diff --git a/src/ast.rs b/src/ast.rs
index 30091ef..4dbdc26 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -2,6 +2,7 @@ mod basic;
 mod call;
 mod expr;
 mod field;
+mod func_def;
 mod lit;
 mod table_constr;
 mod table_destr;
@@ -13,6 +14,7 @@ pub use self::basic::*;
 pub use self::call::*;
 pub use self::expr::*;
 pub use self::field::*;
+pub use self::func_def::*;
 pub use self::lit::*;
 pub use self::table_constr::*;
 pub use self::table_destr::*;
diff --git a/src/ast/expr.rs b/src/ast/expr.rs
index 8a0cf04..d156271 100644
--- a/src/ast/expr.rs
+++ b/src/ast/expr.rs
@@ -3,6 +3,7 @@ use crate::span::{HasSpan, Span};
 use super::basic::Space;
 use super::call::Call;
 use super::field::Field;
+use super::func_def::FuncDef;
 use super::lit::Lit;
 use super::table_constr::TableConstr;
 use super::table_destr::TableDestr;
@@ -38,6 +39,7 @@ pub enum Expr {
     Var(Var),
     TableConstr(TableConstr),
     TableDestr(TableDestr),
+    FuncDef(FuncDef),
 
     /// `(a)`
     ///
@@ -93,6 +95,7 @@ impl HasSpan for Expr {
             Expr::Var(var) => var.span(),
             Expr::TableConstr(constr) => constr.span(),
             Expr::TableDestr(destr) => destr.span(),
+            Expr::FuncDef(def) => def.span(),
             Expr::Paren { span, .. } => *span,
             Expr::Neg { span, .. } => *span,
             Expr::Not { span, .. } => *span,
diff --git a/src/ast/func_def.rs b/src/ast/func_def.rs
new file mode 100644
index 0000000..b7eaded
--- /dev/null
+++ b/src/ast/func_def.rs
@@ -0,0 +1,95 @@
+use crate::span::{HasSpan, Span};
+
+use super::{Expr, Ident, Space, TablePattern};
+
+#[derive(Debug, Clone)]
+pub enum FuncDef {
+    /// `function() a
+    ///
+    /// Structure: `function s0 ( s1 ) s2 body`
+    AnonNoArg {
+        s0: Space,
+        s1: Space,
+        s2: Space,
+        body: Box<Expr>,
+        span: Span,
+    },
+
+    /// `function(foo) a`
+    ///
+    /// Structure: `function s0 ( s1 arg s2 ) s3 body`
+    AnonArg {
+        s0: Space,
+        s1: Space,
+        arg: Ident,
+        s2: Space,
+        s3: Space,
+        body: Box<Expr>,
+        span: Span,
+    },
+
+    /// `function{..} a`
+    ///
+    /// Structure: `function s0 pattern s1 body`
+    AnonDestr {
+        s0: Space,
+        pattern: TablePattern,
+        s1: Space,
+        body: Box<Expr>,
+        span: Span,
+    },
+
+    /// `function foo() a`
+    ///
+    /// Structure: `function s0 name s1 ( s2 ) s3 body`
+    NamedNoArg {
+        s0: Space,
+        name: Ident,
+        s1: Space,
+        s2: Space,
+        s3: Space,
+        body: Box<Expr>,
+        span: Span,
+    },
+
+    /// `function foo(bar) a`
+    ///
+    /// Structure: `function s0 name s1 ( s2 arg s3 ) s4 body`
+    NamedArg {
+        s0: Space,
+        name: Ident,
+        s1: Space,
+        s2: Space,
+        arg: Ident,
+        s3: Space,
+        s4: Space,
+        body: Box<Expr>,
+        span: Span,
+    },
+
+    /// `function foo{..} a`
+    ///
+    /// Structure: `function s0 name s1 pattern s2 body`
+    NamedDestr {
+        s0: Space,
+        name: Ident,
+        s1: Space,
+        pattern: TablePattern,
+        s2: Space,
+        body: Box<Expr>,
+        span: Span,
+    },
+}
+
+impl HasSpan for FuncDef {
+    fn span(&self) -> Span {
+        match self {
+            FuncDef::AnonNoArg { span, .. } => *span,
+            FuncDef::AnonArg { span, .. } => *span,
+            FuncDef::AnonDestr { span, .. } => *span,
+            FuncDef::NamedNoArg { span, .. } => *span,
+            FuncDef::NamedArg { span, .. } => *span,
+            FuncDef::NamedDestr { span, .. } => *span,
+        }
+    }
+}