Feature fields: a type for each role (Expr, BodyName, FacePick…) (#1273)

Thanks @jijinbei.

crates/doc/src/names.rs

@@ -0,0 +1,146 @@
+//! What a feature refers to: bodies and features by name, sketches by id. Each is saved as the
+//! plain name or id it wraps, but has its own type, so a body name can't be passed where a
+//! feature name or an expression is meant.
+
+use std::ops::Deref;
+
+use serde::{Deserialize, Serialize};
+
+macro_rules! name_type {
+    ($(#[$doc:meta])* $name:ident) => {
+        $(#[$doc])*
+        #[derive(Clone, Debug, Default, PartialEq, Eq, Hash, PartialOrd, Ord, Serialize, Deserialize)]
+        #[serde(transparent)]
+        pub struct $name(pub String);
+
+        impl Deref for $name {
+            type Target = str;
+            fn deref(&self) -> &str {
+                &self.0
+            }
+        }
+
+        impl AsRef<str> for $name {
+            fn as_ref(&self) -> &str {
+                &self.0
+            }
+        }
+
+        impl std::borrow::Borrow<str> for $name {
+            fn borrow(&self) -> &str {
+                &self.0
+            }
+        }
+
+        impl From<String> for $name {
+            fn from(s: String) -> Self {
+                $name(s)
+            }
+        }
+
+        impl From<&str> for $name {
+            fn from(s: &str) -> Self {
+                $name(s.to_string())
+            }
+        }
+
+        impl From<&String> for $name {
+            fn from(s: &String) -> Self {
+                $name(s.clone())
+            }
+        }
+
+        impl From<$name> for String {
+            fn from(n: $name) -> String {
+                n.0
+            }
+        }
+
+        impl std::fmt::Display for $name {
+            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+                f.write_str(&self.0)
+            }
+        }
+
+        impl PartialEq<str> for $name {
+            fn eq(&self, other: &str) -> bool {
+                self.0 == other
+            }
+        }
+
+        impl PartialEq<&str> for $name {
+            fn eq(&self, other: &&str) -> bool {
+                self.0 == *other
+            }
+        }
+
+        impl PartialEq<String> for $name {
+            fn eq(&self, other: &String) -> bool {
+                &self.0 == other
+            }
+        }
+
+        impl PartialEq<$name> for String {
+            fn eq(&self, other: &$name) -> bool {
+                *self == other.0
+            }
+        }
+
+        impl PartialEq<$name> for str {
+            fn eq(&self, other: &$name) -> bool {
+                self == other.0
+            }
+        }
+    };
+}
+
+name_type!(
+    /// A body, by name.
+    BodyName
+);
+name_type!(
+    /// A feature, by name.
+    FeatureName
+);
+
+/// A sketch, by its feature id.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash, PartialOrd, Ord, Serialize, Deserialize)]
+#[serde(transparent)]
+pub struct SketchId(pub u64);
+
+impl Deref for SketchId {
+    type Target = u64;
+    fn deref(&self) -> &u64 {
+        &self.0
+    }
+}
+
+impl From<u64> for SketchId {
+    fn from(id: u64) -> Self {
+        SketchId(id)
+    }
+}
+
+impl From<SketchId> for u64 {
+    fn from(id: SketchId) -> u64 {
+        id.0
+    }
+}
+
+impl PartialEq<u64> for SketchId {
+    fn eq(&self, other: &u64) -> bool {
+        self.0 == *other
+    }
+}
+
+impl PartialEq<SketchId> for u64 {
+    fn eq(&self, other: &SketchId) -> bool {
+        *self == other.0
+    }
+}
+
+impl std::fmt::Display for SketchId {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.0.fmt(f)
+    }
+}