From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 9 Jan 2023 18:56:40 +0000 (+0000)
Subject: Config inspection: Introduce InspectableConfig trait
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=6213d1610ddc72002b2603f0fab20e66fa124b8d;p=hippotat.git

Config inspection: Introduce InspectableConfig trait

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/macros/macros.rs b/macros/macros.rs
index b030756..341edb2 100644
--- a/macros/macros.rs
+++ b/macros/macros.rs
@@ -169,16 +169,18 @@ pub fn resolve(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
   let global = syn::Ident::new(&format!("{}Global", top_ident),
                                top_ident.span());
 
-  let mk_inspects = |inspects: Vec<_>| quote! {
-    pub fn inspect_key(&self, field: &'_ str)
-                       -> Option<&dyn InspectableConfigValue> {
-      Some(match field {
-        #( #inspects )*
-        _ => return None,
-      })
+  let mk_inspects = |self_, inspects: Vec<_>| quote! {
+    impl InspectableConfig for #self_ {
+      fn inspect_key(&self, field: &'_ str)
+                     -> Option<&dyn InspectableConfigValue> {
+        Some(match field {
+          #( #inspects )*
+          _ => return None,
+        })
+      }
     }
   };
-  let g_inspects = mk_inspects(g_inspects);
+  let g_inspects = mk_inspects(&global, g_inspects);
 
   let output = quote! {
     impl #target {
@@ -203,9 +205,9 @@ pub fn resolve(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
       pub fn from(l: &[#top_ident]) -> #global { #global {
         #( #global_assignments )*
       } }
-
-      #g_inspects
     }
+
+    #g_inspects
   };
 
   //eprintln!("{}", &output);
diff --git a/src/config.rs b/src/config.rs
index b659ceb..7cc9adf 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -90,6 +90,11 @@ pub struct Opts {
   pub extra_config: Vec<PathBuf>,
 }
 
+pub trait InspectableConfig {
+  fn inspect_key(&self, field: &'_ str)
+                 -> Option<&dyn InspectableConfigValue>;
+}
+
 pub trait InspectableConfigValue {
   fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result;
 }
diff --git a/src/prelude.rs b/src/prelude.rs
index 2570fcb..e38c3d5 100644
--- a/src/prelude.rs
+++ b/src/prelude.rs
@@ -55,7 +55,8 @@ pub use eyre::eyre as anyhow;
 pub use eyre::WrapErr;
 pub use eyre::Error as AE;
 
-pub use crate::config::{self, InspectableConfigValue, InstanceConfig};
+pub use crate::config::{self, InstanceConfig};
+pub use crate::config::{InspectableConfig, InspectableConfigValue};
 pub use crate::config::{DisplayInspectable, U32Ext as _};
 pub use crate::impl_inspectable_config_value;
 pub use crate::ini;