add README description

README.md

@@ -1,3 +1,45 @@
-# lib-rs
+# macroconf
 
-Template for rust libraries
+This library provides a macro to create configs with metadata attached to the values.
+The [miniconf](https://github.com/quartiq/miniconf) library is used to make the metadata and the values accessible.
+
+## Example
+
+```rust
+use miniconf::Tree;
+use macroconf::config;
+
+#[config]
+#[derive(Tree)]
+struct Config {
+    ordinary: i32,
+
+    #[min = 10]
+    #[max = 20]
+    clamped: u8
+
+    #[default = 42]
+    has_default: i32;
+
+    /// Doc comments are used as description
+    with_description: i32
+}
+
+/* The resulting miniconf tree looks like this:
+ * /
+ * |-ordinary
+ * |
+ * |-clamped
+ * | |-value
+ * | |-min
+ * | |-max
+ * |
+ * |-has_default
+ * | |-value
+ * | |-default
+ * |
+ * |-with_description
+ *   |-value
+ *   |-description
+ */
+```

src/lib.rs

@@ -62,7 +62,6 @@ fn generate_helper_struct(
     let mut new_type_miniconf_names = vec![];
     let mut new_type_miniconf_consts = vec![];
     let mut extra_new_checks = TokenStream2::new();
-    let mut generate_new_type = false;
     for attr in &field.attrs {
         if let Some((new_type_impl, new_check, const_ident, key)) =
             parse_min(&new_type_ident, attr, &ty)
@@ -71,7 +70,6 @@ fn generate_helper_struct(
             new_type_miniconf_consts.push(const_ident);
             new_type_miniconf_names.push(key);
             extra_new_checks.extend(new_check);
-            generate_new_type = true;
         }
         if let Some((new_type_impl, new_check, const_ident, key)) =
             parse_max(&new_type_ident, attr, &ty)
@@ -80,13 +78,11 @@ fn generate_helper_struct(
             new_type_miniconf_consts.push(const_ident);
             new_type_miniconf_names.push(key);
             extra_new_checks.extend(new_check);
-            generate_new_type = true;
         }
         if let Some((new_type_impl, const_ident, key)) = parse_default(&new_type_ident, attr, &ty) {
             new_type_impls.extend(new_type_impl);
             new_type_miniconf_consts.push(const_ident);
             new_type_miniconf_names.push(key);
-            generate_new_type = true;
         }
         if let Some((new_type_impl, const_ident, key)) = parse_description(&new_type_ident, attr) {
             new_type_impls.extend(new_type_impl);
@@ -94,7 +90,7 @@ fn generate_helper_struct(
             new_type_miniconf_names.push(key);
         }
     }
-    if !generate_new_type {
+    if new_type_miniconf_names.is_empty() {
         return None;
     }
     field.attrs.retain(|attr| {