1 files changed, 44 insertions, 0 deletions
diff --git a/src/macros/enum_is.rs b/src/macros/enum_is.rs
new file mode 100644
index 0000000..ecada45
--- /dev/null
+++ b/src/macros/enum_is.rs
@@ -0,0 +1,44 @@
+use crate::helpers::{non_enum_error, snakify, HasStrumVariantProperties};
+use proc_macro2::TokenStream;
+use quote::{format_ident, quote};
+use syn::{Data, DeriveInput};
+
+pub fn enum_is_inner(ast: &DeriveInput) -> syn::Result<TokenStream> {
+    let variants = match &ast.data {
+        Data::Enum(v) => &v.variants,
+        _ => return Err(non_enum_error()),
+    };
+    let (impl_generics, ty_generics, where_clause) = ast.generics.split_for_impl();
+
+    let enum_name = &ast.ident;
+    let variants: Vec<_> = variants
+        .iter()
+        .filter_map(|variant| {
+            if variant.get_variant_properties().ok()?.disabled.is_some() {
+                return None;
+            }
+
+            let variant_name = &variant.ident;
+            let fn_name = format_ident!("is_{}", snakify(&variant_name.to_string()));
+            let doc_comment = format!("Returns [true] if the enum is [{}::{}] otherwise [false]", enum_name, variant_name);
+            Some(quote! {
+                #[must_use]
+                #[inline]
+                #[doc = #doc_comment]
+                pub const fn #fn_name(&self) -> bool {
+                    match self {
+                        &#enum_name::#variant_name { .. } => true,
+                        _ => false
+                    }
+                }
+            })
+        })
+        .collect();
+
+    Ok(quote! {
+        impl #impl_generics #enum_name  #ty_generics #where_clause {
+            #(#variants)*
+        }
+    }
+    .into())
+}