refactor: reorganize and improve macros

4 files changed, 430 insertions, 299 deletions

diff --git a/syrette_macros/src/factory_type_alias.rs b/syrette_macros/src/factory_type_alias.rs
new file mode 100644
index 0000000..82e2315
--- /dev/null
+++ b/syrette_macros/src/factory_type_alias.rs
@@ -0,0 +1,83 @@
+use syn::parse::{Parse, ParseStream};
+use syn::{GenericArgument, ItemType, Path, Type, TypeParamBound, TypeTuple};
+
+pub struct FactoryTypeAlias
+{
+    pub type_alias: ItemType,
+    pub factory_interface: Path,
+    pub arg_types: TypeTuple,
+    pub return_type: Type,
+}
+
+impl Parse for FactoryTypeAlias
+{
+    fn parse(input: ParseStream) -> syn::Result<Self>
+    {
+        let type_alias = match input.parse::<ItemType>() {
+            Ok(type_alias) => Ok(type_alias),
+            Err(_) => Err(input.error("Expected a type alias")),
+        }?;
+
+        let aliased_trait = match &type_alias.ty.as_ref() {
+            Type::TraitObject(alias_type) => Ok(alias_type),
+            &_ => Err(input.error("Expected the aliased type to be a trait")),
+        }?;
+
+        if aliased_trait.bounds.len() != 1 {
+            return Err(input.error("Expected the aliased trait to have a single bound."));
+        }
+
+        let bound_path = &match aliased_trait.bounds.first().unwrap() {
+            TypeParamBound::Trait(trait_bound) => Ok(trait_bound),
+            &_ => {
+                Err(input.error("Expected the bound of the aliased trait to be a trait"))
+            }
+        }?
+        .path;
+
+        if bound_path.segments.is_empty()
+            || bound_path.segments.last().unwrap().ident != "IFactory"
+        {
+            return Err(input
+                .error("Expected the bound of the aliased trait to be 'dyn IFactory'"));
+        }
+
+        let angle_bracketed_args = match &bound_path.segments.last().unwrap().arguments {
+            syn::PathArguments::AngleBracketed(angle_bracketed_args) => {
+                Ok(angle_bracketed_args)
+            }
+            &_ => {
+                Err(input.error("Expected angle bracketed arguments for 'dyn IFactory'"))
+            }
+        }?;
+
+        let arg_types = match &angle_bracketed_args.args[0] {
+            GenericArgument::Type(arg_types_type) => match arg_types_type {
+                Type::Tuple(arg_types) => Ok(arg_types),
+                &_ => Err(input.error(concat!(
+                    "Expected the first angle bracketed argument ",
+                    "of 'dyn IFactory' to be a type tuple"
+                ))),
+            },
+            &_ => Err(input.error(concat!(
+                "Expected the first angle bracketed argument ",
+                "of 'dyn IFactory' to be a type"
+            ))),
+        }?;
+
+        let return_type = match &angle_bracketed_args.args[1] {
+            GenericArgument::Type(arg_type) => Ok(arg_type),
+            &_ => Err(input.error(concat!(
+                "Expected the second angle bracketed argument ",
+                "of 'dyn IFactory' to be a type"
+            ))),
+        }?;
+
+        Ok(Self {
+            type_alias: type_alias.clone(),
+            factory_interface: bound_path.clone(),
+            arg_types: arg_types.clone(),
+            return_type: return_type.clone(),
+        })
+    }
+}
diff --git a/syrette_macros/src/injectable_impl.rs b/syrette_macros/src/injectable_impl.rs
new file mode 100644
index 0000000..e7d1b54
--- /dev/null
+++ b/syrette_macros/src/injectable_impl.rs
@@ -0,0 +1,244 @@
+use quote::{quote, ToTokens};
+use syn::parse::{Parse, ParseStream};
+use syn::{
+    parse_str, punctuated::Punctuated, token::Comma, ExprMethodCall, FnArg,
+    GenericArgument, Ident, ImplItem, ImplItemMethod, ItemImpl, Path, PathArguments,
+    Type, TypePath,
+};
+
+const DI_CONTAINER_VAR_NAME: &str = "di_container";
+
+pub struct InjectableImpl
+{
+    pub dependency_types: Vec<Type>,
+    pub self_type: Type,
+    pub original_impl: ItemImpl,
+}
+
+impl Parse for InjectableImpl
+{
+    fn parse(input: ParseStream) -> syn::Result<Self>
+    {
+        match input.parse::<ItemImpl>() {
+            Ok(impl_parsed_input) => {
+                match Self::_get_dependency_types(&impl_parsed_input) {
+                    Ok(dependency_types) => Ok(Self {
+                        dependency_types,
+                        self_type: impl_parsed_input.self_ty.as_ref().clone(),
+                        original_impl: impl_parsed_input,
+                    }),
+                    Err(error_msg) => Err(input.error(error_msg)),
+                }
+            }
+            Err(_) => Err(input.error("Expected an impl")),
+        }
+    }
+}
+
+impl InjectableImpl
+{
+    pub fn expand(&self) -> proc_macro2::TokenStream
+    {
+        let original_impl = &self.original_impl;
+        let self_type = &self.self_type;
+
+        let di_container_var: Ident = parse_str(DI_CONTAINER_VAR_NAME).unwrap();
+
+        let get_dependencies = Self::_create_get_dependencies(&self.dependency_types);
+
+        quote! {
+            #original_impl
+
+            impl syrette::interfaces::injectable::Injectable for #self_type {
+                fn resolve(
+                    #di_container_var: &syrette::DIContainer
+                ) -> error_stack::Result<
+                    syrette::ptr::InterfacePtr<Self>,
+                    syrette::errors::injectable::ResolveError>
+                {
+                    use error_stack::ResultExt;
+
+                    return Ok(syrette::ptr::InterfacePtr::new(Self::new(
+                        #(#get_dependencies
+                            .change_context(syrette::errors::injectable::ResolveError)
+                            .attach_printable(
+                                format!(
+                                    "Unable to resolve a dependency of {}",
+                                    std::any::type_name::<#self_type>()
+                                )
+                            )?
+                        ),*
+                    )));
+                }
+            }
+        }
+    }
+
+    fn _create_get_dependencies(dependency_types: &[Type]) -> Vec<ExprMethodCall>
+    {
+        dependency_types
+            .iter()
+            .filter_map(|dep_type| match dep_type {
+                Type::TraitObject(dep_type_trait) => Some(
+                    parse_str(
+                        format!(
+                            "{}.get::<{}>()",
+                            DI_CONTAINER_VAR_NAME,
+                            dep_type_trait.to_token_stream()
+                        )
+                        .as_str(),
+                    )
+                    .unwrap(),
+                ),
+                Type::Path(dep_type_path) => {
+                    let dep_type_path_str = Self::_path_to_string(&dep_type_path.path);
+
+                    let get_method_name = if dep_type_path_str.ends_with("Factory") {
+                        "get_factory"
+                    } else {
+                        "get"
+                    };
+
+                    Some(
+                        parse_str(
+                            format!(
+                                "{}.{}::<{}>()",
+                                DI_CONTAINER_VAR_NAME, get_method_name, dep_type_path_str
+                            )
+                            .as_str(),
+                        )
+                        .unwrap(),
+                    )
+                }
+                &_ => None,
+            })
+            .collect()
+    }
+
+    fn _find_method_by_name<'impl_lt>(
+        item_impl: &'impl_lt ItemImpl,
+        method_name: &'static str,
+    ) -> Option<&'impl_lt ImplItemMethod>
+    {
+        let impl_items = &item_impl.items;
+
+        impl_items
+            .iter()
+            .filter_map(|impl_item| match impl_item {
+                ImplItem::Method(method_item) => Some(method_item),
+                &_ => None,
+            })
+            .find(|method_item| method_item.sig.ident == method_name)
+    }
+
+    fn get_has_fn_args_self(fn_args: &Punctuated<FnArg, Comma>) -> bool
+    {
+        fn_args.iter().any(|arg| match arg {
+            FnArg::Receiver(_) => true,
+            &_ => false,
+        })
+    }
+
+    fn _get_fn_arg_type_paths(fn_args: &Punctuated<FnArg, Comma>) -> Vec<&TypePath>
+    {
+        fn_args
+            .iter()
+            .filter_map(|arg| match arg {
+                FnArg::Typed(typed_fn_arg) => match typed_fn_arg.ty.as_ref() {
+                    Type::Path(arg_type_path) => Some(arg_type_path),
+                    Type::Reference(ref_type_path) => match ref_type_path.elem.as_ref() {
+                        Type::Path(arg_type_path) => Some(arg_type_path),
+                        &_ => None,
+                    },
+                    &_ => None,
+                },
+                FnArg::Receiver(_receiver_fn_arg) => None,
+            })
+            .collect()
+    }
+
+    fn _path_to_string(path: &Path) -> String
+    {
+        path.segments
+            .pairs()
+            .fold(String::new(), |mut acc, segment_pair| {
+                let segment_ident = &segment_pair.value().ident;
+
+                acc.push_str(segment_ident.to_string().as_str());
+
+                let opt_colon_two = segment_pair.punct();
+
+                match opt_colon_two {
+                    Some(colon_two) => {
+                        acc.push_str(colon_two.to_token_stream().to_string().as_str())
+                    }
+                    None => {}
+                }
+
+                acc
+            })
+    }
+
+    fn _is_type_path_ptr(type_path: &TypePath) -> bool
+    {
+        let arg_type_path_string = Self::_path_to_string(&type_path.path);
+
+        arg_type_path_string == "InterfacePtr"
+            || arg_type_path_string == "ptr::InterfacePtr"
+            || arg_type_path_string == "syrrete::ptr::InterfacePtr"
+            || arg_type_path_string == "FactoryPtr"
+            || arg_type_path_string == "ptr::FactoryPtr"
+            || arg_type_path_string == "syrrete::ptr::FactoryPtr"
+    }
+
+    fn _get_dependency_types(item_impl: &ItemImpl) -> Result<Vec<Type>, &'static str>
+    {
+        let new_method_impl_item = match Self::_find_method_by_name(item_impl, "new") {
+            Some(method_item) => Ok(method_item),
+            None => Err("Missing a 'new' method"),
+        }?;
+
+        let new_method_args = &new_method_impl_item.sig.inputs;
+
+        if Self::get_has_fn_args_self(new_method_args) {
+            return Err("Unexpected self argument in 'new' method");
+        }
+
+        let new_method_arg_type_paths = Self::_get_fn_arg_type_paths(new_method_args);
+
+        if new_method_arg_type_paths
+            .iter()
+            .any(|arg_type_path| !Self::_is_type_path_ptr(arg_type_path))
+        {
+            return Err("All argument types in 'new' method must ptr types");
+        }
+
+        Ok(new_method_arg_type_paths
+            .iter()
+            .filter_map(|arg_type_path| {
+                // Assume the type path has a last segment.
+                let last_path_segment = arg_type_path.path.segments.last().unwrap();
+
+                match &last_path_segment.arguments {
+                    PathArguments::AngleBracketed(angle_bracketed_generic_args) => {
+                        let generic_args = &angle_bracketed_generic_args.args;
+
+                        let opt_first_generic_arg = generic_args.first();
+
+                        // Assume a first generic argument exists because InterfacePtr and
+                        // FactoryPtr requires one
+                        let first_generic_arg = opt_first_generic_arg.as_ref().unwrap();
+
+                        match first_generic_arg {
+                            GenericArgument::Type(first_generic_arg_type) => {
+                                Some(first_generic_arg_type.clone())
+                            }
+                            &_ => None,
+                        }
+                    }
+                    &_ => None,
+                }
+            })
+            .collect())
+    }
+}
diff --git a/syrette_macros/src/injectable_macro_args.rs b/syrette_macros/src/injectable_macro_args.rs
new file mode 100644
index 0000000..4ef4389
--- /dev/null
+++ b/syrette_macros/src/injectable_macro_args.rs
@@ -0,0 +1,17 @@
+use syn::parse::{Parse, ParseStream};
+use syn::TypePath;
+
+pub struct InjectableMacroArgs
+{
+    pub interface: TypePath,
+}
+
+impl Parse for InjectableMacroArgs
+{
+    fn parse(input: ParseStream) -> syn::Result<Self>
+    {
+        Ok(Self {
+            interface: input.parse()?,
+        })
+    }
+}
diff --git a/syrette_macros/src/lib.rs b/syrette_macros/src/lib.rs
index 91a0562..3145b5f 100644
--- a/syrette_macros/src/lib.rs
+++ b/syrette_macros/src/lib.rs
@@ -1,162 +1,21 @@
 use proc_macro::TokenStream;
-use quote::{quote, ToTokens};
-use syn::{
-    parse, parse_macro_input, parse_str, punctuated::Punctuated, token::Comma,
-    AttributeArgs, ExprMethodCall, FnArg, GenericArgument, ImplItem, ItemImpl, ItemType,
-    Meta, NestedMeta, Path, PathArguments, Type, TypeParamBound, TypePath,
-};
+use quote::quote;
+use syn::{parse, parse_macro_input};
 
+mod factory_type_alias;
+mod injectable_impl;
+mod injectable_macro_args;
 mod libs;
 
+use factory_type_alias::FactoryTypeAlias;
+use injectable_impl::InjectableImpl;
+use injectable_macro_args::InjectableMacroArgs;
 use libs::intertrait_macros::{
     args::{Casts, Flag, Targets},
     gen_caster::generate_caster,
 };
 
-const NO_INTERFACE_ARG_ERR_MESSAGE: &str =
-    "Expected a argument specifying a interface trait";
-
-const INVALID_ARG_ERR_MESSAGE: &str = "Invalid argument passed";
-
-const INVALID_ITEM_TYPE_ERR_MESSAGE: &str =
-    "The attached to item is not a trait implementation";
-
-const IMPL_NO_NEW_METHOD_ERR_MESSAGE: &str =
-    "The attached to trait implementation is missing a new method";
-
-const IMPL_NEW_METHOD_SELF_PARAM_ERR_MESSAGE: &str =
-    "The new method of the attached to trait implementation cannot have a self parameter";
-
-const IMPL_NEW_METHOD_PARAM_TYPES_ERR_MESSAGE: &str = concat!(
-    "All parameters of the new method of the attached to trait implementation ",
-    "must be either syrette::ptr::InterfacePtr or syrrete::ptr::FactoryPtr (for factories)"
-);
-
-const INVALID_ALIASED_FACTORY_TRAIT_ERR_MESSAGE: &str =
-    "Invalid aliased trait. Must be 'dyn IFactory'";
-
-const INVALID_ALIASED_FACTORY_ARGS_ERR_MESSAGE: &str =
-    "Invalid arguments for 'dyn IFactory'";
-
-fn path_to_string(path: &Path) -> String
-{
-    return path
-        .segments
-        .pairs()
-        .fold(String::new(), |mut acc, segment_pair| {
-            let segment_ident = &segment_pair.value().ident;
-
-            acc.push_str(segment_ident.to_string().as_str());
-
-            let opt_colon_two = segment_pair.punct();
-
-            match opt_colon_two {
-                Some(colon_two) => {
-                    acc.push_str(colon_two.to_token_stream().to_string().as_str())
-                }
-                None => {}
-            }
-
-            acc
-        });
-}
-
-fn get_fn_args_has_self(fn_args: &Punctuated<FnArg, Comma>) -> bool
-{
-    return fn_args.iter().any(|arg| match arg {
-        FnArg::Receiver(_) => true,
-        &_ => false,
-    });
-}
-
-fn get_fn_arg_type_paths(fn_args: &Punctuated<FnArg, Comma>) -> Vec<TypePath>
-{
-    return fn_args.iter().fold(Vec::<TypePath>::new(), |mut acc, arg| {
-        match arg {
-            FnArg::Typed(typed_fn_arg) => match typed_fn_arg.ty.as_ref() {
-                Type::Path(arg_type_path) => acc.push(arg_type_path.clone()),
-                Type::Reference(ref_type_path) => match ref_type_path.elem.as_ref() {
-                    Type::Path(arg_type_path) => acc.push(arg_type_path.clone()),
-                    &_ => {}
-                },
-                &_ => {}
-            },
-            FnArg::Receiver(_receiver_fn_arg) => {}
-        }
-
-        acc
-    });
-}
-
-fn get_dependency_types(item_impl: &ItemImpl) -> Vec<Type>
-{
-    let impl_items = &item_impl.items;
-
-    let opt_new_method_impl_item = impl_items.iter().find(|item| match item {
-        ImplItem::Method(method_item) => method_item.sig.ident == "new",
-        &_ => false,
-    });
-
-    let new_method_impl_item = match opt_new_method_impl_item {
-        Some(item) => match item {
-            ImplItem::Method(method_item) => method_item,
-            &_ => panic!("{}", IMPL_NO_NEW_METHOD_ERR_MESSAGE),
-        },
-        None => panic!("{}", IMPL_NO_NEW_METHOD_ERR_MESSAGE),
-    };
-
-    let new_method_inputs = &new_method_impl_item.sig.inputs;
-
-    if get_fn_args_has_self(new_method_inputs) {
-        panic!("{}", IMPL_NEW_METHOD_SELF_PARAM_ERR_MESSAGE)
-    }
-
-    let new_method_arg_type_paths = get_fn_arg_type_paths(new_method_inputs);
-
-    return new_method_arg_type_paths.iter().fold(
-        Vec::<Type>::new(),
-        |mut acc, arg_type_path| {
-            let arg_type_path_string = path_to_string(&arg_type_path.path);
-
-            if arg_type_path_string != "InterfacePtr"
-                && arg_type_path_string != "ptr::InterfacePtr"
-                && arg_type_path_string != "syrrete::ptr::InterfacePtr"
-                && arg_type_path_string != "FactoryPtr"
-                && arg_type_path_string != "ptr::FactoryPtr"
-                && arg_type_path_string != "syrrete::ptr::FactoryPtr"
-            {
-                panic!("{}", IMPL_NEW_METHOD_PARAM_TYPES_ERR_MESSAGE);
-            }
-
-            // Assume the type path has a last segment.
-            let last_path_segment = arg_type_path.path.segments.last().unwrap();
-
-            match &last_path_segment.arguments {
-                PathArguments::AngleBracketed(angle_bracketed_generic_args) => {
-                    let generic_args = &angle_bracketed_generic_args.args;
-
-                    let opt_first_generic_arg = generic_args.first();
-
-                    // Assume a first generic argument exists because InterfacePtr and
-                    // FactoryPtr requires one
-                    let first_generic_arg = opt_first_generic_arg.as_ref().unwrap();
-
-                    match first_generic_arg {
-                        GenericArgument::Type(first_generic_arg_type) => {
-                            acc.push(first_generic_arg_type.clone());
-                        }
-                        &_ => {}
-                    }
-                }
-                &_ => {}
-            }
-
-            acc
-        },
-    );
-}
-
-/// Makes a struct injectable. Therefore usable with `DIContainer`.
+/// Makes a struct injectable. Thereby usable with `DIContainer`.
 ///
 /// # Arguments
 ///
@@ -166,15 +25,28 @@ fn get_dependency_types(item_impl: &ItemImpl) -> Vec<Type>
 /// ```
 /// trait IConfigReader
 /// {
-///     fn read_config() -> Config;
+///     fn read_config(&self) -> Config;
+/// }
+///
+/// struct ConfigReader
+/// {
+///     _file_reader: InterfacePtr<IFileReader>,
 /// }
 ///
-/// struct ConfigReader {}
+/// impl ConfigReader
+/// {
+///     fn new(file_reader: InterfacePtr<IFileReader>) -> Self
+///     {
+///         Self {
+///             _file_reader: file_reader
+///         }
+///     }
+/// }
 ///
 /// #[injectable(IConfigReader)]
 /// impl IConfigReader for ConfigReader
 /// {
-///     fn read_config() -> Config
+///     fn read_config(&self) -> Config
 ///     {
 ///         // Stuff here
 ///     }
@@ -183,175 +55,90 @@ fn get_dependency_types(item_impl: &ItemImpl) -> Vec<Type>
 #[proc_macro_attribute]
 pub fn injectable(args_stream: TokenStream, impl_stream: TokenStream) -> TokenStream
 {
-    let args = parse_macro_input!(args_stream as AttributeArgs);
+    let InjectableMacroArgs {
+        interface: interface_type_path,
+    } = parse_macro_input!(args_stream);
 
-    if args.is_empty() {
-        panic!("{}", NO_INTERFACE_ARG_ERR_MESSAGE);
-    }
+    let injectable_impl: InjectableImpl = parse(impl_stream).unwrap();
 
-    if args.len() > 1 {
-        panic!("Only a single argument is expected");
-    }
-
-    let interface_path = match &args[0] {
-        NestedMeta::Meta(arg_meta) => match arg_meta {
-            Meta::Path(path_arg) => path_arg,
-            &_ => panic!("{}", INVALID_ARG_ERR_MESSAGE),
-        },
-        &_ => panic!("{}", INVALID_ARG_ERR_MESSAGE),
-    };
-
-    let item_impl: ItemImpl = match parse(impl_stream) {
-        Ok(impl_parsed) => impl_parsed,
-        Err(_) => {
-            panic!("{}", INVALID_ITEM_TYPE_ERR_MESSAGE)
-        }
-    };
-
-    let self_type = item_impl.self_ty.as_ref();
-
-    let self_type_path = match self_type {
-        Type::Path(path_self_type) => path_self_type.path.clone(),
-        &_ => parse_str("invalid_type").unwrap(),
-    };
-
-    let dependency_types = get_dependency_types(&item_impl);
+    let expanded_injectable_impl = injectable_impl.expand();
 
-    let get_dependencies = dependency_types.iter().fold(
-        Vec::<ExprMethodCall>::new(),
-        |mut acc, dep_type| {
-            match dep_type {
-                Type::TraitObject(dep_type_trait) => {
-                    acc.push(
-                        parse_str(
-                            format!(
-                                "di_container.get::<{}>()",
-                                dep_type_trait.to_token_stream()
-                            )
-                            .as_str(),
-                        )
-                        .unwrap(),
-                    );
-                }
-                Type::Path(dep_type_path) => {
-                    let dep_type_path_str = path_to_string(&dep_type_path.path);
-
-                    let get_method_name = if dep_type_path_str.ends_with("Factory") {
-                        "get_factory"
-                    } else {
-                        "get"
-                    };
-
-                    acc.push(
-                        parse_str(
-                            format!(
-                                "di_container.{}::<{}>()",
-                                get_method_name, dep_type_path_str
-                            )
-                            .as_str(),
-                        )
-                        .unwrap(),
-                    );
-                }
-                &_ => {}
-            }
-
-            acc
-        },
-    );
+    let self_type = &injectable_impl.self_type;
 
     quote! {
-        #item_impl
+        #expanded_injectable_impl
 
-        impl syrette::interfaces::injectable::Injectable for #self_type_path {
-            fn resolve(
-                di_container: &syrette::DIContainer
-            ) -> error_stack::Result<
-                syrette::ptr::InterfacePtr<Self>,
-                syrette::errors::injectable::ResolveError>
-            {
-                use error_stack::ResultExt;
-
-                return Ok(syrette::ptr::InterfacePtr::new(Self::new(
-                    #(#get_dependencies
-                        .change_context(syrette::errors::injectable::ResolveError)
-                        .attach_printable(
-                            format!(
-                                "Unable to resolve a dependency of {}",
-                                std::any::type_name::<#self_type_path>()
-                            )
-                        )?
-                    ),*
-                )));
-            }
-        }
-
-        syrette::castable_to!(#self_type_path => #interface_path);
+        syrette::castable_to!(#self_type => #interface_type_path);
     }
     .into()
 }
 
+/// Makes a type alias usable as a factory interface.
+///
+/// # Examples
+/// ```
+/// trait IUser
+/// {
+///     fn name(&self) -> String;
+///     fn age(&self) -> i32;
+/// }
+///
+/// struct User
+/// {
+///     _name: String,
+///     _age: i32,
+/// }
+///
+/// impl User
+/// {
+///     fn new(name: String, age: i32) -> Self
+///     {
+///         Self {
+///             _name: name,
+///             _age: age,
+///         }
+///     }
+/// }
+///
+/// impl IUser for User
+/// {
+///     fn name(&self) -> String
+///     {
+///         self._name
+///     }
+///
+///     fn age(&self) -> i32
+///     {
+///         self._age
+///     }
+/// }
+///
+/// type UserFactory = dyn IFactory<(String, i32), dyn IUser>;
+/// ```
 #[proc_macro_attribute]
 pub fn factory(_: TokenStream, type_alias_stream: TokenStream) -> TokenStream
 {
-    let type_alias: ItemType = parse(type_alias_stream).unwrap();
-
-    let aliased_trait = match &type_alias.ty.as_ref() {
-        Type::TraitObject(alias_type) => alias_type,
-        &_ => panic!("{}", INVALID_ALIASED_FACTORY_TRAIT_ERR_MESSAGE),
-    };
-
-    if aliased_trait.bounds.len() != 1 {
-        panic!("{}", INVALID_ALIASED_FACTORY_TRAIT_ERR_MESSAGE);
-    }
-
-    let type_bound = aliased_trait.bounds.first().unwrap();
-
-    let trait_bound = match type_bound {
-        TypeParamBound::Trait(trait_bound) => trait_bound,
-        &_ => panic!("{}", INVALID_ALIASED_FACTORY_TRAIT_ERR_MESSAGE),
-    };
-
-    let trait_bound_path = &trait_bound.path;
-
-    if trait_bound_path.segments.is_empty()
-        || trait_bound_path.segments.last().unwrap().ident != "IFactory"
-    {
-        panic!("{}", INVALID_ALIASED_FACTORY_TRAIT_ERR_MESSAGE);
-    }
-
-    let factory_path_segment = trait_bound_path.segments.last().unwrap();
-
-    let factory_path_segment_args = &match &factory_path_segment.arguments {
-        syn::PathArguments::AngleBracketed(args) => args,
-        &_ => panic!("{}", INVALID_ALIASED_FACTORY_ARGS_ERR_MESSAGE),
-    }
-    .args;
-
-    let factory_arg_types_type = match &factory_path_segment_args[0] {
-        GenericArgument::Type(arg_type) => arg_type,
-        &_ => panic!("{}", INVALID_ALIASED_FACTORY_ARGS_ERR_MESSAGE),
-    };
-
-    let factory_return_type = match &factory_path_segment_args[1] {
-        GenericArgument::Type(arg_type) => arg_type,
-        &_ => panic!("{}", INVALID_ALIASED_FACTORY_ARGS_ERR_MESSAGE),
-    };
+    let FactoryTypeAlias {
+        type_alias,
+        factory_interface,
+        arg_types,
+        return_type,
+    } = parse(type_alias_stream).unwrap();
 
     quote! {
         #type_alias
 
         syrette::castable_to!(
             syrette::castable_factory::CastableFactory<
-                #factory_arg_types_type,
-                #factory_return_type
-            > => #trait_bound_path
+                #arg_types,
+                #return_type
+            > => #factory_interface
         );
 
         syrette::castable_to!(
             syrette::castable_factory::CastableFactory<
-                #factory_arg_types_type,
-                #factory_return_type
+                #arg_types,
+                #return_type
             > => syrette::castable_factory::AnyFactory
         );
     }