Allow TextEdit to represent and validate generic types

Cargo.lock

@@ -4107,6 +4107,14 @@ dependencies = [
  "env_logger",
 ]
 
+[[package]]
+name = "text_validation"
+version = "0.1.0"
+dependencies = [
+ "eframe",
+ "env_logger",
+]
+
 [[package]]
 name = "thiserror"
 version = "1.0.66"

crates/egui/src/ui.rs

@@ -2038,7 +2038,7 @@ impl Ui {
     /// No newlines (`\n`) allowed. Pressing enter key will result in the [`TextEdit`] losing focus (`response.lost_focus`).
     ///
     /// See also [`TextEdit`].
-    pub fn text_edit_singleline<S: widgets::text_edit::TextBuffer>(
+    pub fn text_edit_singleline<S: widgets::text_edit::TextType>(
         &mut self,
         text: &mut S,
     ) -> Response {
@@ -2048,7 +2048,7 @@ impl Ui {
     /// A [`TextEdit`] for multiple lines. Pressing enter key will create a new line.
     ///
     /// See also [`TextEdit`].
-    pub fn text_edit_multiline<S: widgets::text_edit::TextBuffer>(
+    pub fn text_edit_multiline<S: widgets::text_edit::TextType>(
         &mut self,
         text: &mut S,
     ) -> Response {
@@ -2060,7 +2060,7 @@ impl Ui {
     /// This will be multiline, monospace, and will insert tabs instead of moving focus.
     ///
     /// See also [`TextEdit::code_editor`].
-    pub fn code_editor<S: widgets::text_edit::TextBuffer>(&mut self, text: &mut S) -> Response {
+    pub fn code_editor<S: widgets::text_edit::TextType>(&mut self, text: &mut S) -> Response {
         self.add(TextEdit::multiline(text).code_editor())
     }
 

crates/egui/src/widgets/mod.rs

@@ -41,7 +41,7 @@ pub use self::{
     separator::Separator,
     slider::{Slider, SliderClamping, SliderOrientation},
     spinner::Spinner,
-    text_edit::{TextBuffer, TextEdit},
+    text_edit::{TextBuffer, TextEdit, TextType},
 };
 
 // ----------------------------------------------------------------------------

crates/egui/src/widgets/text_edit/builder.rs

@@ -17,7 +17,7 @@ use crate::{
     vec2,
 };
 
-use super::{TextEditOutput, TextEditState};
+use super::{TextEditOutput, TextEditState, text_type::TextType};
 
 type LayouterFn<'t> = &'t mut dyn FnMut(&Ui, &dyn TextBuffer, f32) -> Arc<Galley>;
 
@@ -65,8 +65,8 @@ type LayouterFn<'t> = &'t mut dyn FnMut(&Ui, &dyn TextBuffer, f32) -> Arc<Galley
 /// ## Other
 /// The background color of a [`crate::TextEdit`] is [`crate::Visuals::text_edit_bg_color`] or can be set with [`crate::TextEdit::background_color`].
 #[must_use = "You should put this widget in a ui with `ui.add(widget);`"]
-pub struct TextEdit<'t> {
-    text: &'t mut dyn TextBuffer,
+pub struct TextEdit<'t, Value: TextType = String> {
+    represents: &'t mut Value,
     hint_text: WidgetText,
     hint_text_font: Option<FontSelection>,
     id: Option<Id>,
@@ -91,11 +91,13 @@ pub struct TextEdit<'t> {
     background_color: Option<Color32>,
 }
 
-impl WidgetWithState for TextEdit<'_> {
+impl<Value: TextType> WidgetWithState for TextEdit<'_, Value> {
     type State = TextEditState;
 }
 
-impl TextEdit<'_> {
+// This doesn't have to be a string.
+// It's just to prevent having specify the generic type, as it's not used by these functions
+impl TextEdit<'_, String> {
     pub fn load_state(ctx: &Context, id: Id) -> Option<TextEditState> {
         TextEditState::load(ctx, id)
     }
@@ -105,21 +107,21 @@ impl TextEdit<'_> {
     }
 }
 
-impl<'t> TextEdit<'t> {
+impl<'t, Value: TextType> TextEdit<'t, Value> {
     /// No newlines (`\n`) allowed. Pressing enter key will result in the [`TextEdit`] losing focus (`response.lost_focus`).
-    pub fn singleline(text: &'t mut dyn TextBuffer) -> Self {
+    pub fn singleline(value: &'t mut Value) -> Self {
         Self {
             desired_height_rows: 1,
             multiline: false,
             clip_text: true,
-            ..Self::multiline(text)
+            ..Self::multiline(value)
         }
     }
 
     /// A [`TextEdit`] for multiple lines. Pressing enter key will create a new line by default (can be changed with [`return_key`](TextEdit::return_key)).
-    pub fn multiline(text: &'t mut dyn TextBuffer) -> Self {
+    pub fn multiline(value: &'t mut Value) -> Self {
         Self {
-            text,
+            represents: value,
             hint_text: Default::default(),
             hint_text_font: None,
             id: None,
@@ -277,7 +279,6 @@ impl<'t> TextEdit<'t> {
         layouter: &'t mut dyn FnMut(&Ui, &dyn TextBuffer, f32) -> Arc<Galley>,
     ) -> Self {
         self.layouter = Some(layouter);
-
         self
     }
 
@@ -400,13 +401,13 @@ impl<'t> TextEdit<'t> {
 
 // ----------------------------------------------------------------------------
 
-impl Widget for TextEdit<'_> {
+impl<Value: TextType> Widget for TextEdit<'_, Value> {
     fn ui(self, ui: &mut Ui) -> Response {
         self.show(ui).response
     }
 }
 
-impl TextEdit<'_> {
+impl<Value: TextType> TextEdit<'_, Value> {
     /// Show the [`TextEdit`], returning a rich [`TextEditOutput`].
     ///
     /// ```
@@ -423,7 +424,7 @@ impl TextEdit<'_> {
     /// # });
     /// ```
     pub fn show(self, ui: &mut Ui) -> TextEditOutput {
-        let is_mutable = self.text.is_mutable();
+        let is_mutable = Value::is_mutable();
         let frame = self.frame;
         let where_to_put_background = ui.painter().add(Shape::Noop);
         let background_color = self
@@ -470,7 +471,7 @@ impl TextEdit<'_> {
 
     fn show_content(self, ui: &mut Ui) -> TextEditOutput {
         let TextEdit {
-            text,
+            represents,
             hint_text,
             hint_text_font,
             id,
@@ -495,6 +496,21 @@ impl TextEdit<'_> {
             background_color: _,
         } = self;
 
+        // An Id is required, as the displayed string is owned by the state.
+        let id = id.unwrap_or_else(|| {
+            if let Some(id_salt) = id_salt {
+                ui.make_persistent_id(id_salt)
+            } else {
+                ui.next_auto_id()
+            }
+        });
+
+        let mut state = TextEditState::load(ui.ctx(), id).unwrap_or_default();
+        let mut text = state
+            .text
+            .clone()
+            .unwrap_or_else(|| represents.string_representation());
+
         let text_color = text_color
             .or(ui.visuals().override_text_color)
             // .unwrap_or_else(|| ui.style().interact(&response).text_color()); // too bright
@@ -527,7 +543,7 @@ impl TextEdit<'_> {
 
         let layouter = layouter.unwrap_or(&mut default_layouter);
 
-        let mut galley = layouter(ui, text, wrap_width);
+        let mut galley = layouter(ui, &text, wrap_width);
 
         let desired_inner_width = if clip_text {
             wrap_width // visual clipping with scroll in singleline input.
@@ -537,18 +553,9 @@ impl TextEdit<'_> {
         let desired_height = (desired_height_rows.at_least(1) as f32) * row_height;
         let desired_inner_size = vec2(desired_inner_width, galley.size().y.max(desired_height));
         let desired_outer_size = (desired_inner_size + margin.sum()).at_least(min_size);
-        let (auto_id, outer_rect) = ui.allocate_space(desired_outer_size);
+        let outer_rect = ui.allocate_space(desired_outer_size).1;
         let rect = outer_rect - margin; // inner rect (excluding frame/margin).
 
-        let id = id.unwrap_or_else(|| {
-            if let Some(id_salt) = id_salt {
-                ui.make_persistent_id(id_salt)
-            } else {
-                auto_id // Since we are only storing the cursor a persistent Id is not super important
-            }
-        });
-        let mut state = TextEditState::load(ui.ctx(), id).unwrap_or_default();
-
         // On touch screens (e.g. mobile in `eframe` web), should
         // dragging select text, or scroll the enclosing [`ScrollArea`] (if any)?
         // Since currently copying selected text in not supported on `eframe` web,
@@ -575,7 +582,7 @@ impl TextEdit<'_> {
 
         if interactive {
             if let Some(pointer_pos) = response.interact_pointer_pos() {
-                if response.hovered() && text.is_mutable() {
+                if response.hovered() && Value::is_mutable() {
                     ui.output_mut(|o| o.mutable_text_under_cursor = true);
                 }
 
@@ -629,7 +636,7 @@ impl TextEdit<'_> {
             let (changed, new_cursor_range) = events(
                 ui,
                 &mut state,
-                text,
+                &mut text,
                 &mut galley,
                 layouter,
                 id,
@@ -773,7 +780,7 @@ impl TextEdit<'_> {
                         ui.scroll_to_rect(primary_cursor_rect + margin, None);
                     }
 
-                    if text.is_mutable() && interactive {
+                    if Value::is_mutable() && interactive {
                         let now = ui.ctx().input(|i| i.time);
                         if response.changed() || selection_changed {
                             state.last_interaction_time = now;
@@ -820,9 +827,36 @@ impl TextEdit<'_> {
             ui.input_mut(|i| i.events.retain(|e| !matches!(e, Event::Ime(_))));
         }
 
-        state.clone().store(ui.ctx(), id);
+        // TODO(tye-exe): Simplify once https://github.com/emilk/egui/issues/2142 is fixed
+        if response.lost_focus() || response.clicked_elsewhere() {
+            // TODO(tye-exe): Parsing can be skipped if the text has not changed
+            // since the value is updated in real time.
+            // However, the reason for parsing failure would not get logged.
+            match Value::read_from_string(&represents, &text) {
+                Some(Ok(var)) => *represents = var,
+                Some(Err(err)) => {
+                    #[cfg(feature = "log")]
+                    log::info!("Failed to parse value for text edit: {err}");
+                }
+                None =>
+                {
+                    #[cfg(feature = "log")]
+                    if Value::is_mutable() {
+                        log::warn!("Incorrectly marked unparsable TextType as mutable.",)
+                    }
+                }
+            }
+
+            // The user might have changed the text
+            text = represents.string_representation()
+        }
 
         if response.changed() {
+            // Update represented value if the current state is valid
+            if let Some(Ok(var)) = Value::read_from_string(&represents, &text) {
+                *represents = var
+            };
+
             response.widget_info(|| {
                 WidgetInfo::text_edit(
                     ui.is_enabled(),
@@ -871,6 +905,9 @@ impl TextEdit<'_> {
             );
         }
 
+        state.text = Some(text);
+        state.clone().store(ui.ctx(), id);
+
         TextEditOutput {
             response,
             galley,
@@ -905,7 +942,7 @@ fn mask_if_password(is_password: bool, text: &str) -> String {
 fn events(
     ui: &crate::Ui,
     state: &mut TextEditState,
-    text: &mut dyn TextBuffer,
+    text: &mut String,
     galley: &mut Arc<Galley>,
     layouter: &mut dyn FnMut(&Ui, &dyn TextBuffer, f32) -> Arc<Galley>,
     id: Id,

crates/egui/src/widgets/text_edit/mod.rs

@@ -2,8 +2,9 @@ mod builder;
 mod output;
 mod state;
 mod text_buffer;
+mod text_type;
 
 pub use {
     crate::text_selection::TextCursorState, builder::TextEdit, output::TextEditOutput,
-    state::TextEditState, text_buffer::TextBuffer,
+    state::TextEditState, text_buffer::TextBuffer, text_type::TextType,
 };

crates/egui/src/widgets/text_edit/state.rs

@@ -37,6 +37,11 @@ pub struct TextEditState {
     /// Controls the text selection.
     pub cursor: TextCursorState,
 
+    // TODO(tye-exe): Should this be public?
+    /// Displayed string.
+    /// This may differ from the value represented if the user is actively editing the string.
+    pub text: Option<String>,
+
     /// Wrapped in Arc for cheaper clones.
     #[cfg_attr(feature = "serde", serde(skip))]
     pub(crate) undoer: Arc<Mutex<TextEditUndoer>>,

crates/egui/src/widgets/text_edit/text_buffer.rs

@@ -18,9 +18,6 @@ use crate::{
 ///
 /// Most likely you will use a [`String`] which implements [`TextBuffer`].
 pub trait TextBuffer {
-    /// Can this text be edited?
-    fn is_mutable(&self) -> bool;
-
     /// Returns this buffer as a `str`.
     fn as_str(&self) -> &str;
 
@@ -212,10 +209,6 @@ pub trait TextBuffer {
 }
 
 impl TextBuffer for String {
-    fn is_mutable(&self) -> bool {
-        true
-    }
-
     fn as_str(&self) -> &str {
         self.as_ref()
     }
@@ -260,58 +253,3 @@ impl TextBuffer for String {
         std::any::TypeId::of::<Self>()
     }
 }
-
-impl TextBuffer for Cow<'_, str> {
-    fn is_mutable(&self) -> bool {
-        true
-    }
-
-    fn as_str(&self) -> &str {
-        self.as_ref()
-    }
-
-    fn insert_text(&mut self, text: &str, char_index: usize) -> usize {
-        <String as TextBuffer>::insert_text(self.to_mut(), text, char_index)
-    }
-
-    fn delete_char_range(&mut self, char_range: Range<usize>) {
-        <String as TextBuffer>::delete_char_range(self.to_mut(), char_range);
-    }
-
-    fn clear(&mut self) {
-        <String as TextBuffer>::clear(self.to_mut());
-    }
-
-    fn replace_with(&mut self, text: &str) {
-        *self = Cow::Owned(text.to_owned());
-    }
-
-    fn take(&mut self) -> String {
-        std::mem::take(self).into_owned()
-    }
-
-    fn type_id(&self) -> std::any::TypeId {
-        std::any::TypeId::of::<Cow<'_, str>>()
-    }
-}
-
-/// Immutable view of a `&str`!
-impl TextBuffer for &str {
-    fn is_mutable(&self) -> bool {
-        false
-    }
-
-    fn as_str(&self) -> &str {
-        self
-    }
-
-    fn insert_text(&mut self, _text: &str, _ch_idx: usize) -> usize {
-        0
-    }
-
-    fn delete_char_range(&mut self, _ch_range: Range<usize>) {}
-
-    fn type_id(&self) -> std::any::TypeId {
-        std::any::TypeId::of::<&str>()
-    }
-}