[tui] Clean up confusing caret types - raw and scroll adjusted

Caret position can be of two kinds:
- Raw
- Scroll adjusted

Make this explicity using the type system and provide
conversions between the two.

.vscode/settings.json

@@ -98,6 +98,7 @@
     "mworld",
     "nanos",
     "neovim",
+    "nextest",
     "Nodesource",
     "notcurses",
     "nushell",

core/src/tui_core/dimens/position.rs

@@ -14,9 +14,8 @@
  *   See the License for the specific language governing permissions and
  *   limitations under the License.
  */
-
 use std::{fmt::{self, Debug},
-          ops::{Add, AddAssign, Mul}};
+          ops::{Add, AddAssign, Mul, Sub}};
 
 use crate::{ChUnit, Size, ch};
 
@@ -144,8 +143,6 @@ impl Position {
 }
 
 pub mod position_math_ops {
-    use std::ops::Sub;
-
     use super::*;
 
     impl AddAssign<ChUnit> for Position {

core/src/tui_core/graphemes/access.rs

@@ -183,9 +183,10 @@ impl UnicodeString {
     /// Uses [SelectionRange] to calculate width and simply calls
     /// [clip_to_width](Self::clip_to_width).
     pub fn clip_to_range(&self, range: SelectionRange) -> &str {
+        // BUG: [ ] introduce scroll adjusted type
         let SelectionRange {
-            start_display_col_index,
-            end_display_col_index,
+            start_display_col_index_scroll_adjusted: start_display_col_index,
+            end_display_col_index_scroll_adjusted: end_display_col_index,
         } = range;
         let max_display_col_count = end_display_col_index - start_display_col_index;
         self.clip_to_width(start_display_col_index, max_display_col_count)

core/src/tui_core/graphemes/range.rs

@@ -38,9 +38,12 @@ use crate::{ChUnit, Position};
 /// - `▓▓` = `😃`
 /// - [clip_to_range](crate::UnicodeString::clip_to_range): "e😃"
 #[derive(Default, Clone, PartialEq, Copy, size_of::SizeOf)]
+// BUG: [ ] introduce scroll adjusted type
 pub struct SelectionRange {
-    pub start_display_col_index: ChUnit,
-    pub end_display_col_index: ChUnit,
+    /// This is not "raw", this is "scroll adjusted".
+    pub start_display_col_index_scroll_adjusted: ChUnit,
+    /// This is not "raw", this is "scroll adjusted".
+    pub end_display_col_index_scroll_adjusted: ChUnit,
 }
 
 #[derive(Clone, PartialEq, Copy, Debug)]
@@ -54,7 +57,7 @@ impl SelectionRange {
         &self,
         scroll_offset: Position,
     ) -> ScrollOffsetColLocationInRange {
-        if self.start_display_col_index >= scroll_offset.col_index {
+        if self.start_display_col_index_scroll_adjusted >= scroll_offset.col_index {
             ScrollOffsetColLocationInRange::Underflow
         } else {
             ScrollOffsetColLocationInRange::Overflow
@@ -163,9 +166,9 @@ impl SelectionRange {
     /// ```
     /// - [UnicodeString::clip_to_range](crate::UnicodeString::clip_to_range): "ell"
     pub fn locate_column(&self, caret_display_col_index: ChUnit) -> CaretLocationInRange {
-        if caret_display_col_index < self.start_display_col_index {
+        if caret_display_col_index < self.start_display_col_index_scroll_adjusted {
             CaretLocationInRange::Underflow
-        } else if caret_display_col_index >= self.end_display_col_index {
+        } else if caret_display_col_index >= self.end_display_col_index_scroll_adjusted {
             CaretLocationInRange::Overflow
         } else {
             CaretLocationInRange::Contained
@@ -174,8 +177,8 @@ impl SelectionRange {
 
     pub fn new(start_display_col_index: ChUnit, end_display_col_index: ChUnit) -> Self {
         Self {
-            start_display_col_index,
-            end_display_col_index,
+            start_display_col_index_scroll_adjusted: start_display_col_index,
+            end_display_col_index_scroll_adjusted: end_display_col_index,
         }
     }
 
@@ -189,7 +192,7 @@ impl SelectionRange {
     /// ```
     pub fn grow_end_by(&self, amount: ChUnit) -> Self {
         let mut copy = *self;
-        copy.end_display_col_index += amount;
+        copy.end_display_col_index_scroll_adjusted += amount;
         copy
     }
 
@@ -203,7 +206,7 @@ impl SelectionRange {
     /// ```
     pub fn shrink_end_by(&self, amount: ChUnit) -> Self {
         let mut copy = *self;
-        copy.end_display_col_index -= amount;
+        copy.end_display_col_index_scroll_adjusted -= amount;
         copy
     }
 
@@ -217,7 +220,7 @@ impl SelectionRange {
     /// ```
     pub fn grow_start_by(&self, amount: ChUnit) -> Self {
         let mut copy = *self;
-        copy.start_display_col_index -= amount;
+        copy.start_display_col_index_scroll_adjusted -= amount;
         copy
     }
 
@@ -231,7 +234,7 @@ impl SelectionRange {
     /// ```
     pub fn shrink_start_by(&self, amount: ChUnit) -> Self {
         let mut copy = *self;
-        copy.start_display_col_index += amount;
+        copy.start_display_col_index_scroll_adjusted += amount;
         copy
     }
 }
@@ -244,8 +247,8 @@ mod range_impl_debug_format {
             write!(
                 f,
                 "[start_display_col_index: {start:?}, end_display_col_index: {end:?}]",
-                start = self.start_display_col_index,
-                end = self.end_display_col_index
+                start = self.start_display_col_index_scroll_adjusted,
+                end = self.end_display_col_index_scroll_adjusted
             )
         }
     }

run

@@ -148,6 +148,7 @@ def install-cargo-tools [] {
     cargo install cargo-unmaintained
     cargo install cargo-expand
     cargo install cargo-readme
+    cargo install cargo-nextest
 }
 
 def all [] {