diff --git a/opensmtpd-derive/src/attributes.rs b/opensmtpd-derive/src/attributes.rs
new file mode 100644
index 0000000..844f38e
--- /dev/null
+++ b/opensmtpd-derive/src/attributes.rs
@@ -0,0 +1,113 @@
+// Copyright (c) 2019 Rodolphe Bréard
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use syn::parse::{Parse, ParseStream};
+use syn::punctuated::Punctuated;
+use syn::{parenthesized, Ident, Result, Token};
+
+#[derive(Debug)]
+pub(crate) struct OpenSmtpdAttributes {
+    version: Ident,
+    subsystem: Ident,
+    events: Punctuated<Ident, Token![,]>,
+}
+
+impl Parse for OpenSmtpdAttributes {
+    fn parse(input: ParseStream) -> Result<Self> {
+        let version = input.parse()?;
+        let _: Token![,] = input.parse()?;
+        let subsystem = input.parse()?;
+        let _: Token![,] = input.parse()?;
+        let _match: Token![match] = input.parse()?;
+        let content;
+        let _ = parenthesized!(content in input);
+        let events = content.parse_terminated(Ident::parse)?;
+        Ok(OpenSmtpdAttributes {
+            version,
+            subsystem,
+            events,
+        })
+    }
+}
+
+impl OpenSmtpdAttributes {
+    pub(crate) fn get_version(&self) -> String {
+        format!(
+            "opensmtpd::entry::Version::{}",
+            self.version.to_string().to_uppercase()
+        )
+    }
+
+    pub(crate) fn get_subsystem(&self) -> String {
+        let subsystem = match self.subsystem.to_string().as_str() {
+            "smtp_in" => "SmtpIn",
+            "smtp_out" => "SmtpOut",
+            _ => "",
+        };
+        format!("opensmtpd::entry::Subsystem::{}", subsystem)
+    }
+
+    pub(crate) fn get_events(&self) -> String {
+        let events = if self
+            .events
+            .iter()
+            .any(|e| e.to_string().to_lowercase().as_str() == "all")
+        {
+            let lst = [
+                "LinkAuth",
+                "LinkConnect",
+                "LinkDisconnect",
+                "LinkIdentify",
+                "LinkReset",
+                "LinkTls",
+                "TxBegin",
+                "TxMail",
+                "TxRcpt",
+                "TxEnvelope",
+                "TxData",
+                "TxCommit",
+                "TxRollback",
+                "ProtocolClient",
+                "ProtocolServer",
+                "FilterResponse",
+                "Timeout",
+            ];
+            lst.iter()
+                .map(|e| format!("opensmtpd::entry::Event::{}", e))
+                .collect::<Vec<String>>()
+        } else {
+            self.events
+                .iter()
+                .map(|e| {
+                    let name = match e.to_string().as_str() {
+                        "link_auth" => "LinkAuth",
+                        "link_connect" => "LinkConnect",
+                        "link_disconnect" => "LinkDisconnect",
+                        "link_identify" => "LinkIdentify",
+                        "link_reset" => "LinkReset",
+                        "link_tls" => "LinkTls",
+                        "tx_begin" => "TxBegin",
+                        "tx_mail" => "TxMail",
+                        "tx_rcpt" => "TxRcpt",
+                        "tx_envelope" => "TxEnvelope",
+                        "tx_data" => "TxData",
+                        "tx_commit" => "TxCommit",
+                        "tx_rollback" => "TxRollback",
+                        "protocol_client" => "ProtocolClient",
+                        "protocol_server" => "ProtocolServer",
+                        "filter_response" => "FilterResponse",
+                        "timeout" => "Timeout",
+                        _ => "",
+                    };
+                    format!("opensmtpd::entry::Event::{}", name)
+                })
+                .collect::<Vec<String>>()
+        };
+        format!("[{}]", events.join(", "))
+    }
+}
diff --git a/opensmtpd-derive/src/lib.rs b/opensmtpd-derive/src/lib.rs
index a9ea598..e3863d7 100644
--- a/opensmtpd-derive/src/lib.rs
+++ b/opensmtpd-derive/src/lib.rs
@@ -8,113 +8,12 @@
 
 extern crate proc_macro;
 
+mod attributes;
+
+use attributes::OpenSmtpdAttributes;
 use proc_macro::TokenStream;
 use quote::quote;
-use syn::parse::{Parse, ParseStream};
-use syn::punctuated::Punctuated;
-use syn::{parenthesized, parse_macro_input, ExprArray, Ident, ItemFn, Result, Token, TypePath};
-
-#[derive(Debug)]
-struct OpenSmtpdAttributes {
-    version: Ident,
-    subsystem: Ident,
-    events: Punctuated<Ident, Token![,]>,
-}
-
-impl Parse for OpenSmtpdAttributes {
-    fn parse(input: ParseStream) -> Result<Self> {
-        let version = input.parse()?;
-        let _: Token![,] = input.parse()?;
-        let subsystem = input.parse()?;
-        let _: Token![,] = input.parse()?;
-        let _match: Token![match] = input.parse()?;
-        let content;
-        let _ = parenthesized!(content in input);
-        let events = content.parse_terminated(Ident::parse)?;
-        Ok(OpenSmtpdAttributes {
-            version,
-            subsystem,
-            events,
-        })
-    }
-}
-
-impl OpenSmtpdAttributes {
-    fn get_version(&self) -> String {
-        format!(
-            "opensmtpd::entry::Version::{}",
-            self.version.to_string().to_uppercase()
-        )
-    }
-
-    fn get_subsystem(&self) -> String {
-        let subsystem = match self.subsystem.to_string().as_str() {
-            "smtp_in" => "SmtpIn",
-            "smtp_out" => "SmtpOut",
-            _ => "",
-        };
-        format!("opensmtpd::entry::Subsystem::{}", subsystem)
-    }
-
-    fn get_events(&self) -> String {
-        let events = if self
-            .events
-            .iter()
-            .any(|e| e.to_string().to_lowercase().as_str() == "all")
-        {
-            let lst = [
-                "LinkAuth",
-                "LinkConnect",
-                "LinkDisconnect",
-                "LinkIdentify",
-                "LinkReset",
-                "LinkTls",
-                "TxBegin",
-                "TxMail",
-                "TxRcpt",
-                "TxEnvelope",
-                "TxData",
-                "TxCommit",
-                "TxRollback",
-                "ProtocolClient",
-                "ProtocolServer",
-                "FilterResponse",
-                "Timeout",
-            ];
-            lst.iter()
-                .map(|e| format!("opensmtpd::entry::Event::{}", e))
-                .collect::<Vec<String>>()
-        } else {
-            self.events
-                .iter()
-                .map(|e| {
-                    let name = match e.to_string().as_str() {
-                        "link_auth" => "LinkAuth",
-                        "link_connect" => "LinkConnect",
-                        "link_disconnect" => "LinkDisconnect",
-                        "link_identify" => "LinkIdentify",
-                        "link_reset" => "LinkReset",
-                        "link_tls" => "LinkTls",
-                        "tx_begin" => "TxBegin",
-                        "tx_mail" => "TxMail",
-                        "tx_rcpt" => "TxRcpt",
-                        "tx_envelope" => "TxEnvelope",
-                        "tx_data" => "TxData",
-                        "tx_commit" => "TxCommit",
-                        "tx_rollback" => "TxRollback",
-                        "protocol_client" => "ProtocolClient",
-                        "protocol_server" => "ProtocolServer",
-                        "filter_response" => "FilterResponse",
-                        "timeout" => "Timeout",
-                        _ => "",
-                    };
-                    format!("opensmtpd::entry::Event::{}", name)
-                })
-                .collect::<Vec<String>>()
-        };
-        format!("[{}]", events.join(", "))
-    }
-}
+use syn::{parse_macro_input, ExprArray, ItemFn, TypePath};
 
 macro_rules! parse_item {
     ($item: expr, $type: ty) => {