Adding endif row, optional draggable rows (#6)

* Added endif row

* Optional draggable rows

Author: adborbas

Source/Yasba/Views/Sieve Script/Row Token/RowToken.swift

@@ -25,4 +25,11 @@ enum RowToken: Identifiable, Equatable {
         default: return true
         }
     }
+    
+    var canDrag: Bool {
+        switch self {
+        case .elseMarker, .endIf: return false
+        default: return true
+        }
+    }
 }

Source/Yasba/Views/Sieve Script/Row Token/RowTokenToViewMapper.swift

@@ -11,7 +11,7 @@ enum RowTokenToViewMapper {
         case .elseMarker:
             TextRowView(icon: "arrow.triangle.branch", title: "Else")
         case .endIf:
-            EmptyView()
+            TextRowView(icon: "arrow.triangle.branch", title: "Endif")
         case .leaf(let command):
             registry.makeView(for: command)
         }

Source/Yasba/Views/Sieve Script/SieveScriptView.swift

@@ -112,8 +112,6 @@ struct SieveScriptView: View {
         }
         if let range = draggedRange, range.contains(index) {
             EmptyView()
-        } else if case .endIf = token {
-            EmptyView()
         } else {
             tokenRow(index: index, token: token)
         }
@@ -158,11 +156,13 @@ struct SieveScriptView: View {
         .padding(.leading, CGFloat(indents[index]) * 24)
         .contentShape(Rectangle())
         .onHover { hovering in hoveredRow = hovering ? index : nil }
-        .onDrag {
-            let span = viewModel.dragSpan(at: index, in: tokens)
-            draggedRange = span
-            dropGapIndex = span.lowerBound
-            return NSItemProvider(object: token.id.uuidString as NSString)
+        .applyIf(token.canDrag) { view in
+            view.onDrag {
+                let span = viewModel.dragSpan(at: index, in: tokens)
+                draggedRange = span
+                dropGapIndex = span.lowerBound
+                return NSItemProvider(object: token.id.uuidString as NSString)
+            }
         }
         .onDrop(of: [UTType.utf8PlainText],
                 delegate: UnifiedDropDelegate(target: .row(index),

Source/Yasba/Views/View+applyIf.swift

@@ -0,0 +1,8 @@
+import SwiftUI
+
+extension View {
+    @ViewBuilder
+    func applyIf<T: View>(_ condition: Bool, transform: (Self) -> T) -> some View {
+        if condition { transform(self) } else { self }
+    }
+}