diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 00000000..0ed00b4f
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "code_to_r1cs"
+version = "0.1.0"
+authors = ["Dennis Kuhnert <mail@kyroy.com>"]
+
+[dependencies]
+regex = "0.2"
diff --git a/examples/example.code b/examples/example.code
new file mode 100644
index 00000000..f2e981ba
--- /dev/null
+++ b/examples/example.code
@@ -0,0 +1,12 @@
+// comment
+
+// comment
+
+def qeval(x):
+  // comment in function
+	y =	x**3
+  //b = x**5
+  //z = x + 3 - y + 7
+  //a = z * y + 3 * y
+  return y + x + 5
+// comment after function
diff --git a/src/ast.rs b/src/ast.rs
new file mode 100644
index 00000000..8638a095
--- /dev/null
+++ b/src/ast.rs
@@ -0,0 +1,67 @@
+use std::fmt;
+
+pub struct Prog {
+    pub id: String,
+    pub args: Vec<Parameter>,
+    pub defs: Vec<Definition>,
+}
+impl fmt::Display for Prog {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}({}):\n{}", self.id, self.args.iter().map(|x| format!("{}", x)).collect::<Vec<_>>().join(","), self.defs.iter().map(|x| format!("\t{}", x)).collect::<Vec<_>>().join("\n"))
+    }
+}
+
+pub enum Definition {
+  Return(Expression),
+  Definition(String, Expression),
+  #[allow(dead_code)]
+  IfElse(Expression, Expression, Option<Expression>),
+}
+impl fmt::Display for Definition {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Definition::Return(ref expr) => write!(f, "return {}", expr),
+            Definition::Definition(ref lhs, ref rhs) => write!(f, "{} = {}", lhs, rhs),
+            Definition::IfElse(_, _, _) => write!(f, "IfElse not implemented yet!"),
+        }
+    }
+}
+impl fmt::Debug for Definition {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self)
+    }
+}
+
+pub struct Parameter { pub id: String }
+impl fmt::Display for Parameter {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.id)
+    }
+}
+
+#[derive(Clone)]
+pub enum Expression {
+    Add(Box<Expression>, Box<Expression>),
+    Sub(Box<Expression>, Box<Expression>),
+    Mult(Box<Expression>, Box<Expression>),
+    Div(Box<Expression>, Box<Expression>),
+    Pow(Box<Expression>, Box<Expression>),
+    #[allow(dead_code)]
+    IfElse(Box<Expression>, Box<Expression>, Option<Box<Expression>>),
+    NumberLiteral(i32),
+    VariableReference(String),
+}
+impl fmt::Display for Expression {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Expression::Add(ref lhs, ref rhs) => write!(f, "{} + {}", lhs, rhs),
+            Expression::Sub(ref lhs, ref rhs) => write!(f, "{} - {}", lhs, rhs),
+            Expression::Mult(ref lhs, ref rhs) => write!(f, "{} * {}", lhs, rhs),
+            Expression::Div(ref lhs, ref rhs) => write!(f, "{} / {}", lhs, rhs),
+            Expression::Pow(ref lhs, ref rhs) => write!(f, "{}**{}", lhs, rhs),
+            Expression::IfElse(_, _, _) => write!(f, "ifelse"),
+            Expression::NumberLiteral(ref i) => write!(f, "{}", i),
+            Expression::VariableReference(ref var) => write!(f, "{}", var),
+        }
+    }
+}
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 00000000..9e78c323
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,374 @@
+#![feature(box_patterns, box_syntax)]
+
+mod ast;
+extern crate regex;
+
+use ast::*;
+use regex::Regex;
+use std::path::Path;
+use std::fs::File;
+use std::io::BufReader;
+use std::io::prelude::*;
+
+fn parse_expression_rhs(text: String) -> Expression {
+    let op_regex = Regex::new(r"^(?P<lhs>[[:alnum:]]+)(?P<op>(\*\*|[\+\-\*/]))(?P<rhs>.*)$").unwrap();
+    let variable_regex = Regex::new(r"^[[:alpha:]][[:alnum:]]*$").unwrap();
+    let number_regex = Regex::new(r"^[[:digit:]]+$").unwrap();
+    let line = text.replace(" ", "").replace("\t", "");
+    match op_regex.captures(&line) {
+        Some(x) => {
+            let lhs = if variable_regex.is_match(&x["lhs"]) {
+                Box::new(Expression::VariableReference(x["lhs"].to_string()))
+            } else if number_regex.is_match(&x["lhs"]) {
+                Box::new(Expression::NumberLiteral(x["lhs"].parse::<i32>().unwrap()))
+            } else {
+                panic!("Could not read lhs: {:?}", &x["lhs"])
+            };
+            let rhs = if variable_regex.is_match(&x["rhs"]) {
+                Box::new(Expression::VariableReference(x["rhs"].to_string()))
+            } else if number_regex.is_match(&x["rhs"])  {
+                Box::new(Expression::NumberLiteral(x["rhs"].parse::<i32>().unwrap()))
+            } else {
+                Box::new(parse_expression_rhs(x["rhs"].to_string()))
+            };
+            match &x["op"] {
+                "+" => Expression::Add(lhs, rhs),
+                "-" => Expression::Sub(lhs, rhs),
+                "*" => Expression::Mult(lhs, rhs),
+                "/" => Expression::Div(lhs, rhs),
+                "**" if number_regex.is_match(&x["rhs"]) => Expression::Pow(lhs, rhs),
+                _ => panic!("Not implemented yet")
+            }
+        },
+        None => panic!("Could not parse rhs of expression: {:?}", text),
+    }
+}
+
+fn parse_program(file: File) -> Prog {
+    let reader = BufReader::new(file);
+    let mut lines = reader.lines();
+
+    let id;
+    let args;
+    let def_regex = Regex::new(r"^def\s(?P<id>\D[a-zA-Z0-9]+)\(\s*([a-z]+)(,\s*[a-z]+)*\s*\):$").unwrap();
+    let args_regex = Regex::new(r"\(\s*(?P<args>[a-z]+(,\s*[a-z]+)*)\s*\)").unwrap();
+    loop { // search and make Prog
+        match lines.next() {
+            Some(Ok(ref x)) if x.starts_with("def") => {
+                // assert!(def_regex.is_match(x));
+                match def_regex.captures(x) {
+                    Some(x) => {
+                        // println!("def_regex {:?}", x);
+                        id = x["id"].to_string();
+                    },
+                    None => panic!("Wrong definition of function"),
+                }
+                match args_regex.captures(x) {
+                    Some(x) => {
+                        // println!("args_regex {:?}", x);
+                        args = x["args"].replace(" ", "").replace("\t", "").split(",")
+                            .map(|p| Parameter { id: p.to_string() })
+                            .collect::<Vec<_>>();
+                    },
+                    None => panic!("Wrong argument definition in function: {}", id),
+                }
+                break;
+            },
+            Some(Ok(ref x)) if x.starts_with("//") || x == "" => {},
+            None => panic!("End of file reached without function def"),
+            Some(x) => panic!("Found '{:?}' outside of function", x),
+        }
+    };
+
+    let mut defs = Vec::new();
+    let definition_regex = Regex::new(r"(?P<lhs>[a-zA-Z]+)\s*=\s*(?P<rhs>[a-zA-Z0-9\s\+\-\*/]+)\s*$").unwrap();
+    let return_regex = Regex::new(r"^return\s*(?P<rhs>[a-zA-Z0-9\s\+\-\*/]+)\s*$").unwrap();
+    loop { // make list of Definition
+        match lines.next() {
+            Some(Ok(ref x)) if x.trim().starts_with("//") || x == "" => {},
+            Some(Ok(ref line)) if line.trim().starts_with("return") => {
+                match return_regex.captures(line.trim()) {
+                    Some(x) => defs.push(Definition::Return(parse_expression_rhs(x["rhs"].to_string()))),
+                    None => panic!("Wrong return definition in function: {}", id),
+                }
+            },
+            Some(Ok(ref line)) => {
+                match definition_regex.captures(line.trim()) {
+                    Some(x) => defs.push(Definition::Definition(x["lhs"].to_string(), parse_expression_rhs(x["rhs"].to_string()))),
+                    None => panic!("Wrong expression in function '{}':\n{}", id, line),
+                }
+            },
+            None => { break },
+            Some(Err(e)) => panic!("Error while reading Definitions: {}", e),
+        }
+    }
+
+    match defs.last() {
+        Some(&Definition::Return(_)) => {},
+        Some(x) => panic!("Last definition not Return: {}", x),
+        None => panic!("Error while checking last definition"),
+    }
+    Prog { id: id, args: args, defs: defs }
+}
+
+fn flatten_rhs(defs_flattened: &mut Vec<Definition>, num_variables: &mut i32, rhs: Expression) -> Expression {
+    match rhs {
+        Expression::Pow(base, exponent) => {
+            match exponent {
+                box Expression::NumberLiteral(x) if x > 1 => {
+                    match base {
+                        box Expression::VariableReference(ref var) => {
+                            let id = if x > 2 {
+                                let tmp_expression = flatten_rhs(
+                                    defs_flattened,
+                                    num_variables,
+                                    Expression::Pow(
+                                        box Expression::VariableReference(var.to_string()),
+                                        box Expression::NumberLiteral(x - 1)
+                                    )
+                                );
+                                let new_name = format!("sym_{}", num_variables);
+                                *num_variables += 1;
+                                defs_flattened.push(Definition::Definition(new_name.to_string(), tmp_expression));
+                                new_name
+                            } else {
+                                var.to_string()
+                            };
+                            Expression::Mult(
+                                box Expression::VariableReference(id.to_string()),
+                                box Expression::VariableReference(var.to_string())
+                            )
+                        },
+                        box Expression::NumberLiteral(var) => Expression::Mult(
+                            box Expression::NumberLiteral(var),
+                            box Expression::NumberLiteral(var)
+                        ),
+                        _ => panic!("Pow only allowed for numbers and variables")
+                    }
+                }
+                _ => panic!("No Number as exponent"),
+            }
+        },
+        Expression::Add(left, right) => {
+            // TODO currently assuming that left is always Number of Variable
+            let new_right = match right {
+                box Expression::NumberLiteral(x) => Expression::NumberLiteral(x),
+                box Expression::VariableReference(ref x) => Expression::VariableReference(x.to_string()),
+                box expr => {
+                    let tmp_expression = flatten_rhs(
+                        defs_flattened,
+                        num_variables,
+                        expr
+                    );
+                    let new_name = format!("sym_{}", num_variables);
+                    *num_variables += 1;
+                    defs_flattened.push(Definition::Definition(new_name.to_string(), tmp_expression));
+                    Expression::VariableReference(new_name)
+                },
+            };
+            Expression::Add(left, Box::new(new_right))
+        },
+        Expression::Sub(left, right) => {
+            // TODO currently assuming that left is always Number of Variable
+            let new_right = match right {
+                box Expression::NumberLiteral(x) => Expression::NumberLiteral(x),
+                box Expression::VariableReference(ref x) => Expression::VariableReference(x.to_string()),
+                box expr => {
+                    let tmp_expression = flatten_rhs(
+                        defs_flattened,
+                        num_variables,
+                        expr
+                    );
+                    let new_name = format!("sym_{}", num_variables);
+                    *num_variables += 1;
+                    defs_flattened.push(Definition::Definition(new_name.to_string(), tmp_expression));
+                    Expression::VariableReference(new_name)
+                },
+            };
+            Expression::Sub(left, Box::new(new_right))
+        },
+        Expression::Mult(left, right) => {
+            // TODO currently assuming that left is always Number of Variable
+            let new_right = match right {
+                box Expression::NumberLiteral(x) => Expression::NumberLiteral(x),
+                box Expression::VariableReference(ref x) => Expression::VariableReference(x.to_string()),
+                box expr => {
+                    let tmp_expression = flatten_rhs(
+                        defs_flattened,
+                        num_variables,
+                        expr
+                    );
+                    let new_name = format!("sym_{}", num_variables);
+                    *num_variables += 1;
+                    defs_flattened.push(Definition::Definition(new_name.to_string(), tmp_expression));
+                    Expression::VariableReference(new_name)
+                },
+            };
+            Expression::Mult(left, Box::new(new_right))
+        },
+        Expression::Div(left, right) => {
+            // TODO currently assuming that left is always Number of Variable
+            let new_right = match right {
+                box Expression::NumberLiteral(x) => Expression::NumberLiteral(x),
+                box Expression::VariableReference(ref x) => Expression::VariableReference(x.to_string()),
+                box expr => {
+                    let tmp_expression = flatten_rhs(
+                        defs_flattened,
+                        num_variables,
+                        expr
+                    );
+                    let new_name = format!("sym_{}", num_variables);
+                    *num_variables += 1;
+                    defs_flattened.push(Definition::Definition(new_name.to_string(), tmp_expression));
+                    Expression::VariableReference(new_name)
+                },
+            };
+            Expression::Div(left, Box::new(new_right))
+        },
+        _ => Expression::NumberLiteral(0),
+    }
+}
+
+fn flatten_program(prog: Prog) -> Prog {
+    let mut defs_flattened = Vec::new();
+    let mut num_variables: i32 = 0;
+    for def in prog.defs {
+        match def {
+            Definition::Return(expr) => {
+                let rhs = flatten_rhs(&mut defs_flattened, &mut num_variables, expr);
+                defs_flattened.push(Definition::Return(rhs));
+            },
+            Definition::Definition(id, expr) => {
+                let rhs = flatten_rhs(&mut defs_flattened, &mut num_variables, expr);
+                defs_flattened.push(Definition::Definition(id, rhs));
+            },
+            Definition::IfElse(_, _, _) => panic!("Not implemented yet"),
+        }
+    }
+    Prog { id: prog.id, args: prog.args, defs: defs_flattened }
+}
+
+fn r1cs_expression(idx: usize, expr: Expression, variables: &mut Vec<String>, a_row: &mut Vec<(usize, i32)>, b_row: &mut Vec<(usize, i32)>, c_row: &mut Vec<(usize, i32)>) {
+    match expr {
+        Expression::Add(lhs, rhs) => {
+            c_row.push((idx, 1));
+            match (lhs, rhs) {
+                (box Expression::VariableReference(ref x1), box Expression::VariableReference(ref x2)) if x1 == x2 => {
+                    a_row.push((variables.iter().position(|r| r == x1).unwrap(), 2));
+                    b_row.push((0, 1));
+                },
+                (box Expression::VariableReference(ref x1), box Expression::VariableReference(ref x2)) /*if x1 != x2*/ => {
+                    a_row.push((variables.iter().position(|r| r == x1).unwrap(), 1));
+                    a_row.push((variables.iter().position(|r| r == x2).unwrap(), 1));
+                    b_row.push((0, 1));
+                },
+                (box Expression::NumberLiteral(num), box Expression::VariableReference(ref x)) |
+                (box Expression::VariableReference(ref x), box Expression::NumberLiteral(num)) => {
+                    a_row.push((0, num));
+                    a_row.push((variables.iter().position(|r| r == x).unwrap(), 1));
+                    b_row.push((0, 1));
+                }
+                _ => panic!("Not flattened!"),
+            }
+        },
+        Expression::Sub(lhs, rhs) => { // a - b = c --> c + b = a
+            a_row.push((idx, 1));
+            match lhs {
+                box Expression::NumberLiteral(x) => c_row.push((0, x)),
+                box Expression::VariableReference(x) => c_row.push((variables.iter().position(|r| r == &x).unwrap(), 1)),
+                _ => panic!("Not flattened!"),
+            };
+            match rhs {
+                box Expression::NumberLiteral(x) => b_row.push((0, x)),
+                box Expression::VariableReference(x) => b_row.push((variables.iter().position(|r| r == &x).unwrap(), 1)),
+                _ => panic!("Not flattened!"),
+            };
+        },
+        Expression::Mult(lhs, rhs) => {
+            c_row.push((idx, 1));
+            match lhs {
+                box Expression::NumberLiteral(x) => a_row.push((0, x)),
+                box Expression::VariableReference(x) => a_row.push((variables.iter().position(|r| r == &x).unwrap(), 1)),
+                _ => panic!("Not flattened!"),
+            };
+            match rhs {
+                box Expression::NumberLiteral(x) => b_row.push((0, x)),
+                box Expression::VariableReference(x) => b_row.push((variables.iter().position(|r| r == &x).unwrap(), 1)),
+                _ => panic!("Not flattened!"),
+            };
+        },
+        Expression::Div(lhs, rhs) => { // a / b = c --> c * b = a
+            a_row.push((idx, 1));
+            match lhs {
+                box Expression::NumberLiteral(x) => c_row.push((0, x)),
+                box Expression::VariableReference(x) => c_row.push((variables.iter().position(|r| r == &x).unwrap(), 1)),
+                _ => panic!("Not flattened!"),
+            };
+            match rhs {
+                box Expression::NumberLiteral(x) => b_row.push((0, x)),
+                box Expression::VariableReference(x) => b_row.push((variables.iter().position(|r| r == &x).unwrap(), 1)),
+                _ => panic!("Not flattened!"),
+            };
+        },
+        _ => panic!("Not implemented yet or forbidden!"),
+    }
+}
+
+fn r1cs_program(prog: Prog) {
+    let mut variables: Vec<String> = Vec::new();
+    variables.push("~one".to_string());
+    let mut a: Vec<Vec<(usize, i32)>> = Vec::new();
+    let mut b: Vec<Vec<(usize, i32)>> = Vec::new();
+    let mut c: Vec<Vec<(usize, i32)>> = Vec::new();
+    variables.extend(prog.args.iter().map(|x| format!("{}", x)));
+    for def in prog.defs {
+        let mut a_row: Vec<(usize, i32)> = Vec::new();
+        let mut b_row: Vec<(usize, i32)> = Vec::new();
+        let mut c_row: Vec<(usize, i32)> = Vec::new();
+        let idx = variables.len();
+        match def { // get all variables
+            Definition::Return(expr) => {
+                variables.push("~out".to_string());
+                r1cs_expression(idx, expr, &mut variables, &mut a_row, &mut b_row, &mut c_row);
+            },
+            Definition::Definition(id, expr) => {
+                variables.push(id);
+                r1cs_expression(idx, expr, &mut variables, &mut a_row, &mut b_row, &mut c_row);
+            },
+            Definition::IfElse(_, _, _) => panic!("Not implemented yet"),
+        }
+        a.push(a_row);
+        b.push(b_row);
+        c.push(c_row);
+    }
+    println!("variables {:?}", variables);
+    println!("A");
+    for x in a {
+        println!("{:?}", x);
+    }
+    println!("B");
+    for x in b {
+        println!("{:?}", x);
+    }
+    println!("C");
+    for x in c {
+        println!("{:?}", x);
+    }
+}
+
+fn main() {
+    let args: Vec<_> = std::env::args().collect();
+    assert!(args.len() == 2);
+
+    let path = Path::new(&args[1]);
+    let file = match File::open(&path) {
+        Ok(file) => file,
+        Err(why) => panic!("couldn't open {}: {}", path.display(), why),
+    };
+
+    let program_ast = parse_program(file);
+    println!("program:\n{}", program_ast);
+    let program_flattened = flatten_program(program_ast);
+    println!("flattened:\n{}", program_flattened);
+    r1cs_program(program_flattened);
+}