very elegant extension API and parts of it used in std as POC

orchid-base/src/error.rs

@@ -0,0 +1,48 @@
+use std::sync::Arc;
+
+use orchid_api::error::{ProjErr, ProjErrLocation};
+
+use crate::interner::{deintern, Tok};
+use crate::location::Pos;
+
+/// A point of interest in resolving the error, such as the point where
+/// processing got stuck, a command that is likely to be incorrect
+#[derive(Clone)]
+pub struct ErrorPosition {
+  /// The suspected origin
+  pub position: Pos,
+  /// Any information about the role of this origin
+  pub message: Option<Arc<String>>,
+}
+impl ErrorPosition {
+  pub fn from_api(pel: &ProjErrLocation) -> Self {
+    Self {
+      message: Some(pel.message.clone()).filter(|s| !s.is_empty()),
+      position: Pos::from_api(&pel.location),
+    }
+  }
+  pub fn to_api(&self) -> ProjErrLocation {
+    ProjErrLocation {
+      message: self.message.clone().unwrap_or_default(),
+      location: self.position.to_api(),
+    }
+  }
+}
+impl From<Pos> for ErrorPosition {
+  fn from(origin: Pos) -> Self { Self { position: origin, message: None } }
+}
+
+pub struct ErrorDetails {
+  pub description: Tok<String>,
+  pub message: Arc<String>,
+  pub locations: Vec<ErrorPosition>,
+}
+impl ErrorDetails {
+  pub fn from_api(err: &ProjErr) -> Self {
+    Self {
+      description: deintern(err.description),
+      message: err.message.clone(),
+      locations: err.locations.iter().map(ErrorPosition::from_api).collect(),
+    }
+  }
+}