diff --git a/.gitignore b/.gitignore
index ea8c4bf..3de0729 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 /target
+dm42
\ No newline at end of file
diff --git a/Cargo.lock b/Cargo.lock
index 6400e0d..0ecb82a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,6 +2,15 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b2969dcb958b36655471fc61f7e416fa76033bdd4bfed0678d8fee1e2d07a1f0"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "anstream"
 version = "0.6.4"
@@ -108,6 +117,7 @@ version = "0.1.0"
 dependencies = [
  "anyhow",
  "clap",
+ "regex",
 ]
 
 [[package]]
@@ -116,6 +126,12 @@ version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"
 
+[[package]]
+name = "memchr"
+version = "2.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f665ee40bc4a3c5590afb1e9677db74a508659dfd71e126420da8274909a0167"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.69"
@@ -134,6 +150,35 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "regex"
+version = "1.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "380b951a9c5e80ddfd6136919eef32310721aa4aacd4889a8d39124b026ab343"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5f804c7828047e88b2d32e2d7fe5a105da8ee3264f01902f796c8e067dc2483f"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c08c74e62047bb2de4ff487b251e4a92e24f48745648451635cec7d591162d9f"
+
 [[package]]
 name = "strsim"
 version = "0.10.0"
diff --git a/Cargo.toml b/Cargo.toml
index 6115cba..2eeeccd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,3 +6,4 @@ edition = "2021"
 [dependencies]
 anyhow = "1.0.75"
 clap = { version = "4.4.7", features = ["derive"] }
+regex = "1.10.2"
diff --git a/bin/const.dm42 b/bin/const.dm42
new file mode 100644
index 0000000..2e64219
--- /dev/null
+++ b/bin/const.dm42
@@ -0,0 +1,27 @@
+// Allows using various constants
+// Flag 3 - Exit to custom menu
+
+export def const {
+    CLMENU
+    "c",   KEY 1 GTO light_speed
+    "h",   KEY 2 GTO planck_constant
+    "e",   KEY 3 GTO elementary_charge
+    "N↓A", KEY 4 GTO avogadro_constant
+    // KEY 8 GTO page_2
+    if { FS? 03 } {
+        KEY 9 GTO custom_menu
+    }
+    MENU
+    STOP
+}
+
+def custom_menu {
+    SF 27
+}
+
+// == CONSTANTS ==
+
+def light_speed { 299792458 }
+def planck_constant { 6.62607015e-34 }
+def elementary_charge { 1.602176634e-19 }
+def avogadro_constant { 6.02214076e23 }
\ No newline at end of file
diff --git a/test.dm42 b/bin/sort.dm42
similarity index 100%
rename from test.dm42
rename to bin/sort.dm42
diff --git a/out.free42 b/out.free42
index c5edce4..cec02fe 100644
--- a/out.free42
+++ b/out.free42
@@ -1,34 +1,35 @@
-LBL "sort"
-MAT?
-GTO 00
-GTO 01
+LBL "const"
+CLMENU
+"c"
+KEY 1 GTO 01
+"h"
+KEY 2 GTO 02
+"e"
+KEY 3 GTO 03
+"N↓A"
+KEY 4 GTO 04
+FS? 03
+GTO 06
+LBL 05
+MENU
+STOP
+RTN
 LBL 00
-STO "A"
-INDEX "A"
-1
-1
-STOIJ
-DROPN 2
-GTO 03
+SF 27
+RTN
+LBL 01
+299792458
+RTN
 LBL 02
-DROPN 2
-[MIN]
-DROP
-RCLIJ
-DROP
-R<>R
-DROPN 2
-I+
+6.62607015e-34
+RTN
 LBL 03
-FC? 76
-GTO 02
-DROPN 2
-RCL "A"
+1.602176634e-19
 RTN
-LBL 01
-DROPN 2
-"X is not a matrix"
-AVIEW
-STOP
-GTO 00
+LBL 04
+6.02214076e23
+RTN
+LBL 06
+KEY 9 GTO 00
+GTO 05
 RTN
diff --git a/src/codegen.rs b/src/codegen.rs
index c2af68d..b6e09c1 100644
--- a/src/codegen.rs
+++ b/src/codegen.rs
@@ -1,5 +1,7 @@
 use std::borrow::Cow;
 
+use regex::Regex;
+
 use crate::{
     ident::FreeIdent,
     misc::OrderedMap,
@@ -40,7 +42,9 @@ impl CodeGen {
     }
 
     fn get_function(&mut self, name: &str) -> &mut Function {
-        self.functions.get_mut(name).expect("Function not found")
+        self.functions
+            .get_mut(name)
+            .expect(format!("Function `{}` not found", name).as_str())
     }
 
     fn new_ident(&mut self) -> String {
@@ -102,6 +106,7 @@ fn _generate(codegen: &mut CodeGen, tokens: Vec<Token>, function: String) {
                 if body.is_empty() && else_body.is_empty() {
                     continue;
                 }
+                let is_raw = condition.is_raw();
                 gen_condition(codegen, condition, function.clone());
                 let end_label = codegen.new_ident();
 
@@ -111,7 +116,9 @@ fn _generate(codegen: &mut CodeGen, tokens: Vec<Token>, function: String) {
                     push_ins(codegen, format!("GTO {true_label}"));
 
                     let mut fun = Function::new_private(true_label.clone());
-                    fun.ins("DROPN 2".to_owned());
+                    if !is_raw {
+                        fun.ins("DROPN 2".to_owned());
+                    }
                     codegen.functions.insert(true_label.clone(), fun);
                     _generate(codegen, body, true_label.clone());
                     codegen
@@ -128,14 +135,16 @@ fn _generate(codegen: &mut CodeGen, tokens: Vec<Token>, function: String) {
                     push_ins(codegen, format!("GTO {false_label}"));
 
                     let mut fun = Function::new_private(false_label.clone());
-                    fun.ins("DROPN 2".to_owned());
+                    if !is_raw {
+                        fun.ins("DROPN 2".to_owned());
+                    }
                     codegen.functions.insert(false_label.clone(), fun);
                     _generate(codegen, else_body, false_label.clone());
                     codegen
                         .get_function(&false_label)
                         .body
                         .push(format!("GTO {end_label}"));
-                } else {
+                } else if !is_raw {
                     push_ins(codegen, "DROPN 2".to_owned());
                 }
 
@@ -164,11 +173,25 @@ fn _generate(codegen: &mut CodeGen, tokens: Vec<Token>, function: String) {
                 push_ins(codegen, format!("GTO {loop_start}"));
                 push_ins(codegen, "DROPN 2".to_owned());
             }
-            Token::Instruction(ins) => codegen.get_function(&function).body.push(ins),
+            Token::Instruction(ins) => {
+                let ins = transform_instruction(codegen, ins);
+                push_ins(codegen, ins);
+            }
         }
     }
 }
 
+fn transform_instruction(codegen: &mut CodeGen, mut ins: String) -> String {
+    // Todo, clean this up
+    for (name, func) in codegen.functions.iter() {
+        let regex = Regex::new(&format!("\\b{name}\\b")).unwrap();
+        ins = regex
+            .replace(&ins, format!("{}", func.ident()))
+            .into_owned();
+    }
+    ins
+}
+
 fn gen_condition(codegen: &mut CodeGen, condition: Condition, function: String) {
     match condition {
         Condition::Comparison { a, b, comparison } => {
diff --git a/src/token.rs b/src/token.rs
index 8f05ab9..98983c4 100644
--- a/src/token.rs
+++ b/src/token.rs
@@ -47,6 +47,12 @@ pub enum Comparison {
     Lte,
 }
 
+impl Condition {
+    pub fn is_raw(&self) -> bool {
+        matches!(self, Condition::Raw { .. })
+    }
+}
+
 impl Comparison {
     pub fn instruction(&self) -> &str {
         match self {
diff --git a/src/tokenize.rs b/src/tokenize.rs
index f7e32ae..d906fda 100644
--- a/src/tokenize.rs
+++ b/src/tokenize.rs
@@ -4,8 +4,6 @@ use anyhow::{bail, Context, Result};
 
 use crate::token::{Comparison, Condition, Token};
 
-const COMMENT_CHARS: &[char] = &['#', ';', '@'];
-
 pub struct Tokenizer {
     chars: Vec<char>,
     idx: usize,