op: Op,
-    pub branches: Option<Vec<(Cond, Vec<Instr>)>>,
+    pub branches: Option<Vec<(Cond, Box<dyn Flatten>)>>,
 }
 
 /// A routine
 pub struct Routine {
     pub name: RoutineName,
-    pub body: Vec<Instr>,
+    pub body: Box<dyn Flatten>,
 }
-
diff --git a/crsn/src/asm/parse/arg_parser.rs b/crsn/src/asm/parse/arg_parser.rs
index cc14fa2..111b7e1 100644
--- a/crsn/src/asm/parse/arg_parser.rs
+++ b/crsn/src/asm/parse/arg_parser.rs
@@ -5,21 +5,22 @@ use crate::asm::parse::parse_data::{parse_rd, parse_wr};
 use crate::asm::parse::sexp_expect::expect_string_atom;
 
 /// Utility for argument parsing
-pub struct ArgParser {
+pub struct TokenParser {
     orig_len: usize,
     args: Vec<Sexp>,
 }
 
-impl IntoIterator for ArgParser {
+impl IntoIterator for TokenParser {
     type Item = Sexp;
     type IntoIter = std::vec::IntoIter<Sexp>;
 
-    fn into_iter(self) -> Self::IntoIter {
+    fn into_iter(mut self) -> Self::IntoIter {
+        self.args.reverse();
         self.args.into_iter()
     }
 }
 
-impl ArgParser {
+impl TokenParser {
     /// Create a new argument parser
     pub fn new(mut args: Vec<Sexp>) -> Self {
         args.reverse();
diff --git a/crsn/src/asm/parse/mod.rs b/crsn/src/asm/parse/mod.rs
index fe08f4e..0e471e1 100644
--- a/crsn/src/asm/parse/mod.rs
+++ b/crsn/src/asm/parse/mod.rs
@@ -1,7 +1,6 @@
-use std::sync::atomic::AtomicU32;
+use std::sync::atomic::{AtomicU32, AtomicU64};
 
 pub use parse_instr::parse_instructions;
-use parse_routines::parse_routines;
 
 use crate::asm::error::CrsnError;
 use crate::asm::instr::{Flatten, Op, Routine};
@@ -11,22 +10,15 @@ use crate::module::CrsnExtension;
 mod parse_cond;
 mod parse_instr;
 pub mod parse_data;
-mod parse_routines;
 pub mod sexp_expect;
 mod parse_op;
 
 pub mod arg_parser;
 
 pub fn parse(source: &str, parsers: &[Box<dyn CrsnExtension>]) -> Result<Vec<Op>, CrsnError> {
-    let root = sexp::parse(source)?;
+    let items = expect_list(Some(sexp::parse(source)?), true)?;
 
-    let subs: Vec<Routine> = parse_routines(expect_list(Some(root), true)?, parsers)?;
-
-    let mut combined = vec![];
     let label_num = AtomicU32::new(0);
-    for sub in subs {
-        combined.extend(sub.flatten(&label_num)?);
-    }
-
-    Ok(combined)
+    parse_instructions(items.into_iter(), parsers)?
+        .flatten(&label_num)
 }
diff --git a/crsn/src/asm/parse/parse_cond.rs b/crsn/src/asm/parse/parse_cond.rs
index 177aa80..5089c45 100644
--- a/crsn/src/asm/parse/parse_cond.rs
+++ b/crsn/src/asm/parse/parse_cond.rs
@@ -1,13 +1,13 @@
 use sexp::Sexp;
 
 use crate::asm::error::CrsnError;
-use crate::asm::instr::{Cond, cond, Instr};
+use crate::asm::instr::{Cond, cond, Instr, Flatten};
 use crate::asm::parse::parse_instr::parse_instructions;
 use crate::asm::parse::sexp_expect::{expect_list, expect_string_atom};
 use crate::asm::patches::TryRemove;
 use crate::module::CrsnExtension;
 
-pub fn parse_cond_branch(tok: Sexp, parsers: &[Box<dyn CrsnExtension>]) -> Result<(Cond, Vec<Instr>), CrsnError> {
+pub fn parse_cond_branch(tok: Sexp, parsers: &[Box<dyn CrsnExtension>]) -> Result<(Cond, Box<dyn Flatten>), CrsnError> {
     let mut list = expect_list(Some(tok), false)?;
     let kw = expect_string_atom(list.try_remove(0))?;
 
@@ -15,6 +15,6 @@ pub fn parse_cond_branch(tok: Sexp, parsers: &[Box<dyn CrsnExtension>]) -> Resul
         return Err(CrsnError::Parse(format!("Condition must end with '?': {}", kw).into()));
     }
 
-    Ok((cond::parse_cond(&kw)?, parse_instructions(list, parsers)?))
+    Ok((cond::parse_cond(&kw)?, parse_instructions(list.into_iter(), parsers)?))
 }
 
diff --git a/crsn/src/asm/parse/parse_instr.rs b/crsn/src/asm/parse/parse_instr.rs
index 0025de7..8e9e184 100644
--- a/crsn/src/asm/parse/parse_instr.rs
+++ b/crsn/src/asm/parse/parse_instr.rs
@@ -1,24 +1,49 @@
 use sexp::Sexp;
 
 use crate::asm::error::CrsnError;
-use crate::asm::instr::Instr;
-use crate::asm::parse::arg_parser::ArgParser;
+use crate::asm::instr::{Instr, Flatten, Routine};
+use crate::asm::parse::arg_parser::TokenParser;
 use crate::asm::parse::parse_cond::parse_cond_branch;
 use crate::asm::parse::sexp_expect::{expect_list, expect_string_atom};
 use crate::asm::patches::SexpIsA;
-use crate::module::CrsnExtension;
+use crate::module::{CrsnExtension, ParseRes};
 
 use super::parse_op::parse_op;
+use crate::asm::data::literal::RoutineName;
 
-pub fn parse_instructions(instrs: Vec<Sexp>, parsers: &[Box<dyn CrsnExtension>]) -> Result<Vec<Instr>, CrsnError> {
+pub fn parse_instructions(items: impl Iterator<Item=Sexp>, parsers: &[Box<dyn CrsnExtension>]) -> Result<Box<dyn Flatten>, CrsnError> {
     let mut parsed = vec![];
-    for expr in instrs {
+    for expr in items {
         let tokens = expect_list(Some(expr), false)?;
 
         let mut toki = tokens.into_iter();
         let name = expect_string_atom(toki.next())?;
 
-        let arg_tokens = ArgParser::new(toki.clone().take_while(|e| e.is_atom()).collect());
+        if name == "proc" {
+            parsed.push(parse_routine(toki, parsers)?);
+            continue;
+        }
+
+        let mut token_parser = TokenParser::new(toki.collect());
+        for p in parsers {
+            token_parser = match p.parse_syntax(&name, token_parser, parsers) {
+                Ok(ParseRes::Parsed(op)) => return Ok(op),
+                Ok(ParseRes::Unknown(to_reuse)) => {
+                    if to_reuse.parsing_started() {
+                        panic!("Module \"{}\" started parsing syntax, but returned Unknown!", p.name());
+                    }
+                    to_reuse
+                }
+                Err(err) => {
+                    return Err(err);
+                }
+            }
+        }
+
+        // Get back the original iterator
+        let toki = token_parser.into_iter();
+
+        let arg_tokens = TokenParser::new(toki.clone().take_while(|e| e.is_atom()).collect());
         let branch_tokens = toki
             .skip_while(|e| e.is_atom())
             .take_while(|e| e.is_list());
@@ -35,11 +60,25 @@ pub fn parse_instructions(instrs: Vec<Sexp>, parsers: &[Box<dyn CrsnExtension>])
             }
         };
 
-        parsed.push(Instr {
+        parsed.push(Box::new(Instr {
             op: parse_op(name.as_str(), arg_tokens, parsers)?,
             branches,
-        });
+        }));
     }
-    Ok(parsed)
+    Ok(Box::new(parsed))
 }
 
+fn parse_routine(mut toki : impl Iterator<Item=Sexp> + Clone, parsers: &[Box<dyn CrsnExtension>]) ->  Result<Box<dyn Flatten>, CrsnError> {
+    let name = expect_string_atom(toki.next())?;
+
+    let arg_tokens = TokenParser::new(toki.clone().take_while(|e| e.is_atom()).collect());
+
+    // TODO parse arg tokens
+
+    let body = parse_instructions(toki, parsers)?;
+
+    return Ok(Box::new(Routine {
+        name: RoutineName(name),
+        body
+    }))
+}
diff --git a/crsn/src/asm/parse/parse_op.rs b/crsn/src/asm/parse/parse_op.rs
index 3b0c07d..7b64b80 100644
--- a/crsn/src/asm/parse/parse_op.rs
+++ b/crsn/src/asm/parse/parse_op.rs
@@ -1,17 +1,17 @@
 use crate::asm::error::CrsnError;
 use crate::asm::instr::Op;
-use crate::asm::parse::arg_parser::ArgParser;
+use crate::asm::parse::arg_parser::TokenParser;
 use crate::builtin::parse::BuiltinOps;
-use crate::module::{CrsnExtension, ParseOpRes};
+use crate::module::{CrsnExtension, ParseRes};
 
-pub fn parse_op(keyword: &str, mut arg_tokens: ArgParser, parsers: &[Box<dyn CrsnExtension>]) -> Result<Op, CrsnError> {
+pub fn parse_op(keyword: &str, mut arg_tokens: TokenParser, parsers: &[Box<dyn CrsnExtension>]) -> Result<Op, CrsnError> {
     // Include built-in instructions
     let builtins = [BuiltinOps::new()];
 
     for p in builtins.iter().chain(parsers) {
         arg_tokens = match p.parse_op(keyword, arg_tokens) {
-            Ok(ParseOpRes::Parsed(op)) => return Ok(op),
-            Ok(ParseOpRes::Unknown(to_reuse)) => {
+            Ok(ParseRes::Parsed(op)) => return Ok(op),
+            Ok(ParseRes::Unknown(to_reuse)) => {
                 if to_reuse.parsing_started() {
                     panic!("Module \"{}\" started parsing {}, but returned Unknown!", p.name(), keyword);
                 }
diff --git a/crsn/src/asm/parse/parse_routines.rs b/crsn/src/asm/parse/parse_routines.rs
deleted file mode 100644
index 081f169..0000000
--- a/crsn/src/asm/parse/parse_routines.rs
+++ /dev/null
@@ -1,23 +0,0 @@
-use sexp::Sexp;
-
-use crate::asm::data::literal::RoutineName;
-use crate::asm::error::CrsnError;
-use crate::asm::instr::Routine;
-use crate::asm::parse::parse_instr::parse_instructions;
-use crate::asm::parse::sexp_expect::{expect_list, expect_string_atom};
-use crate::asm::patches::TryRemove;
-use crate::module::CrsnExtension;
-
-pub fn parse_routines(routines: Vec<Sexp>, parsers: &[Box<dyn CrsnExtension>]) -> Result<Vec<Routine>, CrsnError> {
-    let mut parsed = vec![];
-    for rt in routines {
-        let mut def = expect_list(Some(rt), false)?;
-        let name = expect_string_atom(def.try_remove(0))?;
-        let body = parse_instructions(def, parsers)?;
-        parsed.push(Routine {
-            name: RoutineName(name),
-            body,
-        })
-    }
-    Ok(parsed)
-}
diff --git a/crsn/src/builtin/parse.rs b/crsn/src/builtin/parse.rs
index bbae512..dd1d40b 100644
--- a/crsn/src/builtin/parse.rs
+++ b/crsn/src/builtin/parse.rs
@@ -4,11 +4,11 @@ use crate::asm::data::literal::{Label, RoutineName};
 use crate::asm::error::CrsnError;
 use crate::asm::instr::cond::parse_cond;
 use crate::asm::instr::Op;
-use crate::asm::parse::arg_parser::ArgParser;
+use crate::asm::parse::arg_parser::TokenParser;
 use crate::asm::parse::parse_data::{parse_label, parse_rd};
 use crate::asm::parse::sexp_expect::expect_string_atom;
 use crate::builtin::defs::BuiltinOp;
-use crate::module::{CrsnExtension, ParseOpRes};
+use crate::module::{CrsnExtension, ParseRes};
 
 #[derive(Debug, Clone)]
 pub struct BuiltinOps {
@@ -28,8 +28,8 @@ impl CrsnExtension for BuiltinOps {
         "builtin"
     }
 
-    fn parse_op(&self, keyword: &str, mut args: ArgParser) -> Result<ParseOpRes<Op>, CrsnError> {
-        Ok(ParseOpRes::Parsed(Op::BuiltIn(match keyword {
+    fn parse_op(&self, keyword: &str, mut args: TokenParser) -> Result<ParseRes<Op>, CrsnError> {
+        Ok(ParseRes::Parsed(Op::BuiltIn(match keyword {
             "nop" => {
                 BuiltinOp::Nop
             }
@@ -142,10 +142,10 @@ impl CrsnExtension for BuiltinOps {
                         let label = Label::Named(label.to_string());
                         BuiltinOp::FarLabel(label)
                     } else {
-                        return Ok(ParseOpRes::Unknown(args));
+                        return Ok(ParseRes::Unknown(args));
                     }
                 } else {
-                    return Ok(ParseOpRes::Unknown(args));
+                    return Ok(ParseRes::Unknown(args));
                 }
             }
 
@@ -154,7 +154,7 @@ impl CrsnExtension for BuiltinOps {
                     let label = Label::Named(label.to_string());
                     BuiltinOp::Label(label)
                 } else {
-                    return Ok(ParseOpRes::Unknown(args));
+                    return Ok(ParseRes::Unknown(args));
                 }
             }
         })))
diff --git a/crsn/src/module/mod.rs b/crsn/src/module/mod.rs
index cb5f51a..473c1b8 100644
--- a/crsn/src/module/mod.rs
+++ b/crsn/src/module/mod.rs
@@ -1,3 +1,5 @@
+#![allow(unused_variables)]
+
 use std::fmt::Debug;
 
 pub use eval_res::EvalRes;
@@ -5,8 +7,8 @@ pub use eval_res::EvalRes;
 use crate::asm::data::literal::Value;
 use crate::asm::data::Mask;
 use crate::asm::error::CrsnError;
-use crate::asm::instr::Op;
-use crate::asm::parse::arg_parser::ArgParser;
+use crate::asm::instr::{Op, Flatten};
+use crate::asm::parse::arg_parser::TokenParser;
 use crate::runtime::fault::Fault;
 use crate::runtime::run_thread::state::RunState;
 use crate::runtime::run_thread::ThreadInfo;
@@ -14,14 +16,14 @@ use crate::runtime::run_thread::ThreadInfo;
 mod eval_res;
 
 /// Result type returned from the op parser. This is the Ok variant of a Result.
-pub enum ParseOpRes<T> {
+pub enum ParseRes<T> {
     /// Parsing successful.
     Parsed(T),
     /// Instruction not recognized, but there was no error.
-    Unknown(ArgParser),
+    Unknown(TokenParser),
 }
 
-impl ParseOpRes<Op> {
+impl ParseRes<Op> {
     /// Helper to construct an extension op
     pub fn ext(op: impl OpTrait) -> Self {
         Self::Parsed(Op::Ext(Box::new(op)))
@@ -41,36 +43,35 @@ pub trait CrsnExtension: Debug + Send + Sync + 'static {
     /// the argument list and either return Ok or Err.
     ///
     /// If the instruction keyword is not recognized, return Unknown with the unchanged argument list.
-    fn parse_op(&self, keyword: &str, arg_tokens: ArgParser) -> Result<ParseOpRes<Op>, CrsnError>;
+    fn parse_op(&self, keyword: &str, arg_tokens: TokenParser) -> Result<ParseRes<Op>, CrsnError>;
+
+    /// Parse a generic S-expression (non-op)
+    fn parse_syntax(&self, keyword: &str, tokens: TokenParser, parsers: &[Box<dyn CrsnExtension>])
+        -> Result<ParseRes<Box<dyn Flatten>>, CrsnError>
+    {
+        Ok(ParseRes::Unknown(tokens))
+    }
 
     /// Drop an object referenced by a handle
-    fn drop_obj(&self,
-                #[allow(unused)] ti: &ThreadInfo,
-                #[allow(unused)] state: &mut RunState,
-                #[allow(unused)] handle: Value) -> Result<Option<()>, Fault>
+    fn drop_obj(&self, ti: &ThreadInfo, state: &mut RunState, handle: Value)
+        -> Result<Option<()>, Fault>
     {
         // Default impl - we do not support dropping this object
         Ok(None)
     }
 
     /// Run-time method called to read an object (using the object handle syntax)
-    fn read_obj(&self,
-                #[allow(unused)] ti: &ThreadInfo,
-                #[allow(unused)] state: &mut RunState,
-                #[allow(unused)] handle: Value,
-                #[allow(unused)] mask: Mask,
-    ) -> Result<Option<Value>, Fault> {
+    fn read_obj(&self, ti: &ThreadInfo, state: &mut RunState, handle: Value, _mask: Mask)
+        -> Result<Option<Value>, Fault>
+    {
         // Default impl - we do not support reading this object
         Ok(None)
     }
 
     /// Run-time method called to write an object (using the object handle syntax)
-    fn write_obj(&self,
-                 #[allow(unused)] ti: &ThreadInfo,
-                 #[allow(unused)] state: &mut RunState,
-                 #[allow(unused)] handle: Value,
-                 #[allow(unused)] mask: Mask,
-    ) -> Result<Option<()>, Fault> {
+    fn write_obj(&self, ti: &ThreadInfo, state: &mut RunState, handle: Value, mask: Mask)
+        -> Result<Option<()>, Fault>
+    {
         // Default impl - we do not support writing this object
         Ok(None)
     }
diff --git a/crsn_arith/src/lib.rs b/crsn_arith/src/lib.rs
index e3b2824..6f2eb58 100644
--- a/crsn_arith/src/lib.rs
+++ b/crsn_arith/src/lib.rs
@@ -1,7 +1,7 @@
 use crsn::asm::error::CrsnError;
 use crsn::asm::instr::Op;
-use crsn::asm::parse::arg_parser::ArgParser;
-use crsn::module::{CrsnExtension, ParseOpRes};
+use crsn::asm::parse::arg_parser::TokenParser;
+use crsn::module::{CrsnExtension, ParseRes};
 
 mod defs;
 mod parse;
@@ -21,7 +21,7 @@ impl CrsnExtension for ArithOps {
         "arith"
     }
 
-    fn parse_op(&self, keyword: &str, args: ArgParser) -> Result<ParseOpRes<Op>, CrsnError> {
+    fn parse_op(&self, keyword: &str, args: TokenParser) -> Result<ParseRes<Op>, CrsnError> {
         parse::parse(keyword, args)
     }
 }
diff --git a/crsn_arith/src/parse.rs b/crsn_arith/src/parse.rs
index 4912393..5aae72f 100644
--- a/crsn_arith/src/parse.rs
+++ b/crsn_arith/src/parse.rs
@@ -1,13 +1,13 @@
 use crsn::asm::data::{Rd, Wr};
 use crsn::asm::error::CrsnError;
 use crsn::asm::instr::Op;
-use crsn::asm::parse::arg_parser::ArgParser;
-use crsn::module::ParseOpRes;
+use crsn::asm::parse::arg_parser::TokenParser;
+use crsn::module::ParseRes;
 
 use crate::defs::ArithOp;
 
-pub(crate) fn parse(keyword: &str, mut args: ArgParser) -> Result<ParseOpRes<Op>, CrsnError> {
-    Ok(ParseOpRes::ext(match keyword {
+pub(crate) fn parse(keyword: &str, mut args: TokenParser) -> Result<ParseRes<Op>, CrsnError> {
+    Ok(ParseRes::ext(match keyword {
         "cmp" => {
             ArithOp::Compare {
                 a: args.next_rd()?,
@@ -430,7 +430,7 @@ pub(crate) fn parse(keyword: &str, mut args: ArgParser) -> Result<ParseOpRes<Op>
         }
 
         _other => {
-            return Ok(ParseOpRes::Unknown(args));
+            return Ok(ParseRes::Unknown(args));
         }
     }))
 }
diff --git a/crsn_screen/src/lib.rs b/crsn_screen/src/lib.rs
index 39d07fc..af8d674 100644
--- a/crsn_screen/src/lib.rs
+++ b/crsn_screen/src/lib.rs
@@ -3,8 +3,8 @@ extern crate log;
 
 use crsn::asm::error::CrsnError;
 use crsn::asm::instr::Op;
-use crsn::asm::parse::arg_parser::ArgParser;
-use crsn::module::{CrsnExtension, ParseOpRes};
+use crsn::asm::parse::arg_parser::TokenParser;
+use crsn::module::{CrsnExtension, ParseRes};
 
 mod defs;
 mod parse;
@@ -24,7 +24,7 @@ impl CrsnExtension for ScreenOps {
         "screen"
     }
 
-    fn parse_op(&self, keyword: &str, args: ArgParser) -> Result<ParseOpRes<Op>, CrsnError> {
+    fn parse_op(&self, keyword: &str, args: TokenParser) -> Result<ParseRes<Op>, CrsnError> {
         parse::parse(keyword, args)
     }
 }
diff --git a/crsn_screen/src/parse.rs b/crsn_screen/src/parse.rs
index 6b896fb..a6fcaa1 100644
--- a/crsn_screen/src/parse.rs
+++ b/crsn_screen/src/parse.rs
@@ -1,13 +1,13 @@
 use crsn::asm::data::Rd;
 use crsn::asm::error::CrsnError;
 use crsn::asm::instr::Op;
-use crsn::asm::parse::arg_parser::ArgParser;
-use crsn::module::ParseOpRes;
+use crsn::asm::parse::arg_parser::TokenParser;
+use crsn::module::ParseRes;
 
 use crate::defs::ScreenOp;
 
-pub(crate) fn parse(keyword: &str, mut args: ArgParser) -> Result<ParseOpRes<Op>, CrsnError> {
-    Ok(ParseOpRes::ext(match keyword {
+pub(crate) fn parse(keyword: &str, mut args: TokenParser) -> Result<ParseRes<Op>, CrsnError> {
+    Ok(ParseRes::ext(match keyword {
         "sc-init" => {
             ScreenOp::ScreenInit {
                 width: args.next_rd()?,
@@ -41,7 +41,7 @@ pub(crate) fn parse(keyword: &str, mut args: ArgParser) -> Result<ParseOpRes<Op>
         }
 
         _other => {
-            return Ok(ParseOpRes::Unknown(args));
+            return Ok(ParseRes::Unknown(args));
         }
     }))
 }
diff --git a/crsn_stacks/src/lib.rs b/crsn_stacks/src/lib.rs
index 828739f..da6a728 100644
--- a/crsn_stacks/src/lib.rs
+++ b/crsn_stacks/src/lib.rs
@@ -1,8 +1,8 @@
 use crsn::asm::data::literal::Value;
 use crsn::asm::error::CrsnError;
 use crsn::asm::instr::Op;
-use crsn::asm::parse::arg_parser::ArgParser;
-use crsn::module::{CrsnExtension, ParseOpRes};
+use crsn::asm::parse::arg_parser::TokenParser;
+use crsn::module::{CrsnExtension, ParseRes};
 use crsn::runtime::fault::Fault;
 use crsn::runtime::run_thread::{RunState, ThreadInfo};
 
@@ -24,7 +24,7 @@ impl CrsnExtension for StackOps {
         "stacks"
     }
 
-    fn parse_op(&self, keyword: &str, args: ArgParser) -> Result<ParseOpRes<Op>, CrsnError> {
+    fn parse_op(&self, keyword: &str, args: TokenParser) -> Result<ParseRes<Op>, CrsnError> {
         parse::parse(keyword, args)
     }
 
diff --git a/crsn_stacks/src/parse.rs b/crsn_stacks/src/parse.rs
index b5368fc..f9192ff 100644
--- a/crsn_stacks/src/parse.rs
+++ b/crsn_stacks/src/parse.rs
@@ -1,12 +1,12 @@
 use crsn::asm::error::CrsnError;
 use crsn::asm::instr::Op;
-use crsn::asm::parse::arg_parser::ArgParser;
-use crsn::module::ParseOpRes;
+use crsn::asm::parse::arg_parser::TokenParser;
+use crsn::module::ParseRes;
 
 use crate::defs::StackOp;
 
-pub(crate) fn parse(keyword: &str, mut args: ArgParser) -> Result<ParseOpRes<Op>, CrsnError> {
-    Ok(ParseOpRes::ext(match keyword {
+pub(crate) fn parse(keyword: &str, mut args: TokenParser) -> Result<ParseRes<Op>, CrsnError> {
+    Ok(ParseRes::ext(match keyword {
         "stack" => {
             StackOp::NewStack {
                 dst: args.next_wr()?,
@@ -28,7 +28,7 @@ pub(crate) fn parse(keyword: &str, mut args: ArgParser) -> Result<ParseOpRes<Op>
         }
 
         _other => {
-            return Ok(ParseOpRes::Unknown(args));
+            return Ok(ParseRes::Unknown(args));
         }
     }))
 }
diff --git a/examples/factorial.csn b/examples/factorial.csn
index 11e17bc..e4ebf93 100644
--- a/examples/factorial.csn
+++ b/examples/factorial.csn
@@ -1,10 +1,10 @@
 (
-    (main
+    (proc main
         (call fac 5)
         (ld r0 res0)
         (halt)
     )
-    (fac
+    (proc fac
         (cmp arg0 2
             (eq? (ret 2)))
         (sub r0 arg0 1)
diff --git a/examples/screen_bounce.csn b/examples/screen_bounce.csn
index 068081c..cea432e 100644
--- a/examples/screen_bounce.csn
+++ b/examples/screen_bounce.csn
@@ -1,10 +1,10 @@
 ; Set log level to "info" or above for the best results!
 
 (
-    (main
+    (proc main
         (sc-init 800 600)
-        (sc-opt 1 0) ; auto blit
-        (sc-opt 2 60) ; frame rate
+        (sc-opt 1 1) ; auto blit
+        (sc-opt 2 25) ; frame rate
 
         (ld r0 5) ; x
         (ld r1 0) ; y
@@ -15,16 +15,12 @@
         (ld r5 0x3300ff)
 
         (:loop)
-        (add r5 0x000001)
-        (and r5 0xffffff)
-        (sc-px r0 r1 r5)
-        (add r0 r2)
-        (add r1 r3)
-        (cmp r0 799 (eq? (ld r2 -1)))
-        (cmp r0 0 (eq? (ld r2 1)))
-        (cmp r1 599 (eq? (ld r3 -1)))
-        (cmp r1 0 (eq? (ld r3 1)))
-        (sc-blit 0)
+            (add r5 0x000001)
+            (sc-px r0 r1 r5)
+            (add r0 r2)
+            (add r1 r3)
+            (cmp r0 799 (eq? (ld r2 -1)) (ne? (cmp r0 0 (eq? (ld r2 1)))))
+            (cmp r1 599 (eq? (ld r3 -1)) (ne? (cmp r1 0 (eq? (ld r3 1)))))
         (j :loop)
     )
 )