diff --git a/design.md b/design.md
index 59a7a0b..c5d71a9 100644
--- a/design.md
+++ b/design.md
@@ -6,9 +6,8 @@ Playground for language design dessisions
 
 ```tt
 fn hi(arg1: i32, arg2: i32) = {
-    arg1 + 
+    arg1 + arg2
     // Hi
-        arg2
 };
 
 fn main() = {
diff --git a/tast/tast.go b/tast/tast.go
index ff7f125..1902f13 100644
--- a/tast/tast.go
+++ b/tast/tast.go
@@ -252,3 +252,35 @@ func (ae *AssignmentExpression) Tok() token.Token     { return ae.Token }
 func (ae *AssignmentExpression) String() string {
 	return fmt.Sprintf("%s = %s", ae.Lhs.String(), ae.Rhs.String())
 }
+
+// identifier ( expressions... )
+type FunctionCall struct {
+	Token      token.Token // The identifier
+	Identifier string
+	Arguments  []Expression
+	ReturnType types.Type
+}
+
+var _ Expression = &FunctionCall{}
+
+func (fc *FunctionCall) expressionNode()      {}
+func (fc *FunctionCall) Type() types.Type     { return fc.ReturnType }
+func (fc *FunctionCall) TokenLiteral() string { return fc.Token.Literal }
+func (fc *FunctionCall) Tok() token.Token     { return fc.Token }
+func (fc *FunctionCall) String() string {
+	b := strings.Builder{}
+
+	b.WriteString(fc.Identifier)
+	b.WriteRune('(')
+
+	for i, arg := range fc.Arguments {
+		b.WriteString(arg.String())
+		if i < (len(fc.Arguments) - 1) {
+			b.WriteRune(',')
+		}
+	}
+
+	b.WriteRune(')')
+
+	return b.String()
+}
diff --git a/todo.md b/todo.md
index 64ef373..1854f4a 100644
--- a/todo.md
+++ b/todo.md
@@ -1,3 +1,7 @@
+# NOW
+- [ ] Check for functions in check.go
+
+# Sometime
 - [ ] Fix inconsensity in asm, change all structs to pointer
 - [ ] Fix inconsensity in Tests
 - [ ] Find a better way todo tests, like to generate a test case
diff --git a/typechecker/infer.go b/typechecker/infer.go
index 6f5883b..0f2825f 100644
--- a/typechecker/infer.go
+++ b/typechecker/infer.go
@@ -30,15 +30,16 @@ func (c *Checker) inferDeclaration(decl ast.Declaration) (tast.Declaration, erro
 	switch decl := decl.(type) {
 	case *ast.FunctionDeclaration:
 		vars := make(Variables)
-		arguments := []tast.Argument{}
+		parameters := []tast.Parameter{}
 		for _, param := range decl.Parameters {
 			t, ok := types.From(param.Type)
 			if !ok {
 				return nil, c.error(decl.Token, "could not find the type %q for argument %q", param.Type, param.Name)
 			}
 			vars[param.Name] = t
-			arguments = append(arguments, tast.Argument{Name: param.Name, Type: t})
+			parameters = append(parameters, tast.Parameter{Name: param.Name, Type: t})
 		}
+		// vars[decl.Name] = &types.FunctionType{ReturnType: }
 		body, err := c.inferExpression(vars, decl.Body)
 		c.functionVariables[decl.Name] = vars
 
@@ -46,7 +47,7 @@ func (c *Checker) inferDeclaration(decl ast.Declaration) (tast.Declaration, erro
 			return nil, err
 		}
 
-		return &tast.FunctionDeclaration{Token: decl.Token, Args: arguments, Body: body, ReturnType: body.Type(), Name: decl.Name}, nil
+		return &tast.FunctionDeclaration{Token: decl.Token, Args: parameters, Body: body, ReturnType: body.Type(), Name: decl.Name}, nil
 	}
 	return nil, errors.New("unhandled declaration in type inferer")
 }
@@ -173,6 +174,13 @@ func (c *Checker) inferExpression(vars Variables, expr ast.Expression) (tast.Exp
 		vr.VariableType = t
 
 		return vr, nil
+	case *ast.FunctionCall:
+		fc := &tast.FunctionCall{Identifier: expr.Identifier, Token: expr.Token}
+
+		t, ok := vars[expr.Identifier]
+		if !ok {
+			return fc, c.error(expr.Token, "could not get type for function %q", fc.Identifier)
+		}
 	default:
 		panic(fmt.Sprintf("unexpected ast.Expression: %#v", expr))
 	}
diff --git a/typechecker/variable_resolution.go b/typechecker/variable_resolution.go
index 15fa022..1730308 100644
--- a/typechecker/variable_resolution.go
+++ b/typechecker/variable_resolution.go
@@ -79,6 +79,7 @@ func VarResolve(p *ast.Program) (map[string]Scope, error) {
 			}
 
 			s := Scope{Variables: make(map[string]Var)}
+			s.Set(d.Name, d.Name)
 			for i, param := range d.Parameters {
 				uniq := s.SetUniq(param.Name)
 				d.Parameters[i].Name = uniq
@@ -163,6 +164,15 @@ func VarResolveExpr(s *Scope, e ast.Expression) error {
 		e.Identifier = v.Name
 	case *ast.BooleanExpression:
 	case *ast.IntegerExpression:
+	case *ast.FunctionCall:
+		newName, ok := s.Get(e.Identifier)
+		if !ok {
+			return errorf(e.Token, "function %q not found", e.Identifier)
+		}
+		for _, arg := range e.Arguments {
+			VarResolveExpr(s, arg)
+		}
+		e.Identifier = newName.Name
 	default:
 		panic(fmt.Sprintf("unexpected ast.Expression: %#v", e))
 	}
diff --git a/types/types.go b/types/types.go
index 6aff11e..96e9204 100644
--- a/types/types.go
+++ b/types/types.go
@@ -1,6 +1,10 @@
 package types
 
-import "robaertschi.xyz/robaertschi/tt/ast"
+import (
+	"strings"
+
+	"robaertschi.xyz/robaertschi/tt/ast"
+)
 
 type Type interface {
 	// Checks if the two types are the same
@@ -45,6 +49,51 @@ func (ti *TypeId) Name() string {
 	return ti.name
 }
 
+type FunctionType struct {
+	ReturnType Type
+	Parameters []Type
+}
+
+func (ft *FunctionType) SupportsBinaryOperator(op ast.BinaryOperator) bool {
+	return false
+}
+
+func (ft *FunctionType) IsSameType(t Type) bool {
+	if ft2, ok := t.(*FunctionType); ok {
+		if !ft.ReturnType.IsSameType(ft2.ReturnType) {
+			return false
+		}
+
+		if len(ft.Parameters) != len(ft2.Parameters) {
+			return false
+		}
+
+		for i, t := range ft.Parameters {
+			if !t.IsSameType(ft2.Parameters[i]) {
+				return false
+			}
+		}
+	}
+	return false
+}
+
+func (ft *FunctionType) Name() string {
+	b := strings.Builder{}
+
+	b.WriteString("fn(")
+
+	for i, param := range ft.Parameters {
+		b.WriteString(param.Name())
+		if i < (len(ft.Parameters) - 1) {
+			b.WriteRune(',')
+		}
+	}
+
+	b.WriteString("): " + ft.ReturnType.Name())
+
+	return b.String()
+}
+
 var types map[string]Type = make(map[string]Type)
 
 func New(id int64, name string) Type {