solid.cylinder, box, sphere, torus and coil place by expressions: base, corner and center take numbers or length expressions per coordinate ("basin_width/2", "10 mm") and follow parameter changes, renames and component frames; before, a point that was not three plain numbers (or an unreadable axis) was silently replaced by the origin (or Z). The features now store the point as expressions (plain numbers still saved as numbers, so existing designs read and write the same) and evaluate it on every recompute; an unreadable or out-of-range point or axis is refused with an error. Tests: primitive points take expressions, follow parameters, renames and a moved component, and bad points are refused

crates/doc/src/document.rs

@@ -226,7 +226,8 @@ pub enum FeatureKind {
         body: Option<String>,
     },
     Box {
-        corner: Vec3,
+        #[serde(with = "point_expr")]
+        corner: PointExpr,
         length: String,
         width: String,
         height: String,
@@ -234,7 +235,8 @@ pub enum FeatureKind {
         operation: Operation,
     },
     Cylinder {
-        base: Vec3,
+        #[serde(with = "point_expr")]
+        base: PointExpr,
         #[serde(default = "z_axis")]
         axis: Vec3,
         radius: String,
@@ -243,13 +245,15 @@ pub enum FeatureKind {
         operation: Operation,
     },
     Sphere {
-        center: Vec3,
+        #[serde(with = "point_expr")]
+        center: PointExpr,
         radius: String,
         #[serde(default)]
         operation: Operation,
     },
     Torus {
-        center: Vec3,
+        #[serde(with = "point_expr")]
+        center: PointExpr,
         major: String,
         minor: String,
         #[serde(default)]
@@ -482,7 +486,8 @@ pub enum FeatureKind {
     /// A helical coil: a circular or square section swept `turns` times about `axis`, rising
     /// `pitch` per turn, on a helix of `diameter` (the section's centre, or its inside or outside).
     Coil {
-        base: Vec3,
+        #[serde(with = "point_expr")]
+        base: PointExpr,
         #[serde(default = "z_axis")]
         axis: Vec3,
         diameter: String,
@@ -939,6 +944,45 @@ fn z_axis() -> Vec3 {
     Vec3::Z
 }
 
+/// A point whose coordinates are length expressions (`["basin_width / 2", "10 mm", "0"]`), so
+/// it follows parameter changes. Primitives are placed by one.
+pub type PointExpr = [String; 3];
+
+/// A point as expressions (plain numbers, mm).
+pub fn point_expr(p: Vec3) -> PointExpr {
+    [format!("{}", p.x), format!("{}", p.y), format!("{}", p.z)]
+}
+
+/// Stored as `[x, y, z]`: plain numbers as numbers (as points were before they took
+/// expressions, so such designs read and write the same), anything else as a string.
+mod point_expr {
+    use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(untagged)]
+    enum Coord {
+        Num(f64),
+        Expr(String),
+    }
+
+    pub fn serialize<S: Serializer>(p: &super::PointExpr, s: S) -> Result<S::Ok, S::Error> {
+        let c = |e: &String| match e.parse::<f64>() {
+            Ok(v) if v.is_finite() && format!("{v}") == *e => Coord::Num(v),
+            _ => Coord::Expr(e.clone()),
+        };
+        [c(&p[0]), c(&p[1]), c(&p[2])].serialize(s)
+    }
+
+    pub fn deserialize<'de, D: Deserializer<'de>>(d: D) -> Result<super::PointExpr, D::Error> {
+        let c = |x: Coord| match x {
+            Coord::Num(v) => format!("{v}"),
+            Coord::Expr(e) => e,
+        };
+        let [x, y, z] = <[Coord; 3]>::deserialize(d)?;
+        Ok([c(x), c(y), c(z)])
+    }
+}
+
 impl FeatureKind {
     /// Sketches the feature is built from (profiles, paths, points): deleting one of them
     /// deletes the feature. Every kind is listed, so a new one has to say what it uses.
@@ -1228,10 +1272,22 @@ impl FeatureKind {
                 v.extend(distance2.iter().map(String::as_str));
                 v.extend(angle.iter().map(String::as_str));
             }
-            FeatureKind::Box { length, width, height, .. } => v.extend([length.as_str(), width, height]),
-            FeatureKind::Cylinder { radius, height, .. } => v.extend([radius.as_str(), height]),
-            FeatureKind::Sphere { radius, .. } => v.push(radius),
-            FeatureKind::Torus { major, minor, .. } => v.extend([major.as_str(), minor]),
+            FeatureKind::Box { length, width, height, corner, .. } => {
+                v.extend([length.as_str(), width, height]);
+                v.extend(corner.iter().map(String::as_str));
+            }
+            FeatureKind::Cylinder { radius, height, base, .. } => {
+                v.extend([radius.as_str(), height]);
+                v.extend(base.iter().map(String::as_str));
+            }
+            FeatureKind::Sphere { radius, center, .. } => {
+                v.push(radius);
+                v.extend(center.iter().map(String::as_str));
+            }
+            FeatureKind::Torus { major, minor, center, .. } => {
+                v.extend([major.as_str(), minor]);
+                v.extend(center.iter().map(String::as_str));
+            }
             FeatureKind::Combine { .. } => {}
             FeatureKind::Pattern { pattern, .. } => match pattern {
                 PatternKind::Rectangular { count1, spacing1, count2, spacing2, .. } => {
@@ -1308,9 +1364,10 @@ impl FeatureKind {
                 v.extend(gap.iter().map(String::as_str));
             }
             FeatureKind::SheetBase { .. } | FeatureKind::SheetUnfold { .. } | FeatureKind::SheetConvert { .. } => {}
-            FeatureKind::Coil { diameter, pitch, turns, section_size, start_angle, .. } => {
+            FeatureKind::Coil { diameter, pitch, turns, section_size, start_angle, base, .. } => {
                 v.extend([diameter.as_str(), pitch, turns, section_size]);
                 v.extend(start_angle.iter().map(String::as_str));
+                v.extend(base.iter().map(String::as_str));
             }
             FeatureKind::Rib { thickness, depth, .. } => {
                 v.push(thickness);