feat: add injecting singletons into constructors

1 files changed, 40 insertions, 0 deletions

diff --git a/macros/src/dependency_type.rs b/macros/src/dependency_type.rs
new file mode 100644
index 0000000..35f810e
--- /dev/null
+++ b/macros/src/dependency_type.rs
@@ -0,0 +1,40 @@
+use proc_macro2::Ident;
+use syn::{GenericArgument, PathArguments, Type, TypePath};
+
+pub struct DependencyType
+{
+    pub interface: Type,
+    pub ptr: Ident,
+}
+
+impl DependencyType
+{
+    pub fn from_type_path(type_path: &TypePath) -> Option<Self>
+    {
+        // Assume the type path has a last segment.
+        let last_path_segment = type_path.path.segments.last().unwrap();
+
+        let ptr = &last_path_segment.ident;
+
+        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 TransientPtr,
+                // SingletonPtr 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(Self {
+                        interface: first_generic_arg_type.clone(),
+                        ptr: ptr.clone(),
+                    }),
+                    &_ => None,
+                }
+            }
+            &_ => None,
+        }
+    }
+}