Initial NixOS#107 work

src/problem/mod.rs

@@ -34,6 +34,8 @@ pub mod npv_161;
 pub mod npv_162;
 pub mod npv_163;
 
+pub mod npv_170;
+
 #[derive(Clone, Display, EnumFrom)]
 pub enum Problem {
     /// NPV-100: attribute is not defined but it should be defined automatically
@@ -123,6 +125,9 @@ pub enum Problem {
     NewTopLevelPackageShouldBeByNameWithCustomArgument(
         npv_163::NewTopLevelPackageShouldBeByNameWithCustomArgument,
     ),
+
+    /// NPV-170: by-name package cannot be number prefixed
+    ByNamePackegPrefixedWithNumber(npv_170::ByNamePackegPrefixedWithNumber),
 }
 
 fn indent_definition(column: usize, definition: &str) -> String {

src/problem/npv_170.rs

@@ -0,0 +1,19 @@
+use std::fmt;
+
+use derive_new::new;
+
+#[derive(Clone, new)]
+pub struct ByNamePackegPrefixedWithNumber {
+    #[new(into)]
+    attribute_name: String,
+}
+
+impl fmt::Display for ByNamePackegPrefixedWithNumber {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let Self { attribute_name } = self;
+        write!(
+            f,
+            r#"- pkgs.{attribute_name}: "Attribute names should not be number-prefixed. It is suggestet to `"`-wrap this name"#
+        )
+    }
+}