Fix mesh member lookup

Author: nicklockwood

ShapeScript/Geometry.swift

@@ -614,8 +614,15 @@ private extension Collection where Element == Path {
 
 public extension Geometry {
     var hasMesh: Bool {
-        (path == nil && mesh?.polygons.isEmpty == false) ||
-            children.contains(where: { $0.hasMesh })
+        switch type {
+        case .camera, .light, .path:
+            return false
+        case .cone, .cylinder, .sphere, .cube,
+             .extrude, .lathe, .loft, .fill, .hull,
+             .union, .difference, .intersection, .xor, .stencil,
+             .group, .mesh:
+            return true
+        }
     }
 
     var objectCount: Int {

ShapeScript/Symbols.swift

@@ -316,12 +316,6 @@ extension Value {
                 members.append("last")
             }
             members += ["count", "allButFirst", "allButLast"]
-            if let string = self.as(.string) {
-                members += string.members
-            }
-            if !members.contains("alpha"), let color = self.as(.color) {
-                members += color.members
-            }
             if let vector = self.as(.vector) {
                 members += vector.members
             }
@@ -331,11 +325,24 @@ extension Value {
             if let rotation = self.as(.rotation) {
                 members += rotation.members
             }
+            if values.count == 1 {
+                return members + values[0].members
+            }
+            if let string = self.as(.string) {
+                members += string.members
+            }
+            if !members.contains("alpha"), let color = self.as(.color) {
+                members += color.members
+            }
             return members
         case .range:
             return ["start", "end", "step"]
-        case .mesh:
-            return ["name", "bounds", "polygons"]
+        case let .mesh(geometry):
+            var members = ["name", "bounds"]
+            if geometry.hasMesh {
+                members.append("polygons")
+            }
+            return members
         case .path, .polygon:
             return ["bounds", "points"]
         case let .point(point):
@@ -389,9 +396,6 @@ extension Value {
             default: return nil
             }
         case let .tuple(values):
-            if values.count == 1, case .tuple = values[0] {
-                return values[0][name]
-            }
             switch name {
             case "last":
                 return values.last
@@ -415,6 +419,9 @@ extension Value {
                 if let index = name.ordinalIndex {
                     return index < values.count ? values[index] : nil
                 }
+                if values.count == 1 {
+                    return values[0][name]
+                }
                 return nil
             }
         case let .range(range):
@@ -430,7 +437,7 @@ extension Value {
                 return .string(geometry.name ?? "")
             case "bounds":
                 return .bounds(geometry.bounds)
-            case "polygons":
+            case "polygons" where geometry.hasMesh:
                 _ = geometry.build { true }
                 let polygons = (geometry.mesh?.polygons ?? [])
                 return .tuple(polygons.map { .polygon($0) })

ShapeScriptTests/InterpreterTests.swift

@@ -3378,7 +3378,56 @@ class InterpreterTests: XCTestCase {
         XCTAssertEqual(delegate.log, [1])
     }
 
-    func testMeshComponentLookup() {
+    func testMeshBoundsLookup() {
+        let program = """
+        print (fill square).bounds
+        """
+        let delegate = TestDelegate()
+        XCTAssertNoThrow(try evaluate(parse(program), delegate: delegate))
+        XCTAssertEqual(delegate.log, [Bounds(
+            min: .init(-0.5, -0.5, 0),
+            max: .init(0.5, 0.5, 0)
+        )])
+    }
+
+    func testMeshPolygonsLookup() throws {
+        let program = """
+        print (fill square).polygons
+        """
+        let delegate = TestDelegate()
+        XCTAssertNoThrow(try evaluate(parse(program), delegate: delegate))
+        XCTAssertEqual(delegate.log, Mesh.fill(.square()).polygons)
+    }
+
+    func testPathPolygonsLookup() throws {
+        let program = """
+        print square.polygons
+        """
+        XCTAssertThrowsError(try evaluate(parse(program), delegate: nil)) { error in
+            let error = try? XCTUnwrap(error as? RuntimeError)
+            XCTAssertEqual(error?.message, "Unknown path member property 'polygons'")
+            guard case .unknownMember("polygons", of: "path", _)? = error?.type else {
+                XCTFail()
+                return
+            }
+        }
+    }
+
+    func testCameraPolygonsLookup() throws {
+        let program = """
+        print camera.polygons
+        """
+        XCTAssertThrowsError(try evaluate(parse(program), delegate: nil)) { error in
+            let error = try? XCTUnwrap(error as? RuntimeError)
+            XCTAssertEqual(error?.message, "Unknown mesh member property 'polygons'")
+            guard case .unknownMember("polygons", of: "mesh", _)? = error?.type else {
+                XCTFail()
+                return
+            }
+        }
+    }
+
+    func testInvalidMeshComponentLookup() {
         let program = """
         print (fill { circle }).x
         """