use rstest

Cargo.toml

@@ -33,3 +33,5 @@ darling = "0.20"
 [dev-dependencies]
 miniconf = { version = "0.13", features = ["json-core"] }
 serde = "1.0"
+rstest = "0.22"
+serde-json-core = "0.5.1"

src/parser.rs

@@ -1,5 +1,7 @@
 #![allow(clippy::option_if_let_else)]
 
+use std::convert::identity;
+
 use convert_case::{Case, Casing};
 use darling::{
     ast::{self, Data},
@@ -8,7 +10,7 @@ use darling::{
 };
 use proc_macro2::{Span, TokenStream};
 use quote::{format_ident, quote};
-use syn::parse_quote;
+use syn::{parse_quote, spanned::Spanned};
 
 #[derive(Debug, FromField)]
 #[darling(attributes(config))]
@@ -21,6 +23,9 @@ pub struct ConfigField {
     min: Option<Override<syn::Expr>>,
     max: Option<Override<syn::Expr>>,
     default: Option<Override<syn::Expr>>,
+    typ: Option<syn::Type>,
+    get: Option<syn::Path>,
+    set: Option<syn::Path>,
     #[darling(skip)]
     description: Option<syn::Expr>,
     #[darling(skip)]
@@ -88,7 +93,8 @@ impl ConfigField {
     }
 
     pub(crate) fn has_custom_limits(&self) -> bool {
-        !((self.min.is_none() || self.min == Some(Override::Inherit))
+        self.typ.is_none()
+            && !((self.min.is_none() || self.min == Some(Override::Inherit))
                 && (self.max.is_none() || self.max == Some(Override::Inherit)))
     }
 
@@ -148,7 +154,7 @@ impl ConfigField {
     pub(crate) fn helper_default(&self) -> Option<TokenStream> {
         self.default.as_ref().map(|default| {
             let ident = self.helper_ident();
-            let default_default = parse_quote!(default::Default());
+            let default_default = parse_quote!(::core::default::Default::default());
             let default = default.as_ref().unwrap_or(&default_default);
             quote! {
                 impl ::core::default::Default for #ident {
@@ -209,7 +215,7 @@ impl ConfigField {
         macro_rules! field_to_key {
             ($field: ident, $default: expr) => {
                 self.$field.as_ref().map(|value| {
-                    let ty = &self.ty;
+                    let ty = self.typ.as_ref().unwrap_or(&self.ty);
                     (stringify!($field),
                     value.clone().explicit().map(|val| {
                         parse_quote!({
@@ -288,6 +294,7 @@ impl ConfigField {
             .helper_keys()
             .iter()
             .enumerate()
+            .skip(1)
             .map(|(i, (_, expr))| {
                 quote! {
                     #i => ::serde::Serialize::serialize(&#expr, ser).map_err(|err| ::miniconf::Error::Inner(0, err)),
@@ -295,6 +302,10 @@ impl ConfigField {
             })
             .collect::<Vec<_>>();
         let ident = self.helper_ident();
+        let get = self
+            .get
+            .as_ref()
+            .map_or_else(|| quote! {self}, |getter| quote! {#getter(&self.0)});
         quote! {
             impl ::miniconf::TreeSerialize<1> for #ident {
                 fn serialize_by_key<K, S>(
@@ -307,13 +318,14 @@ impl ConfigField {
                     S: ::serde::Serializer,
                 {
                     let ::core::result::Result::Ok(key) = keys.next::<Self>() else {
-                        return ::serde::Serialize::serialize(&self, ser).map_err(|err| ::miniconf::Error::Inner(1, err)).map(|_| 1);
+                        return ::serde::Serialize::serialize(&#get, ser).map_err(|err| ::miniconf::Error::Inner(0, err)).map(|_| 0);
                     };
-                    let index = ::miniconf::Key::find::<Self>(&key).ok_or(::miniconf::Traversal::NotFound(1))?;
+                    let index = ::miniconf::Key::find::<Self>(&key).ok_or(::miniconf::Traversal::NotFound(0))?;
                     if !keys.finalize() {
-                        return ::core::result::Result::Err(::miniconf::Traversal::TooLong(1).into());
+                        return ::core::result::Result::Err(::miniconf::Traversal::TooLong(0).into());
                     }
                     match index {
+                        0 => ::serde::Serialize::serialize(&#get, ser).map_err(|err| ::miniconf::Error::Inner(0, err)),
                         #(#matches)*
                         _ => unreachable!(),
                     }?;
@@ -326,6 +338,14 @@ impl ConfigField {
     pub(crate) fn helper_tree_deserialize(&self) -> TokenStream {
         let ident = self.helper_ident();
         let num_keys = self.helper_keys().len();
+        let set = self.set.as_ref().map_or_else(
+            || quote!((|val| {*self = val; core::result::Result::<_, ::miniconf::Traversal>::Ok(())})),
+            |set| quote!((|val| #set(&mut self.0, val).map_err(|e| ::miniconf::Traversal::Invalid(0, e)))),
+        );
+        let typ = self
+            .typ
+            .as_ref()
+            .map_or_else(|| quote!(Self), |typ| quote!(#typ));
         quote! {
             impl<'de> ::miniconf::TreeDeserialize<'de, 1> for #ident {
                 fn deserialize_by_key<K, D>(
@@ -338,7 +358,7 @@ impl ConfigField {
                     D: ::serde::Deserializer<'de>,
                 {
                     let ::core::result::Result::Ok(key) = keys.next::<Self>() else {
-                        *self = <Self as ::serde::Deserialize>::deserialize(de).map_err(|err| ::miniconf::Error::Inner(0, err))?;
+                        #set(<#typ as ::serde::Deserialize>::deserialize(de).map_err(|err| ::miniconf::Error::Inner(0, err))?)?;
                         return ::core::result::Result::Ok(0);
                     };
                     let index = ::miniconf::Key::find::<Self>(&key).ok_or(::miniconf::Traversal::NotFound(1))?;
@@ -347,7 +367,7 @@ impl ConfigField {
                     }
                     match index {
                         0 => {
-                            *self = <Self as ::serde::Deserialize>::deserialize(de).map_err(|err| ::miniconf::Error::Inner(0, err))?;
+                            #set(<#typ as ::serde::Deserialize>::deserialize(de).map_err(|err| ::miniconf::Error::Inner(0, err))?)?;
                             Ok(0)
                         }
                         ,
@@ -436,6 +456,26 @@ impl Config {
                     parse_quote!(#description)
                 });
             field.parent_ident = Some(ident.clone());
+            let get_set_typ = [
+                field.typ.is_some(),
+                field.get.is_some(),
+                field.set.is_some(),
+            ];
+            if get_set_typ.iter().copied().any(identity) && !get_set_typ.into_iter().all(identity) {
+                return Err(
+                    Error::custom("need all or none of 'typ', 'get', 'set'").with_span(
+                        &field.typ.as_ref().map_or_else(
+                            || {
+                                field.get.as_ref().map_or_else(
+                                    || field.set.as_ref().unwrap().span(),
+                                    Spanned::span,
+                                )
+                            },
+                            Spanned::span,
+                        ),
+                    ),
+                );
+            }
         }
         Ok(config)
     }

tests/get_set.rs

@@ -0,0 +1,54 @@
+use std::{cell::Cell, str::from_utf8};
+
+use macroconf::config;
+use miniconf::JsonCoreSlash;
+
+fn set_cell<const MIN: i32, const MAX: i32>(
+    cell: &Cell<i32>,
+    val: i32,
+) -> Result<(), &'static str> {
+    if (MIN..=MAX).contains(&val) {
+        cell.set(val);
+        Ok(())
+    } else {
+        Err("value out of bounds")
+    }
+}
+
+#[config]
+struct Config {
+    #[config(
+        min = "-128",
+        max = "128",
+        default,
+        typ = "i32",
+        get = "Cell::get",
+        set = "set_cell::<-128,128>"
+    )]
+    field: Cell<i32>,
+}
+
+#[test]
+fn get() {
+    let mut buffer = [0u8; 32];
+    let config = Config {
+        field: __ConfigField::new(Cell::new(42)),
+    };
+    let len = config.get_json("/field", &mut buffer).unwrap();
+    assert_eq!(from_utf8(&buffer[..len]), Ok("42"));
+}
+
+#[test]
+fn set() {
+    let mut config = Config {
+        field: __ConfigField::new(Cell::new(42)),
+    };
+    config.set_json("/field", b"-32").unwrap();
+    assert_eq!(config.field.get(), -32);
+    config
+        .set_json("/field", b"256")
+        .expect_err("result not checked");
+    config
+        .set_json("/field", b"-256")
+        .expect_err("result not checked");
+}

tests/simple.rs

@@ -7,6 +7,7 @@ use miniconf::{
     Traversal::{Access, TooLong},
     Tree, TreeKey,
 };
+use rstest::*;
 use serde::{Deserialize, Serialize};
 
 #[config]
@@ -30,27 +31,39 @@ struct Config {
     sub_config: SubConfig,
 }
 
-#[test]
-fn keys() {
-    for (id, field) in ["skipped", "min", "max", "default", "description"]
-        .into_iter()
-        .enumerate()
-    {
+#[rstest]
+#[case(0, ["skipped"])]
+#[case(1, ["min"])]
+#[case(2, ["max"])]
+#[case(3, ["default"])]
+#[case(4, ["description"])]
+fn key<const N: usize>(#[case] id: usize, #[case] field: [&str; N]) {
     assert_eq!(
-            SubConfig::traverse_by_key([field].into_keys(), |index, name, _len| {
-                assert_eq!((id, Some(field)), (index, name));
+        SubConfig::traverse_by_key(field.into_keys(), |index, name, _len| {
+            assert_eq!((id, Some(field[field.len() - 1])), (index, name));
             Ok::<_, ()>(())
         }),
         Ok(1)
     );
 }
-}
 
-#[test]
-fn sub_keys() {
+#[rstest]
+#[case(["skipped", "value"], Err(Traversal(TooLong(1))))]
+#[case(["min", "value"], Ok(2))]
+#[case(["max", "value"], Ok(2))]
+#[case(["default", "value"], Ok(2))]
+#[case(["description", "value"], Ok(2))]
+#[case(["min", "min"], Ok(2))]
+#[case(["max", "max"], Ok(2))]
+#[case(["default", "default"], Ok(2))]
+#[case(["description", "description"], Ok(2))]
+fn sub_keys<const N: usize>(
+    #[case] fields: [&str; N],
+    #[case] expected: Result<usize, miniconf::Error<()>>,
+) {
     assert_eq!(
-        SubConfig::traverse_by_key(["skipped", "value"].into_keys(), |_, _, _| Ok::<_, ()>(())),
-        Err(Traversal(TooLong(1)))
+        SubConfig::traverse_by_key(fields.into_keys(), |_, _, _| Ok::<_, ()>(())),
+        expected
     );
     assert_eq!(
         SubConfig::traverse_by_key(["skipped"].into_keys(), |_, _, _| Ok::<_, ()>(())),
@@ -68,39 +81,59 @@ fn sub_keys() {
     }
 }
 
-#[test]
-fn serialize() {
-    let mut buffer = [0u8; 32];
-    let config = SubConfig {
+#[fixture]
+#[once]
+fn sub_config() -> SubConfig {
+    SubConfig {
         skipped: 1,
         min: __SubConfigMin::new(2),
         max: __SubConfigMax::new(3),
         default: __SubConfigDefault::new(4),
         description: __SubConfigDescription::new(5),
-    };
-
-    for (input, output) in [
-        ("/skipped", "1"),
-        ("/min", "2"),
-        ("/min/value", "2"),
-        ("/min/min", "-2147483648"),
-        ("/max", "3"),
-        ("/max/value", "3"),
-        ("/max/max", "2147483647"),
-        ("/default", "4"),
-        ("/default/value", "4"),
-        ("/default/default", "0"),
-        ("/description", "5"),
-        ("/description/value", "5"),
-        ("/description/description", "\"This is a description\""),
-    ] {
-        let len = config.get_json(input, &mut buffer).unwrap();
-        assert_eq!(from_utf8(&buffer[..len]), Ok(output));
     }
 }
 
-#[test]
-fn deserialize() {
+#[rstest]
+#[case("/skipped", "1")]
+#[case("/min", "2")]
+#[case("/min/value", "2")]
+#[case("/min/min", "-2147483648")]
+#[case("/max", "3")]
+#[case("/max/value", "3")]
+#[case("/max/max", "2147483647")]
+#[case("/default", "4")]
+#[case("/default/value", "4")]
+#[case("/default/default", "0")]
+#[case("/description", "5")]
+#[case("/description/value", "5")]
+#[case("/description/description", "\"This is a description\"")]
+fn serialize(sub_config: &SubConfig, #[case] path: &str, #[case] expected: &str) {
+    let mut buffer = [0u8; 32];
+    let len = sub_config.get_json(path, &mut buffer).unwrap();
+    assert_eq!(from_utf8(&buffer[..len]), Ok(expected));
+}
+
+#[rstest]
+#[case("/skipped", Ok(2))]
+#[case("/min", Ok(2))]
+#[case("/min/value", Ok(2))]
+#[case("/max", Ok(2))]
+#[case("/max/value", Ok(2))]
+#[case("/default", Ok(2))]
+#[case("/default/value", Ok(2))]
+#[case("/description", Ok(2))]
+#[case("/description/value", Ok(2))]
+#[case("/min/min", Err(Traversal(Access(1, "Cannot write limits"))))]
+#[case("/max/max", Err(Traversal(Access(1, "Cannot write limits"))))]
+#[case("/default/default", Err(Traversal(Access(1, "Cannot write limits"))))]
+#[case(
+    "/description/description",
+    Err(Traversal(Access(1, "Cannot write limits")))
+)]
+fn deserialize(
+    #[case] path: &str,
+    #[case] expected: Result<usize, miniconf::Error<serde_json_core::de::Error>>,
+) {
     let mut config = SubConfig {
         skipped: 0,
         min: __SubConfigMin::new(0),
@@ -109,34 +142,12 @@ fn deserialize() {
         description: __SubConfigDescription::new(0),
     };
 
-    for input in [
-        "/skipped",
-        "/min",
-        "/min/value",
-        "/max",
-        "/max/value",
-        "/default",
-        "/default/value",
-        "/description",
-        "/description/value",
-    ] {
-        let res = config.set_json(input, b"10");
-        assert_eq!(res, Ok(2));
-    }
-
-    for input in [
-        "/min/min",
-        "/max/max",
-        "/default/default",
-        "/description/description",
-    ] {
-        let res = config.set_json(input, b"10");
-        assert_eq!(res, Err(Traversal(Access(1, "Cannot write limits"))));
-    }
+    let res = config.set_json(path, b"10");
+    assert_eq!(res, expected);
 }
 
 #[test]
-fn subconfig() {
+fn config_paths() {
     let control = vec![
         "/sub_config/skipped".to_owned(),
         "/sub_config/min/value".to_owned(),