Copy the 'content' from the Markdown or from it's focused child

[villekr]

(This question is a continuation topic for previous focus travelsal discussion #4227)

I'm looking for a recommended/preferred approach for copying content from a focused child of a Markdown widget.

In the following code I've added binding 'action_copy'.

• When parent Markdown widget is focused then I can get the content from protected '_markdown' attribute.
• When the focus is on Markdown child then it seems to get trickier. I tried to recurcively parse content out of child's 'renderable' attribute but that got messy.

Ideally the content would be the part of original markdown content that focused markdown child is rendering.

import pyperclip

# from rich.console import ConsoleRenderable, RichCast
from rich.syntax import Syntax
from textual.app import App, ComposeResult
from textual.binding import Binding
from textual.containers import Horizontal
from textual.widgets import Markdown, Static
from textual.widgets._markdown import (
    MarkdownBlock,
    MarkdownBullet,
    MarkdownFence,
)

EXAMPLE_MARKDOWN = """\
# Table of Contents
- [Section 1](#section-1)
  - [Subsection A](#subsection-a)
  - [Subsection B](#subsection-b)
- [Section 2](#section-2)
  - [Subsection C](#subsection-c)

This is an example of Textual's `Markdown` widget.

## Features

Markdown syntax and extensions are supported.

- Typography *emphasis*, **strong**, `inline code` etc.
- Headers
- Lists (bullet and ordered)
- Syntax highlighted code blocks

Nested lists:

- 1st level item
  - 2nd level item
    - 3rd level item

Some code:
~~~python
def do_something():
    pass
~~~
"""


class FocusableMarkdown(Markdown, can_focus=True, can_focus_children=False):
    BINDINGS = [
        Binding("enter", "enable_focus_children"),
        Binding("escape", "disable_focus_children"),
        Binding("tab,down,right", "focus_next", priority=True),
        Binding("shift+tab,up,left", "focus_previous", priority=True),
        Binding("c", "copy", "Copy", show=True, key_display="c", priority=True),
    ]

    DEFAULT_CSS = """
    FocusableMarkdown {
        border: tall transparent;
    }

    FocusableMarkdown:focus {
        border: tall $accent;
    }

    FocusableMarkdown > MarkdownBlock:focus {
        background: $accent;
    }
    """

    def action_enable_focus_children(self) -> None:
        self.can_focus_children = True
        for child in self.children:
            child.can_focus = True
        self.children[0].focus()

    def action_disable_focus_children(self) -> None:
        # If a MarkdownFence currently has focus, remove the highlighting
        if isinstance(self.screen.focused, MarkdownFence):
            self.update_fence_highlighting(
                fence=self.screen.focused,
                highlight=False,
            )

        self.can_focus_children = False
        for child in self.children:
            child.can_focus = False
        self.focus()

    def action_focus_next(self) -> None:
        if self.can_focus_children:
            # If a MarkdownFence currently has focus, remove the highlighting
            if isinstance(self.screen.focused, MarkdownFence):
                self.update_fence_highlighting(
                    fence=self.screen.focused,
                    highlight=False,
                )

            self.screen.focus_next("FocusableMarkdown *")
            # Now if the focused widget is a MarkdownFence, add the highlighting
            if isinstance(self.screen.focused, MarkdownFence):
                self.update_fence_highlighting(
                    fence=self.screen.focused, highlight=True
                )
        else:
            self.screen.focus_next()

    def action_focus_previous(self) -> None:
        if self.can_focus_children:
            # If a MarkdownFence currently has focus, remove the highlighting
            if isinstance(self.screen.focused, MarkdownFence):
                self.update_fence_highlighting(
                    fence=self.screen.focused,
                    highlight=False,
                )

            self.screen.focus_previous("FocusableMarkdown *")
            # Now if the focused widget is a MarkdownFence, add the highlighting
            if isinstance(self.screen.focused, MarkdownFence):
                self.update_fence_highlighting(
                    fence=self.screen.focused, highlight=True
                )
        else:
            self.screen.focus_previous()

    def update_fence_highlighting(
        self,
        fence: MarkdownFence,
        highlight: bool,
    ) -> None:
        if highlight:
            accent_color = "#0178D4"
            block = Syntax(
                fence.code,
                lexer=fence.lexer,
                word_wrap=False,
                indent_guides=True,
                padding=(1, 2),
                theme=fence.theme,
                background_color=accent_color,
            )
        else:
            block = Syntax(
                fence.code,
                lexer=fence.lexer,
                word_wrap=False,
                indent_guides=True,
                padding=(1, 2),
                theme=fence.theme,
            )

        fence.get_child_by_type(Static).update(block)

    def action_copy(self) -> None:
        if self.has_focus:
            content = self._markdown
        else:
            for child in self.children:
                if child.has_focus:
                    content = self.parse_from_children(child)

        print(f"{content=}")
        pyperclip.copy(content)

    def parse_from_children(self, block: MarkdownBlock, indent_depth: int = -2) -> str:
        children = block.children
        print(f"[{indent_depth}] {block=} {children=}")
        if len(children) > 0:
            text = ""
            for child in children:
                text += self.parse_from_children(child, indent_depth + 1)
            return text
        else:
            if isinstance(block, MarkdownBullet):
                return " " * indent_depth + "- "

            renderable_type = type(block.renderable)
            print(f"{renderable_type=}")
            return str(block.renderable) + "\n"


class FocusableMarkdownApp(App):
    CSS = """
    FocusableMarkdown {
        width: 50%;
        margin: 1 1 1 1;
    }
    """

    def compose(self) -> ComposeResult:
        with Horizontal():
            yield FocusableMarkdown(EXAMPLE_MARKDOWN)
            yield FocusableMarkdown(EXAMPLE_MARKDOWN)


if __name__ == "__main__":
    app = FocusableMarkdownApp()
    app.run()

[TomJGooding]

The Markdown widget is composed of various MarkdownBlock widgets. Have you looked at the source code to see if this might have any useful attributes?

[villekr]

I updated the code block in question with my initial attempt, which recursively collects content from markdown's child widgets. In order to handle indented lists some extra effort was needed.

For code block where renderable type rich.syntax.Syntax I haven't yet been able to figure out how to get it's content.

[TomJGooding]

For code block where renderable type rich.syntax.Syntax I haven't yet been able to figure out how to get it's content.

Your (well, my) update_fence_highlighting method creates a new Syntax object with the different backgrounds. Where does that get the content?

[villekr]

Thanks for pointing me to look for the solution from the correct place. Added one if-clause to parse_from_children and it works now.

    def parse_from_children(self, block: MarkdownBlock, indent_depth: int = -2) -> str:
        children = block.children
        print(f"[{indent_depth}] {block=} {children=}")

        if isinstance(block, MarkdownFence):
            return block.code

        if len(children) > 0:
            text = ""
            for child in children:
                text += self.parse_from_children(child, indent_depth + 1)
            return text
        else:
            if isinstance(block, MarkdownBullet):
                return " " * indent_depth + "- "
            renderable_type = type(block.renderable)
            print(f"{renderable_type=}")
            return str(block.renderable) + "\n"