diff --git a/src/main.rs b/src/main.rs
index 465aa10..37d2611 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,18 +1,33 @@
 extern crate inkwell;
 extern crate rustpython_parser;
 
-use rustpython_parser::parser;
+use rustpython_parser::{ast, parser};
 
 use inkwell::OptimizationLevel;
 use inkwell::builder::Builder;
 use inkwell::context::Context;
 use inkwell::module::Module;
 use inkwell::targets::*;
-use inkwell::passes::PassManager;
+use inkwell::types;
+use crate::inkwell::types::BasicType;
 
 use std::error::Error;
+use std::fmt;
 use std::path::Path;
 
+#[derive(Debug)]
+struct CompileError;
+
+impl fmt::Display for CompileError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "Compilation error")
+    }
+}
+
+impl Error for CompileError {}
+
+type CompileResult<T> = Result<T, CompileError>;
+
 struct CodeGen<'ctx> {
     context: &'ctx Context,
     module: Module<'ctx>,
@@ -20,26 +35,90 @@ struct CodeGen<'ctx> {
 }
 
 impl<'ctx> CodeGen<'ctx> {
-    fn compile_sum(&self) {
+    fn new(context: &'ctx Context) -> CodeGen<'ctx> {
+        CodeGen {
+            context,
+            module: context.create_module("kernel"),
+            builder: context.create_builder()
+        }
+    }
+
+    fn get_basic_type(&self, name: &str) -> CompileResult<types::BasicTypeEnum<'ctx>> {
+        match name {
+            "int32" => Ok(self.context.i32_type().into()),
+            "int64" => Ok(self.context.i64_type().into()),
+            _ => Err(CompileError)
+        }
+    }
+
+    fn compile_function_def(
+        &mut self,
+        name: &str,
+        args: &ast::Parameters,
+        body: &[ast::Statement],
+        decorator_list: &[ast::Expression],
+        returns: &Option<ast::Expression>,
+        is_async: bool,
+    ) -> CompileResult<()> {
+        if is_async {
+            return Err(CompileError)
+        }
+
+        let args_type = args.args.iter().map(|val| {
+            println!("{:?}", val.annotation);
+            if let Some(annotation) = &val.annotation {
+                if let ast::ExpressionType::Identifier { name } = &annotation.node {
+                    Ok(self.get_basic_type(&name)?)
+                } else {
+                    Err(CompileError)
+                }
+            } else {
+                Err(CompileError)
+            }
+        }).collect::<CompileResult<Vec<types::BasicTypeEnum>>>()?;
+        let return_type = match returns {
+            Some(ast::Located { location, node: ast::ExpressionType::Identifier { name }} )
+                => if name == "None" { None } else { Some(self.get_basic_type(name)?) },
+            Some(_) => return Err(CompileError),
+            None => None,
+        };
+
         let i64_type = self.context.i64_type();
-        let fn_type = i64_type.fn_type(&[i64_type.into(), i64_type.into(), i64_type.into()], false);
-        let function = self.module.add_function("sum", fn_type, None);
+        let fn_type = match return_type {
+            Some(ty) => ty.fn_type(&args_type, false),
+            None => self.context.void_type().fn_type(&args_type, false)
+        };
+
+        let function = self.module.add_function(name, fn_type, None);
         let basic_block = self.context.append_basic_block(function, "entry");
-
         self.builder.position_at_end(basic_block);
-
         let x = function.get_nth_param(0).unwrap().into_int_value();
         let y = function.get_nth_param(1).unwrap().into_int_value();
-        let z = function.get_nth_param(2).unwrap().into_int_value();
-
         let sum = self.builder.build_int_add(x, y, "sum");
-        let sum = self.builder.build_int_add(sum, z, "sum");
-
         self.builder.build_return(Some(&sum));
+        Ok(())
+    }
 
-        Target::initialize_all(&InitializationConfig::default());
+    fn compile_statement(&mut self, statement: &ast::Statement) -> CompileResult<()> {
+        use ast::StatementType::*;
+        match &statement.node {
+            FunctionDef {
+                is_async,
+                name,
+                args,
+                body,
+                decorator_list,
+                returns,
+            } => {
+                self.compile_function_def(name, args, body, decorator_list, returns, *is_async)?;
+            },
+            Pass => (),
+            _ => return Err(CompileError),
+        }
+        Ok(())
+    }
 
-        //let triple = TargetMachine::get_default_triple();
+    fn output(&self) {
         let triple = TargetTriple::create("riscv32-none-linux-gnu");
         let target = Target::from_triple(&triple)
             .expect("couldn't create target from target triple");
@@ -61,19 +140,16 @@ impl<'ctx> CodeGen<'ctx> {
     }
 }
 
-
 fn main() -> Result<(), Box<dyn Error>> {
-    let context = Context::create();
-    let module = context.create_module("sum");
-    let codegen = CodeGen {
-        context: &context,
-        module,
-        builder: context.create_builder(),
-    };
-    codegen.compile_sum();
+    Target::initialize_all(&InitializationConfig::default());
 
-    let x = parser::parse_program("def foo(x: int): print('abc')");
-    println!("{:?}", x);
+    let ast = parser::parse_program("def foo(x: int32, y: int32) -> int32: return x + y")?;
+    println!("AST: {:?}", ast);
+
+    let context = Context::create();
+    let mut codegen = CodeGen::new(&context);
+    codegen.compile_statement(&ast.statements[0])?;
+    codegen.output();
 
     Ok(())
 }