Implement DELOBJ source deletion policies

src/app/mod.rs

@@ -347,6 +347,52 @@ pub(crate) enum TextEntryMode {
     FreeText,
 }
 
+pub(crate) fn delobj_deletes_profiles(value: i16) -> bool {
+    value != 0
+}
+
+pub(crate) fn delobj_deletes_auxiliary(value: i16, creates_surface: bool) -> bool {
+    value == 2 || (value == 3 && !creates_surface)
+}
+
+pub(crate) fn delobj_deletes_conversion_source(value: i16) -> bool {
+    value >= 1
+}
+
+#[cfg(test)]
+mod delobj_policy_tests {
+    use super::{
+        delobj_deletes_auxiliary, delobj_deletes_conversion_source,
+        delobj_deletes_profiles,
+    };
+
+    #[test]
+    fn values_zero_through_three_select_the_expected_sources() {
+        assert_eq!(
+            (0..=3).map(delobj_deletes_profiles).collect::<Vec<_>>(),
+            [false, true, true, true]
+        );
+        assert_eq!(
+            (0..=3)
+                .map(|value| delobj_deletes_auxiliary(value, true))
+                .collect::<Vec<_>>(),
+            [false, false, true, false]
+        );
+        assert_eq!(
+            (0..=3)
+                .map(|value| delobj_deletes_auxiliary(value, false))
+                .collect::<Vec<_>>(),
+            [false, false, true, true]
+        );
+        assert_eq!(
+            (0..=3)
+                .map(delobj_deletes_conversion_source)
+                .collect::<Vec<_>>(),
+            [false, true, true, true]
+        );
+    }
+}
+
 pub(super) struct OpenCADStudio {
     start: Instant,
     control: control::State,
@@ -566,6 +612,8 @@ pub(super) struct OpenCADStudio {
     /// `MIRRTEXT`) — the next command-line entry is its new value, empty keeps
     /// the current one.
     pending_setvar: Option<String>,
+    /// DELOBJ system variable (0–3), shared by every open drawing.
+    delete_objects: i16,
     /// Cursor is hovering over the UCS icon body — drives the hover highlight.
     ucs_icon_hover: bool,
     /// UCS icon is selected (clicked): its grips are shown and draggable.
@@ -3424,6 +3472,7 @@ impl OpenCADStudio {
             block_usage_last_persist: None,
             awaiting_vports: false,
             pending_setvar: None,
+            delete_objects: 1,
             ucs_icon_hover: false,
             ucs_icon_selected: false,
             ucs_grip_drag: None,