Generate everything strum does myself (no duplicate prop names)

crates/xml/derive/src/attrs.rs

@@ -22,7 +22,7 @@ pub struct VariantAttrs {
 #[darling(attributes(xml))]
 pub struct EnumAttrs {
     pub untagged: Flag,
-    pub unit_variants_name: Option<String>,
+    pub unit_variants_ident: Option<syn::Ident>,
 }
 
 #[derive(Default, FromDeriveInput, Clone)]

crates/xml/derive/src/xml_enum.rs

@@ -2,7 +2,6 @@ use super::{attrs::EnumAttrs, Variant};
 use crate::attrs::VariantAttrs;
 use core::panic;
 use darling::{FromDeriveInput, FromVariant};
-use proc_macro2::Span;
 use quote::quote;
 use syn::{DataEnum, DeriveInput};
 
@@ -245,11 +244,11 @@ impl Enum {
         if self.attrs.untagged.is_present() {
             panic!("EnumUnitVariants not implemented for untagged enums");
         }
-        let unit_enum_ident = if let Some(name) = &self.attrs.unit_variants_name {
-            syn::Ident::new(name, Span::call_site())
-        } else {
-            panic!("unit_variants_name not set");
-        };
+        let unit_enum_ident = self
+            .attrs
+            .unit_variants_ident
+            .as_ref()
+            .expect("unit_variants_ident no set");
 
         let tagged_variants: Vec<_> = self
             .variants
@@ -287,8 +286,15 @@ impl Enum {
             quote! { #ident::#variant_ident { .. } => #unit_enum_ident::#variant_ident }
         });
 
+        let str_to_unit_branches = tagged_variants.iter().map(|variant| {
+            let variant_ident = &variant.variant.ident;
+            let b_xml_name = variant.xml_name().value();
+            let xml_name = String::from_utf8_lossy(&b_xml_name);
+            quote! { #xml_name => Ok(#unit_enum_ident::#variant_ident) }
+        });
+
         quote! {
-            enum #unit_enum_ident {
+            pub enum #unit_enum_ident {
                 #(#variant_idents),*
             }
 
@@ -307,6 +313,17 @@ impl Enum {
                     }
                 }
             }
+
+            impl ::std::str::FromStr for #unit_enum_ident {
+                type Err = ::rustical_xml::FromStrError;
+
+                fn from_str(val: &str) -> Result<Self, Self::Err> {
+                    match val {
+                        #(#str_to_unit_branches),*,
+                        _ => Err(::rustical_xml::FromStrError)
+                    }
+                }
+            }
         }
     }
 }

crates/xml/src/lib.rs

@@ -24,6 +24,9 @@ pub trait XmlRootTag {
     fn root_ns_prefixes() -> HashMap<Namespace<'static>, &'static [u8]>;
 }
 
+#[derive(Debug)]
+pub struct FromStrError;
+
 pub trait EnumVariants {
     const TAGGED_VARIANTS: &'static [(Option<Namespace<'static>>, &'static str)];
 

crates/xml/tests/enum_variants.rs

@@ -1,3 +1,5 @@
+use std::str::FromStr;
+
 use quick_xml::name::Namespace;
 use rustical_xml::EnumVariants;
 use xml_derive::EnumUnitVariants;
@@ -16,7 +18,7 @@ enum ExtensionProp {
 }
 
 #[derive(EnumVariants, EnumUnitVariants)]
-#[xml(unit_variants_name = "CalendarPropName")]
+#[xml(unit_variants_ident = "CalendarPropName")]
 enum CalendarProp {
     // WebDAV (RFC 2518)
     #[xml(ns = "NS_DAV")]
@@ -73,4 +75,7 @@ fn test_enum_unit_variants() {
     let propname: CalendarPropName = CalendarProp::Displayname(None).into();
     let displayname: (Option<Namespace>, &str) = propname.into();
     assert_eq!(displayname, (Some(NS_DAV), "displayname"));
+
+    let propname: CalendarPropName = FromStr::from_str("displayname").unwrap();
+    assert_eq!(displayname, (Some(NS_DAV), "displayname"));
 }