feat(tui): render inline markdown formatting in the preview

DEMO.md

@@ -3,8 +3,8 @@
 This document is both a demo and an executable smoke test.
 
 Open it in the TUI with `upmd DEMO.md` and press Enter on any block to run it.
-Run with `upmd` (no args) to auto-open `up.md`, or use the file picker to
-select a different file. Headless execution: `upmd --all --yes DEMO.md`.
+Run one named block without the TUI with
+`upmd --cli --block stream --yes DEMO.md`.
 
 ## Getting started
 
@@ -14,23 +14,26 @@ A regular shell command. Select it and press Enter.
 ls
 ```
 
-An interactive prompt. Press `i` to focus the running block's inline terminal, type your name, then press Enter.
+## Markdown inline styles
 
-```sh
-read -p "Your name: " ME
-echo "Hi, $ME!"
-```
+Plain text, **bold**, *italic*, ~~strikethrough~~, `inline code`,
+[a link](https://github.com/rezigned/upmd "upmd repository"), and
+![the upmd logo](.github/pages/upmd-logo.png).
 
-Full terminal applications work inside the preview. Press `i` to interact, `o` for the full output view, `ctrl-o` to leave.
+Styles can be nested: ***bold italic***, **[a bold link](https://github.com/rezigned/upmd)**,
+and ~~*struck italic*~~.
 
-```sh
-nvim
-```
+### A heading with **bold**, *italic*, and `code`
+
+- A list item with **bold**, *italic*, ~~strikethrough~~, and `inline code`.
+- A linked image: [![upmd logo](.github/pages/upmd-square.svg)](https://upmd.rezigned.com/).
 
-> [!TIP]
-> Run `upmd` with no arguments to auto-open `up.md`, or browse the file picker.
+| Context | Styled example |
+|---|---|
+| Emphasis | **bold**, *italic*, and ***both*** |
+| Other | ~~strikethrough~~, `inline code`, and [link](https://upmd.rezigned.com/) |
 
-## 1. Streamed output
+## Streamed output
 
 Output appears inline while the block runs. The preview follows new rows only when they extend below the viewport.
 
@@ -43,7 +46,7 @@ done
 printf '\nReady.\n'
 ```
 
-## 2. ANSI colors and Unicode
+## ANSI colors and Unicode
 
 Every block runs in a real PTY, so ANSI escape codes and Unicode render correctly.
 
@@ -53,9 +56,9 @@ printf 'Unicode: café ภาษาไทย 🚀 ★\n'
 printf 'Bold: \033[1mimportant\033[0m  Dim: \033[2mquiet\033[0m  Underline: \033[4mlink\033[0m\n'
 ```
 
-## 3. Shell state persistence
+## Shell state persistence
 
-Shell runners automatically capture exported variables and the final working directory.
+Shell runners carry exported variables and the final working directory into later blocks.
 
 ```bash [name:set-state]
 export UPMD_DEMO_MESSAGE="state carried from the previous block"
@@ -65,7 +68,7 @@ cd "${TMPDIR:-/tmp}"
 printf 'Saved environment and cwd: %s\n' "$PWD"
 ```
 
-The next block reads the captured state. Notice that `$UPMD_DEMO_MESSAGE`, `$UPMD_DEMO_COLOR`, and `$PWD` are available despite being set in a separate process.
+The next block reads the state captured above.
 
 ```bash [name:read-state]
 printf 'Message: %s\n' "$UPMD_DEMO_MESSAGE"
@@ -74,9 +77,7 @@ printf 'Count: %s\n' "$UPMD_DEMO_COUNT"
 printf 'Working directory: %s\n' "$PWD"
 ```
 
-Press `e` in the TUI to inspect or edit the environment before running another block.
-
-## 4. Multiple language runners
+## Multiple language runners
 
 Python inherits state captured by the shell block.
 
@@ -99,7 +100,7 @@ console.log('Node version:', process.version);
 
 upmd also supports TypeScript, Ruby, PHP, C, Go, Rust, Zig, Fish, Zsh, Cmd, and PowerShell when their executables are installed.
 
-## 5. Named blocks and goto
+## Named blocks and goto
 
 Blocks with a `name` attribute are selectable by name or numeric ID.
 
@@ -109,9 +110,9 @@ printf 'Jump to it with: upmd DEMO.md --block named\n'
 printf 'Or press ctrl-g in the TUI and type "named".\n'
 ```
 
-## 6. Workflow dependencies
+## Workflow dependencies
 
-Blocks can declare dependencies on other blocks. Deps run first, and their captured environment (exported variables, working directory) is inherited by dependents.
+Dependencies run first and pass their captured environment and working directory to dependents.
 
 ```bash [name:build]
 sleep 1; export BIN_PATH="/tmp/demo"
@@ -130,42 +131,39 @@ printf 'test: %s\n' "$TEST_STATUS"
 
 ```bash [name:verify, deps:"lint | test"]
 read CONFIRM
-printf 'BIN_PATH=%s\n' "$BIN_PATH"
-printf 'LINT_REPORT=%s\n' "$LINT_REPORT"
-printf 'TEST_STATUS=%s\n' "$TEST_STATUS"
+printf "bin: $BIN_PATH, lint: $LINT_REPORT, test: $TEST_STATUS\n"
 printf 'verify: complete (%s).\n' "$CONFIRM"
 ```
 
-`lint` and `test` run in parallel after `build` finishes. Once both pass, `verify` runs and reads their captured state.
+`build` runs first. `lint` and `test` then run in parallel; `verify` waits for both.
+
+## TUI controls
 
-Press `'` while a workflow runs to toggle the inline dependency graph below the preview.
+Run an interactive prompt and press `i` to send it input:
 
-## 7. File picker and reload
+```sh
+read -p "Your name: " ME
+echo "Hi, $ME!"
+```
 
-- Press `f` to browse Markdown files relative to this document.
-- Type to filter matches while the selected file is previewed.
-- Press `ctrl-r` to reload the active file from disk and clear prior output.
-- Directory input works in both frontends: `upmd .` and `upmd --cli .`.
+Full-screen programs work inside the preview:
 
-## 8. Themes and help
+```sh
+nvim
+```
 
-- Press `t` to search and select a theme (tokyo-night, catppuccin-mocha, dracula, rose-pine, and more).
-- Press `ctrl-t` to toggle the terminal background.
-- Press `?` to open the searchable, sectioned keymap reference.
+- `i` focuses the selected process; `ctrl-o` leaves input mode.
+- `o` opens the full output view.
+- `f` browses Markdown files; typing filters the list.
+- `ctrl-r` reloads the active file and clears prior output.
+- `t` selects a theme; `ctrl-t` toggles the terminal background.
+- `e` inspects or edits captured environment state.
+- `'` toggles the dependency graph while a workflow runs.
+- `?` opens the searchable keymap reference.
+- Mouse input, wheel scrolling, drag selection, and `ctrl-v` paste work in PTY views.
 
 Print every configurable key and default binding:
 
 ```bash [name:dump-default-config]
 upmd --dump-default-config 2>/dev/null | head -20 || echo "dump-default-config unavailable"
 ```
-
-## 9. Interactive PTY and full output
-
-Every block runs in a pseudo-terminal. While a long-running or full-screen program is active:
-
-- Press `i` to focus its inline terminal and send keys directly.
-- Press `ctrl-o` to leave inline input mode.
-- Press `o` to open the full output view.
-- Mouse input is forwarded when the child enables SGR mouse reporting.
-- Otherwise wheel input scrolls local history and drag selection copies text.
-- Press `ctrl-v` to paste clipboard text into the process.

crates/upmd-parser/src/lib.rs

@@ -2,7 +2,7 @@ pub mod nodes;
 pub mod options;
 pub mod parser;
 
-pub use nodes::{Code, CodeId, Codes, Dependencies, Heading, Node};
+pub use nodes::{Code, CodeId, Codes, Dependencies, Heading, InlineSpan, InlineStyle, Node};
 
 /// Completeness of [`Document::nodes`].
 #[derive(Clone, Debug, Default, PartialEq, Eq)]

crates/upmd-parser/src/nodes.rs

@@ -3,16 +3,47 @@ use std::ops::Range;
 
 #[derive(Debug, Clone)]
 pub enum Node {
-    Heading { level: u8, text: String },
-    Paragraph(String),
+    Heading { level: u8, text: Vec<InlineSpan> },
+    Paragraph(Vec<InlineSpan>),
     BlockQuote(Vec<Node>),
     List(Vec<ListItem>),
     Code(CodeId),
     Table(Table),
-    Text(String),
+    Text(Vec<InlineSpan>),
     ThematicBreak,
 }
 
+/// A run of inline text with the formatting applied to it.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct InlineSpan {
+    pub text: String,
+    /// Active styles for this run. Empty means plain text; styles nest in
+    /// source order (e.g. bold inside italic becomes `[Italic, Bold]`).
+    pub style: Vec<InlineStyle>,
+}
+
+/// Inline markdown formatting applied to a [`InlineSpan`].
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum InlineStyle {
+    Bold,
+    Italic,
+    Strikethrough,
+    InlineCode,
+    Link {
+        destination: String,
+        title: Option<String>,
+    },
+    Image {
+        alt: String,
+        src: String,
+    },
+}
+
+/// Concatenates span text into a single plain string (for search, copy, menus).
+pub fn inline_text(spans: &[InlineSpan]) -> String {
+    spans.iter().map(|s| s.text.as_str()).collect()
+}
+
 /// Heading metadata collected during parsing.
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct Heading {
@@ -42,14 +73,32 @@ pub enum ListKind {
 pub struct ListItem {
     pub depth: usize,
     pub kind: ListKind,
-    pub text: String,
+    pub text: Vec<InlineSpan>,
     pub children: Vec<Node>,
 }
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct TableCell {
+    pub spans: Vec<InlineSpan>,
+}
+
+impl TableCell {
+    pub fn text(&self) -> String {
+        inline_text(&self.spans)
+    }
+
+    pub fn char_len(&self) -> usize {
+        self.spans
+            .iter()
+            .map(|span| span.text.chars().count())
+            .sum()
+    }
+}
+
 /// Markdown table with headers, rows, and column alignments.
 #[derive(Debug, Clone)]
 pub struct Table {
-    pub headers: Vec<String>,
-    pub rows: Vec<Vec<String>>,
+    pub headers: Vec<TableCell>,
+    pub rows: Vec<Vec<TableCell>>,
     pub alignments: Vec<Alignment>,
 }