Merge pull request #39 from YushiOMOTE/require-enum-fromstr

Requires enum to implement FromStr

README.md

@@ -68,6 +68,26 @@ There are some existing crates that provide similar features but `econf` is uniq
 * Containers: `Vec`, `HashSet`, `HashMap`, `Option`, `BTreeMap`, `BTreeSet`, `BinaryHeap`, `LinkedList`, `VecDeque`, `tuple`
     * Containers are parsed as YAML format. See [the tests](https://github.com/YushiOMOTE/econf/blob/master/econf/tests/basics.rs).
 
+## Enums
+
+Since v0.3.0, econf requires enums to implement [FromStr](https://doc.rust-lang.org/std/str/trait.FromStr.html) trait. Without this implementation, your program will fail to compile. While you can write the `FromStr` implementation manually, you can alternatively use [strum](https://github.com/Peternator7/strum) crate to automatically generate it. `strum` provides several useful features, making it a generally recommended choice. See [econf/examples/strum.rs](https://github.com/YushiOMOTE/econf/tree/master/econf/examples/strum.rs) for example code.
+
+```rust
+use econf::LoadEnv;
+
+#[derive(Debug, strum::EnumString, LoadEnv)]
+#[strum(serialize_all = "kebab-case")]
+enum AuthMode {
+    ApiKey,
+    BasicAuth,
+    #[strum(ascii_case_insensitive)]
+    BearerToken,
+    #[strum(serialize = "oauth", serialize = "OAuth")]
+    OAuth,
+    JWT,
+}
+```
+
 ## Nesting
 
 Nested structs are supported.

econf-derive/src/lib.rs

@@ -113,21 +113,8 @@ fn content(name: &Ident, data: &Data) -> TokenStream2 {
                 Fields::Unit => {}
             });
 
-            let enums0 = data.variants.iter().map(|_| &name);
-            let enums1 = data.variants.iter().map(|f| &f.ident);
-            let enums2 = data.variants.iter().map(|f| &f.ident);
-
             quote! {
-                match String::default().load(path, loader).as_ref() {
-                    #(
-                        stringify!(#enums1) => #enums0::#enums2,
-                    )*
-                    "" => self,
-                    x => {
-                        error!("econf: couldn't find variant: {}", x);
-                        self
-                    }
-                }
+                loader.load_from_str(self, path)
             }
         }
         Data::Union(_) => unimplemented!("Unions are not supported"),

econf/Cargo.toml

@@ -19,3 +19,4 @@ humantime = "2.1"
 
 [dev-dependencies]
 simple_logger = "5.0"
+strum = { version = "0.26", features = ["derive"] }

econf/examples/alltypes.rs

@@ -2,7 +2,7 @@ use econf::LoadEnv;
 use log::*;
 use std::collections::{HashMap, HashSet};
 
-#[derive(Debug, LoadEnv)]
+#[derive(Debug, strum::EnumString, LoadEnv)]
 enum X {
     V1,
     V2,

econf/examples/sample.rs

@@ -2,7 +2,7 @@ use econf::LoadEnv;
 use log::*;
 use std::collections::HashMap;
 
-#[derive(Debug, LoadEnv)]
+#[derive(Debug, strum::EnumString, LoadEnv)]
 enum X {
     V1,
     V2,

econf/examples/strum.rs

@@ -0,0 +1,34 @@
+use econf::LoadEnv;
+
+#[derive(Debug, strum::EnumString, LoadEnv)]
+#[strum(serialize_all = "kebab-case")]
+enum AuthMode {
+    ApiKey,
+    BasicAuth,
+    #[strum(ascii_case_insensitive)]
+    BearerToken,
+    #[strum(serialize = "oauth", serialize = "OAuth")]
+    OAuth,
+    JWT,
+}
+
+#[derive(Debug, LoadEnv)]
+struct Config {
+    auth_mode: AuthMode,
+    data: String,
+    passwd: String,
+}
+
+fn main() {
+    simple_logger::init().unwrap();
+
+    let c = Config {
+        auth_mode: AuthMode::ApiKey,
+        data: "foo".into(),
+        passwd: "bar".into(),
+    };
+    println!("Before loading env: {c:?}");
+
+    let c = econf::load(c, "app");
+    println!("After loading env: {c:?}");
+}

econf/src/lib.rs

@@ -66,6 +66,26 @@
 //! * Containers: `Vec`, `HashSet`, `HashMap`, `Option`, `BTreeMap`, `BTreeSet`, `BinaryHeap`, `LinkedList`, `VecDeque`, `tuple`
 //!     * Containers are parsed as YAML format. See [the tests](https://github.com/YushiOMOTE/econf/blob/master/econf/tests/basics.rs).
 //!
+//! # Enums
+//!
+//! Since v0.3.0, econf requires enums to implement [FromStr](https://doc.rust-lang.org/std/str/trait.FromStr.html) trait. Without this implementation, your program will fail to compile. While you can write the `FromStr` implementation manually, you can alternatively use [strum](https://github.com/Peternator7/strum) crate to automatically generate it. `strum` provides several useful features, making it a generally recommended choice. See [econf/examples/strum.rs](https://github.com/YushiOMOTE/econf/tree/master/econf/examples/strum.rs) for example code.
+//!
+//! ```
+//! use econf::LoadEnv;
+//!
+//! #[derive(Debug, strum::EnumString, LoadEnv)]
+//! #[strum(serialize_all = "kebab-case")]
+//! enum AuthMode {
+//!     ApiKey,
+//!     BasicAuth,
+//!     #[strum(ascii_case_insensitive)]
+//!     BearerToken,
+//!     #[strum(serialize = "oauth", serialize = "OAuth")]
+//!     OAuth,
+//!     JWT,
+//! }
+//! ```
+//!
 //! # Nesting
 //!
 //! Nested structs are supported.