Replace markdown editor with new 'EasyMark' markup language

egui_demo_lib/src/apps/demo/demo_windows.rs

@@ -16,7 +16,6 @@ impl Default for Demos {
             Box::new(super::dancing_strings::DancingStrings::default()),
             Box::new(super::drag_and_drop::DragAndDropDemo::default()),
             Box::new(super::font_book::FontBook::default()),
-            Box::new(super::markdown_editor::MarkdownEditor::default()),
             Box::new(super::painting::Painting::default()),
             Box::new(super::scrolling::Scrolling::default()),
             Box::new(super::sliders::Sliders::default()),

egui_demo_lib/src/apps/demo/markdown_editor.rs

@@ -1,66 +0,0 @@
-use egui::*;
-
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[derive(PartialEq)]
-pub struct MarkdownEditor {
-    markdown: String,
-}
-
-impl Default for MarkdownEditor {
-    fn default() -> Self {
-        Self {
-            markdown: r#"
-# Markdown editor
-Markdown support in egui is experimental, and *very* limited. There are:
-
-* bullet points
-  * with sub-points
-* `inline code`
-* *emphasis*
-* [hyperlinks](https://github.com/emilk/egui)
-
----
-
-Also the separator
-
-                "#
-            .trim_start()
-            .to_owned(),
-        }
-    }
-}
-
-impl super::Demo for MarkdownEditor {
-    fn name(&self) -> &str {
-        "🖹 Markdown Editor"
-    }
-
-    fn show(&mut self, ctx: &egui::CtxRef, open: &mut bool) {
-        egui::Window::new(self.name()).open(open).show(ctx, |ui| {
-            use super::View;
-            self.ui(ui);
-        });
-    }
-}
-
-impl super::View for MarkdownEditor {
-    fn ui(&mut self, ui: &mut egui::Ui) {
-        ui.vertical_centered(|ui| {
-            egui::reset_button(ui, self);
-            ui.add(crate::__egui_github_link_file!());
-        });
-        ui.separator();
-        ui.columns(2, |columns| {
-            ScrollArea::auto_sized()
-                .id_source("source")
-                .show(&mut columns[0], |ui| {
-                    ui.text_edit_multiline(&mut self.markdown);
-                });
-            ScrollArea::auto_sized()
-                .id_source("rendered")
-                .show(&mut columns[1], |ui| {
-                    egui::experimental::markdown(ui, &self.markdown);
-                });
-        });
-    }
-}

egui_demo_lib/src/apps/demo/mod.rs

@@ -14,7 +14,6 @@ pub mod font_contents_emoji;
 pub mod font_contents_ubuntu;
 pub mod input_test;
 pub mod layout_test;
-pub mod markdown_editor;
 pub mod painting;
 pub mod scrolling;
 pub mod sliders;

egui_demo_lib/src/apps/easy_mark_editor.rs

@@ -0,0 +1,117 @@
+use egui::*;
+
+#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[derive(PartialEq)]
+pub struct EasyMarkEditor {
+    code: String,
+}
+
+impl Default for EasyMarkEditor {
+    fn default() -> Self {
+        Self {
+            code: DEFAULT_CODE.trim().to_owned(),
+        }
+    }
+}
+
+impl epi::App for EasyMarkEditor {
+    fn name(&self) -> &str {
+        "🖹 EasyMark editor"
+    }
+
+    fn update(&mut self, ctx: &egui::CtxRef, _frame: &mut epi::Frame<'_>) {
+        egui::CentralPanel::default().show(ctx, |ui| {
+            self.ui(ui);
+        });
+    }
+}
+
+impl EasyMarkEditor {
+    fn ui(&mut self, ui: &mut egui::Ui) {
+        ui.vertical_centered(|ui| {
+            egui::reset_button(ui, self);
+            ui.add(crate::__egui_github_link_file!());
+        });
+        ui.separator();
+        ui.columns(2, |columns| {
+            ScrollArea::auto_sized()
+                .id_source("source")
+                .show(&mut columns[0], |ui| {
+                    // ui.text_edit_multiline(&mut self.code);
+                    ui.add(TextEdit::multiline(&mut self.code).text_style(TextStyle::Monospace));
+                });
+            ScrollArea::auto_sized()
+                .id_source("rendered")
+                .show(&mut columns[1], |ui| {
+                    egui::experimental::easy_mark(ui, &self.code);
+                });
+        });
+    }
+}
+
+const DEFAULT_CODE: &str = r#"
+# EasyMark
+EasyMark is a markup language, designed for extreme simplicity.
+
+```
+WARNING: EasyMark is still an evolving specification,
+and is also missing some features.
+```
+
+----------------
+
+# At a glance
+- inline text:
+  - normal, `code`, *strong*, ~strikethrough~, _underline_, /italics/
+  - `\` escapes the next character
+  - [hyperlink](https://github.com/emilk/egui)
+  - Embedded URL: <https://github.com/emilk/egui>
+- `# ` header
+- `---` separator (horizontal line)
+- `> ` quote
+- `- ` bullet list
+- `1. ` numbered list
+- \`\`\` code fence
+
+# Design
+> /"Why do what everyone else is doing, when everyone else is already doing it?"
+>   \- Emil
+
+Goals:
+1. easy to parse
+2. easy to learn
+3. similar to markdown
+
+[The reference parser](https://github.com/emilk/egui/blob/master/egui/src/experimental/easy_mark_parser.rs) is \~250 lines of code, using only the Rust standard library. The parser uses no look-ahead or recursion.
+
+There is never more than one way to accomplish the same thing, and each special character is only used for one thing. For instance `*` is used for *strong* and `-` is used for bullet lists. There is no alternative way to specify the *strong* style or getting a bullet list.
+
+Similarity to markdown is kept when possible, but with much less ambiguity and some improvements (like _underlining_).
+
+# Details
+All style changes are single characters, so it is `*strong*`, NOT `**strong**`. Style is reset by a matching character, or at the end of the line.
+
+Style change characters and escapes (`\`) work everywhere except for in inline code, code blocks and in URLs.
+
+You can mix styles. For instance: /italics _underline_/ and *strong `code`*.
+
+You can use styles on URLs: ~my webpage is at <http://www.example.com>~.
+
+Newlines are preserved. If you want to continue text on the same line, just do so. Alternatively, escape the newline by ending the line with a backslash (`\`). \
+Escaping the newline effectively ignores it.
+
+The style characters are chosen to be similar to what they are representing:
+  `_` = _underline_
+  `~` = ~strikethrough~ (`-` is too common in normal text)
+  `/` = /italics/
+  `*` = *strong*
+
+# TODO
+- Sub-headers (`## h2`, `### h3` etc)
+- Images
+  - we want to be able to optionally specify size (width and\/or height)
+  - centering of images is very desirable
+  - captioning (image with a text underneath it)
+  - `![caption=My image][width=200][center](url)` ?
+- Tables
+"#;

egui_demo_lib/src/apps/mod.rs

@@ -1,11 +1,13 @@
 mod color_test;
 mod demo;
+mod easy_mark_editor;
 mod fractal_clock;
 #[cfg(feature = "http")]
 mod http_app;
 
 pub use color_test::ColorTest;
 pub use demo::DemoApp;
+pub use easy_mark_editor::EasyMarkEditor;
 pub use fractal_clock::FractalClock;
 #[cfg(feature = "http")]
 pub use http_app::HttpApp;

egui_demo_lib/src/wrap_app.rs

@@ -4,6 +4,7 @@
 #[cfg_attr(feature = "persistence", serde(default))]
 pub struct Apps {
     demo: crate::apps::DemoApp,
+    easy_mark_editor: crate::apps::EasyMarkEditor,
     #[cfg(feature = "http")]
     http: crate::apps::HttpApp,
     clock: crate::apps::FractalClock,
@@ -14,6 +15,7 @@ impl Apps {
     fn iter_mut(&mut self) -> impl Iterator<Item = (&str, &mut dyn epi::App)> {
         vec![
             ("demo", &mut self.demo as &mut dyn epi::App),
+            ("easymark", &mut self.easy_mark_editor as &mut dyn epi::App),
             #[cfg(feature = "http")]
             ("http", &mut self.http as &mut dyn epi::App),
             ("clock", &mut self.clock as &mut dyn epi::App),