Prefix suffix (#1)

Add support for custom string representation.

Cargo.toml

@@ -9,6 +9,7 @@ license = "MIT OR Apache-2.0"
 homepage = "https://github.com/Yag000/enum_stringify"
 repository = "https://github.com/Yag000/enum_stringify"
 documentation = "https://docs.rs/enum_stringify"
+keywords = ["enum", "string", "derive", "macro"]
 
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
@@ -19,3 +20,7 @@ proc-macro = true
 [dependencies]
 quote = "1.0.33"
 syn = "2.0.32"
+
+[dev-dependencies]
+serde = { version = "1.0.130", features = ["derive"] }
+

README.md

@@ -26,6 +26,26 @@ fn main() {
 }
 ```
 
+### Custom string representation
+
+You can customize the string representation of the enum by adding rpefixes or/and suffixes to the
+variants.
+
+```rust
+use enum_stringify::EnumStringify;
+
+#[derive(EnumStringify)]
+#[enum_stringify(prefix = "MyPrefix", suffix = "MySuffix")]
+enum MyEnum {
+    Variant1,
+    Variant2,
+    Variant3,
+}
+```
+
+In this case the string representation of `MyEnum::Variant1` will be `MyPrefixVariant1MySuffix`(and
+so on for the other variants).
+
 ## Documentation and installation
 
 See [docs.rs](https://docs.rs/enum-stringify) for documentation.

src/attributes.rs

@@ -0,0 +1,100 @@
+use syn::{DeriveInput, Meta};
+
+pub(crate) enum Case {
+    Camel,
+    Snake,
+    None,
+}
+
+pub(crate) struct Attributes {
+    pub(crate) case: Option<Case>,
+    pub(crate) prefix: Option<String>,
+    pub(crate) suffix: Option<String>,
+}
+
+impl Attributes {
+    pub(crate) fn new(ast: &DeriveInput) -> Self {
+        let mut new = Self {
+            case: None,
+            prefix: None,
+            suffix: None,
+        };
+
+        ast.attrs.iter().for_each(|attr| match &attr.meta {
+            Meta::Path(_) => {
+                panic!("Unexpected argument");
+            }
+            Meta::List(list) => {
+                let path = list
+                    .path
+                    .segments
+                    .iter()
+                    .map(|s| s.ident.to_string())
+                    .collect::<Vec<_>>();
+
+                if path == vec!["enum_stringify"] {
+                    let mut tokens = list.tokens.clone().into_iter();
+
+                    while let Some(attribute_type) = tokens.next() {
+                        let attribute_type = attribute_type.to_string();
+
+                        if tokens.next().expect("type must be specified").to_string() != "=" {
+                            panic!("too many arguments");
+                        }
+                        let value = tokens.next().expect("value must be specified").to_string();
+
+                        match attribute_type.as_str() {
+                            "case" => {
+                                let case = match value.as_str() {
+                                    "camel" => Case::Camel,
+                                    "snake" => Case::Snake,
+                                    _ => Case::None,
+                                };
+                                new.case = Some(case);
+                            }
+                            "prefix" => {
+                                new.prefix = Some(value);
+                            }
+                            "suffix" => {
+                                new.suffix = Some(value);
+                            }
+                            _ => {
+                                panic!("Attribute not supported");
+                            }
+                        }
+
+                        if let Some(comma_separator) = tokens.next() {
+                            if comma_separator.to_string() != "," {
+                                panic!("Expected a commaseparated attribute list");
+                            }
+                        }
+                    }
+                }
+            }
+            Meta::NameValue(_) => {
+                panic!("Unexpected argument");
+            }
+        });
+
+        new
+    }
+
+    pub(crate) fn apply(&self, names: &Vec<&syn::Ident>) -> Vec<syn::Ident> {
+        let mut new_names = Vec::new();
+        for name in names {
+            let mut new_name = String::new();
+            if let Some(prefix) = &self.prefix {
+                new_name.push_str(prefix);
+            }
+
+            // Add here case logic
+            new_name.push_str(&name.to_string());
+
+            if let Some(suffix) = &self.suffix {
+                new_name.push_str(suffix);
+            }
+            new_names.push(syn::Ident::new(&new_name, name.span()));
+        }
+        new_names
+    }
+}

src/lib.rs

@@ -3,8 +3,12 @@
 //! Derive [`std::fmt::Display`], [`std::str::FromStr`], [`TryFrom<&str>`] and
 //! [`TryFrom<String>`] with a simple derive macro: [`EnumStringify`].
 
+use attributes::Attributes;
 use proc_macro::TokenStream;
 use quote::quote;
+use syn::{parse_macro_input, DeriveInput};
+
+mod attributes;
 
 /// Derive [`std::fmt::Display`], [`std::str::FromStr`], [`TryFrom<&str>`] and
 /// [`TryFrom<String>`] for an enum.
@@ -33,6 +37,29 @@ use quote::quote;
 /// assert!(Numbers::try_from("Three").is_err());
 /// ```
 ///
+/// # Prefix and suffix
+///
+/// You can add a prefix and/or a suffix to the string representation of the
+/// enum variants.
+///
+/// ```
+/// use enum_stringify::EnumStringify;
+/// use std::str::FromStr;
+///
+/// #[derive(EnumStringify, Debug, PartialEq)]
+/// #[enum_stringify(prefix = MyPrefix, suffix = MySuffix)]
+/// enum Numbers {
+///   One,
+///   Two,
+/// }
+///
+/// assert_eq!(Numbers::One.to_string(), "MyPrefixOneMySuffix");
+/// assert_eq!(Numbers::Two.to_string(), "MyPrefixTwoMySuffix");
+///
+/// assert_eq!(Numbers::try_from("MyPrefixOneMySuffix").unwrap(), Numbers::One);
+/// assert_eq!(Numbers::try_from("MyPrefixTwoMySuffix").unwrap(), Numbers::Two);
+/// ```
+///
 /// # Details
 ///
 /// The implementations of the above traits corresponds to this:
@@ -80,36 +107,43 @@ use quote::quote;
 ///     }
 /// }
 /// ```
-#[proc_macro_derive(EnumStringify)]
+#[proc_macro_derive(EnumStringify, attributes(enum_stringify))]
 pub fn enum_stringify(input: TokenStream) -> TokenStream {
-    let ast = syn::parse(input).unwrap();
+    let ast = parse_macro_input!(input as DeriveInput);
+
     impl_enum_to_string(&ast)
 }
 
 fn impl_enum_to_string(ast: &syn::DeriveInput) -> TokenStream {
+    let attributes = Attributes::new(ast);
     let name = &ast.ident;
     let variants = match ast.data {
         syn::Data::Enum(ref e) => &e.variants,
         _ => panic!("EnumToString only works with Enums"),
     };
 
-    let names = variants.iter().map(|v| &v.ident).collect::<Vec<_>>();
+    let identifiers = variants.iter().map(|v| &v.ident).collect::<Vec<_>>();
+    let names = attributes.apply(&identifiers);
 
-    let mut gen = impl_display(name, &names);
-    gen.extend(impl_from_str(name, &names));
+    let mut gen = impl_display(name, &identifiers, &names);
+    gen.extend(impl_from_str(name, &identifiers, &names));
     gen.extend(impl_from_string(name));
     gen.extend(impl_from_str_trait(name));
 
     gen
 }
 
 /// Implementation of [`std::fmt::Display`].
-fn impl_display(name: &syn::Ident, names: &Vec<&syn::Ident>) -> TokenStream {
+fn impl_display(
+    name: &syn::Ident,
+    identifiers: &Vec<&syn::Ident>,
+    names: &Vec<syn::Ident>,
+) -> TokenStream {
     let gen = quote! {
         impl std::fmt::Display for #name {
             fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
                 match self {
-                    #(Self::#names => write!(f, stringify!(#names))),*
+                    #(Self::#identifiers=> write!(f, stringify!(#names))),*
                 }
             }
         }
@@ -119,14 +153,18 @@ fn impl_display(name: &syn::Ident, names: &Vec<&syn::Ident>) -> TokenStream {
 }
 
 /// Implementation of [`TryFrom<&str>`].
-fn impl_from_str(name: &syn::Ident, names: &Vec<&syn::Ident>) -> TokenStream {
+fn impl_from_str(
+    name: &syn::Ident,
+    identifiers: &Vec<&syn::Ident>,
+    names: &Vec<syn::Ident>,
+) -> TokenStream {
     let gen = quote! {
         impl TryFrom<&str> for #name {
             type Error = ();
 
             fn try_from(s: &str) -> Result<Self, Self::Error> {
                 match s {
-                    #(stringify!(#names) => Ok(Self::#names),)*
+                    #(stringify!(#names) => Ok(Self::#identifiers),)*
                     _ => Err(()),
                 }
             }

tests/attributes.rs

@@ -0,0 +1,90 @@
+use std::str::FromStr;
+
+#[derive(Debug, PartialEq, enum_stringify::EnumStringify)]
+#[enum_stringify(suffix = Suff)]
+enum Number1 {
+    Zero,
+    One,
+    Two,
+}
+
+#[test]
+fn test_suffix_to_string() {
+    assert_eq!(Number1::Zero.to_string(), "ZeroSuff");
+    assert_eq!(Number1::One.to_string(), "OneSuff");
+    assert_eq!(Number1::Two.to_string(), "TwoSuff");
+}
+#[test]
+fn test_suffix_from_str() {
+    assert_eq!(Number1::from_str("ZeroSuff"), Ok(Number1::Zero));
+    assert_eq!(Number1::from_str("OneSuff"), Ok(Number1::One));
+    assert_eq!(Number1::from_str("TwoSuff"), Ok(Number1::Two));
+}
+
+#[derive(Debug, PartialEq, enum_stringify::EnumStringify)]
+#[enum_stringify(prefix = Pref)]
+enum Number2 {
+    Zero,
+    One,
+    Two,
+}
+
+#[test]
+fn test_prefix_to_string() {
+    assert_eq!(Number2::Zero.to_string(), "PrefZero");
+    assert_eq!(Number2::One.to_string(), "PrefOne");
+    assert_eq!(Number2::Two.to_string(), "PrefTwo");
+}
+
+#[test]
+fn test_prefix_from_str() {
+    assert_eq!(Number2::from_str("PrefZero"), Ok(Number2::Zero));
+    assert_eq!(Number2::from_str("PrefOne"), Ok(Number2::One));
+    assert_eq!(Number2::from_str("PrefTwo"), Ok(Number2::Two));
+}
+
+#[derive(Debug, PartialEq, enum_stringify::EnumStringify)]
+#[enum_stringify(prefix = Pref, suffix = Suff)]
+enum Number3 {
+    Zero,
+    One,
+    Two,
+}
+
+#[test]
+fn test_prefix_suffix_to_string() {
+    assert_eq!(Number3::Zero.to_string(), "PrefZeroSuff");
+    assert_eq!(Number3::One.to_string(), "PrefOneSuff");
+    assert_eq!(Number3::Two.to_string(), "PrefTwoSuff");
+}
+
+#[test]
+fn test_prefix_suffix_from_str() {
+    assert_eq!(Number3::from_str("PrefZeroSuff"), Ok(Number3::Zero));
+    assert_eq!(Number3::from_str("PrefOneSuff"), Ok(Number3::One));
+    assert_eq!(Number3::from_str("PrefTwoSuff"), Ok(Number3::Two));
+}
+
+// Testing commutativity of prefix and suffix
+
+#[derive(Debug, PartialEq, enum_stringify::EnumStringify)]
+#[enum_stringify(suffix = Suff, prefix = Pref)]
+enum Number4 {
+    Zero,
+    One,
+    Two,
+}
+
+#[test]
+fn test_suffix_prefix_to_string() {
+    assert_eq!(Number4::Zero.to_string(), "PrefZeroSuff");
+    assert_eq!(Number4::One.to_string(), "PrefOneSuff");
+    assert_eq!(Number4::Two.to_string(), "PrefTwoSuff");
+}
+
+#[test]
+fn test_suffix_prefix_from_str() {
+    assert_eq!(Number4::from_str("PrefZeroSuff"), Ok(Number4::Zero));
+    assert_eq!(Number4::from_str("PrefOneSuff"), Ok(Number4::One));
+    assert_eq!(Number4::from_str("PrefTwoSuff"), Ok(Number4::Two));
+}