Finally figured out how I want atoms to work

orchid-api/src/error.rs

@@ -1 +1,35 @@
+use orchid_api_derive::Coding;
+
+use crate::intern::TStr;
+use crate::location::Location;
+
 pub type ProjErrId = u16;
+
+#[derive(Clone, Debug, Hash, PartialEq, Eq, Coding)]
+pub struct ProjErrLocation {
+  /// Description of the relation of this location to the error. If not used,
+  /// set to empty string
+  message: String,
+  /// Location in code where the error emerged. This is usually [Location::Gen].
+  location: Location,
+}
+
+/// Programming errors raised by extensions. At runtime these produce the
+/// equivalent of a Haskell bottom. Note that runtime errors produced by
+/// fallible operations should return an Orchid result and not a bottom.
+/// For example, file reading produces result::err when the file doesn't exist,
+/// and a bottom if the file name isn't a string.
+#[derive(Clone, Debug, Hash, PartialEq, Eq, Coding)]
+pub struct ProjErr {
+  /// General description of the kind of error.
+  description: TStr,
+  /// Specific information about the exact error, preferably containing concrete
+  /// values.
+  message: String,
+  /// Specific code fragments that have contributed to the emergence of the
+  /// error.
+  locations: Vec<ProjErrLocation>,
+}
+
+/// If this is an [`Err`] then the [`Vec`] must not be empty.
+pub type ProjResult<T> = Result<T, Vec<ProjErr>>;