Source code for rich.markdown

from typing import Any, ClassVar, Dict, List, Optional, Type, Union

from commonmark.blocks import Parser

from . import box
from ._loop import loop_first
from ._stack import Stack
from .console import Console, ConsoleOptions, JustifyMethod, RenderResult
from .containers import Renderables
from .jupyter import JupyterMixin
from .panel import Panel
from .rule import Rule
from .segment import Segment
from .style import Style, StyleStack
from .syntax import Syntax
from .text import Text, TextType


class MarkdownElement:

    new_line: ClassVar[bool] = True

    @classmethod
    def create(cls, markdown: "Markdown", node: Any) -> "MarkdownElement":
        """Factory to create markdown element,

        Args:
            markdown (Markdown): THe parent Markdown object.
            node (Any): A node from Pygments.

        Returns:
            MarkdownElement: A new markdown element
        """
        return cls()

    def on_enter(self, context: "MarkdownContext") -> None:
        """Called when the node is entered.

        Args:
            context (MarkdownContext): The markdown context.
        """

    def on_text(self, context: "MarkdownContext", text: TextType) -> None:
        """Called when text is parsed.

        Args:
            context (MarkdownContext): The markdown context.
        """

    def on_leave(self, context: "MarkdownContext") -> None:
        """Called when the parser leaves the element.

        Args:
            context (MarkdownContext): [description]
        """

    def on_child_close(
        self, context: "MarkdownContext", child: "MarkdownElement"
    ) -> bool:
        """Called when a child element is closed.

        This method allows a parent element to take over rendering of its children.

        Args:
            context (MarkdownContext): The markdown context.
            child (MarkdownElement): The child markdown element.

        Returns:
            bool: Return True to render the element, or False to not render the element.
        """
        return True

    def __rich_console__(
        self, console: "Console", options: "ConsoleOptions"
    ) -> "RenderResult":
        return ()


[docs]class UnknownElement(MarkdownElement): """An unknown element. Hopefully there will be no unknown elements, and we will have a MarkdownElement for everything in the document. """
[docs]class TextElement(MarkdownElement): """Base class for elements that render text.""" style_name = "none"
[docs] def on_enter(self, context: "MarkdownContext") -> None: self.style = context.enter_style(self.style_name) self.text = Text(justify="left")
[docs] def on_text(self, context: "MarkdownContext", text: TextType) -> None: self.text.append(text, context.current_style if isinstance(text, str) else None)
[docs] def on_leave(self, context: "MarkdownContext") -> None: context.leave_style()
[docs]class Paragraph(TextElement): """A Paragraph.""" style_name = "markdown.paragraph" justify: JustifyMethod @classmethod def create(cls, markdown: "Markdown", node: MarkdownElement) -> "Paragraph": return cls(justify=markdown.justify or "left") def __init__(self, justify: JustifyMethod) -> None: self.justify = justify def __rich_console__( self, console: Console, options: ConsoleOptions ) -> RenderResult: self.text.justify = self.justify yield self.text
[docs]class Heading(TextElement): """A heading.""" @classmethod def create(cls, markdown: "Markdown", node: Any) -> "Heading": heading = cls(node.level) return heading
[docs] def on_enter(self, context: "MarkdownContext") -> None: self.text = Text() context.enter_style(self.style_name)
def __init__(self, level: int) -> None: self.level = level self.style_name = f"markdown.h{level}" super().__init__() def __rich_console__( self, console: Console, options: ConsoleOptions ) -> RenderResult: text = self.text text.justify = "center" if self.level == 1: # Draw a border around h1s yield Panel( text, box=box.DOUBLE, style="markdown.h1.border", ) else: # Styled text for h2 and beyond if self.level == 2: yield Text("") yield text
[docs]class CodeBlock(TextElement): """A code block with syntax highlighting.""" style_name = "markdown.code_block" @classmethod def create(cls, markdown: "Markdown", node: Any) -> "CodeBlock": node_info = node.info or "" lexer_name = node_info.partition(" ")[0] return cls(lexer_name or "default", markdown.code_theme) def __init__(self, lexer_name: str, theme: str) -> None: self.lexer_name = lexer_name self.theme = theme def __rich_console__( self, console: Console, options: ConsoleOptions ) -> RenderResult: code = str(self.text).rstrip() syntax = Panel( Syntax(code, self.lexer_name, theme=self.theme), border_style="dim", box=box.SQUARE, ) yield syntax
[docs]class BlockQuote(TextElement): """A block quote.""" style_name = "markdown.block_quote" def __init__(self) -> None: self.elements: Renderables = Renderables()
[docs] def on_child_close( self, context: "MarkdownContext", child: "MarkdownElement" ) -> bool: self.elements.append(child) return False
def __rich_console__( self, console: Console, options: ConsoleOptions ) -> RenderResult: render_options = options.update(width=options.max_width - 4) lines = console.render_lines(self.elements, render_options, style=self.style) style = self.style new_line = Segment("\n") padding = Segment("▌ ", style) for line in lines: yield padding yield from line yield new_line
[docs]class HorizontalRule(MarkdownElement): """A horizontal rule to divide sections.""" new_line = False def __rich_console__( self, console: Console, options: ConsoleOptions ) -> RenderResult: style = console.get_style("markdown.hr", default="none") yield Rule(style=style)
[docs]class ListElement(MarkdownElement): """A list element.""" @classmethod def create(cls, markdown: "Markdown", node: Any) -> "ListElement": list_data = node.list_data return cls(list_data["type"], list_data["start"]) def __init__(self, list_type: str, list_start: Optional[int]) -> None: self.items: List[ListItem] = [] self.list_type = list_type self.list_start = list_start
[docs] def on_child_close( self, context: "MarkdownContext", child: "MarkdownElement" ) -> bool: assert isinstance(child, ListItem) self.items.append(child) return False
def __rich_console__( self, console: Console, options: ConsoleOptions ) -> RenderResult: if self.list_type == "bullet": for item in self.items: yield from item.render_bullet(console, options) else: number = 1 if self.list_start is None else self.list_start last_number = number + len(self.items) for item in self.items: yield from item.render_number(console, options, number, last_number) number += 1
[docs]class ListItem(TextElement): """An item in a list.""" style_name = "markdown.item" def __init__(self) -> None: self.elements: Renderables = Renderables()
[docs] def on_child_close( self, context: "MarkdownContext", child: "MarkdownElement" ) -> bool: self.elements.append(child) return False
def render_bullet(self, console: Console, options: ConsoleOptions) -> RenderResult: render_options = options.update(width=options.max_width - 3) lines = console.render_lines(self.elements, render_options, style=self.style) bullet_style = console.get_style("markdown.item.bullet", default="none") bullet = Segment(" • ", bullet_style) padding = Segment(" " * 3, bullet_style) new_line = Segment("\n") for first, line in loop_first(lines): yield bullet if first else padding yield from line yield new_line def render_number( self, console: Console, options: ConsoleOptions, number: int, last_number: int ) -> RenderResult: number_width = len(str(last_number)) + 2 render_options = options.update(width=options.max_width - number_width) lines = console.render_lines(self.elements, render_options, style=self.style) number_style = console.get_style("markdown.item.number", default="none") new_line = Segment("\n") padding = Segment(" " * number_width, number_style) numeral = Segment(f"{number}".rjust(number_width - 1) + " ", number_style) for first, line in loop_first(lines): yield numeral if first else padding yield from line yield new_line
[docs]class ImageItem(TextElement): """Renders a placeholder for an image.""" new_line = False
[docs] @classmethod def create(cls, markdown: "Markdown", node: Any) -> "MarkdownElement": """Factory to create markdown element, Args: markdown (Markdown): THe parent Markdown object. node (Any): A node from Pygments. Returns: MarkdownElement: A new markdown element """ return cls(node.destination, markdown.hyperlinks)
def __init__(self, destination: str, hyperlinks: bool) -> None: self.destination = destination self.hyperlinks = hyperlinks self.link: Optional[str] = None super().__init__()
[docs] def on_enter(self, context: "MarkdownContext") -> None: self.link = context.current_style.link self.text = Text(justify="left") super().on_enter(context)
def __rich_console__( self, console: Console, options: ConsoleOptions ) -> RenderResult: link_style = Style(link=self.link or self.destination or None) title = self.text or Text(self.destination.strip("/").rsplit("/", 1)[-1]) if self.hyperlinks: title.stylize(link_style) yield Text.assemble("🌆 ", title, " ", end="")
[docs]class MarkdownContext: """Manages the console render state.""" def __init__( self, console: Console, options: ConsoleOptions, style: Style, inline_code_lexer: Optional[str] = None, inline_code_theme: str = "monokai", ) -> None: self.console = console self.options = options self.style_stack: StyleStack = StyleStack(style) self.stack: Stack[MarkdownElement] = Stack() self._syntax: Optional[Syntax] = None if inline_code_lexer is not None: self._syntax = Syntax("", inline_code_lexer, theme=inline_code_theme) @property def current_style(self) -> Style: """Current style which is the product of all styles on the stack.""" return self.style_stack.current
[docs] def on_text(self, text: str, node_type: str) -> None: """Called when the parser visits text.""" if node_type in "code" and self._syntax is not None: highlight_text = self._syntax.highlight(text) highlight_text.rstrip() self.stack.top.on_text( self, Text.assemble(highlight_text, style=self.style_stack.current) ) else: self.stack.top.on_text(self, text)
[docs] def enter_style(self, style_name: Union[str, Style]) -> Style: """Enter a style context.""" style = self.console.get_style(style_name, default="none") self.style_stack.push(style) return self.current_style
[docs] def leave_style(self) -> Style: """Leave a style context.""" style = self.style_stack.pop() return style
[docs]class Markdown(JupyterMixin): """A Markdown renderable. Args: markup (str): A string containing markdown. code_theme (str, optional): Pygments theme for code blocks. Defaults to "monokai". justify (JustifyMethod, optional): Justify value for paragraphs. Defaults to None. style (Union[str, Style], optional): Optional style to apply to markdown. hyperlinks (bool, optional): Enable hyperlinks. Defaults to ``True``. inline_code_lexer: (str, optional): Lexer to use if inline code highlighting is enabled. Defaults to None. inline_code_theme: (Optional[str], optional): Pygments theme for inline code highlighting, or None for no highlighting. Defaults to None. """ elements: ClassVar[Dict[str, Type[MarkdownElement]]] = { "paragraph": Paragraph, "heading": Heading, "code_block": CodeBlock, "block_quote": BlockQuote, "thematic_break": HorizontalRule, "list": ListElement, "item": ListItem, "image": ImageItem, } inlines = {"emph", "strong", "code", "strike"} def __init__( self, markup: str, code_theme: str = "monokai", justify: Optional[JustifyMethod] = None, style: Union[str, Style] = "none", hyperlinks: bool = True, inline_code_lexer: Optional[str] = None, inline_code_theme: Optional[str] = None, ) -> None: self.markup = markup parser = Parser() self.parsed = parser.parse(markup) self.code_theme = code_theme self.justify: Optional[JustifyMethod] = justify self.style = style self.hyperlinks = hyperlinks self.inline_code_lexer = inline_code_lexer self.inline_code_theme = inline_code_theme or code_theme def __rich_console__( self, console: Console, options: ConsoleOptions ) -> RenderResult: """Render markdown to the console.""" style = console.get_style(self.style, default="none") options = options.update(height=None) context = MarkdownContext( console, options, style, inline_code_lexer=self.inline_code_lexer, inline_code_theme=self.inline_code_theme, ) nodes = self.parsed.walker() inlines = self.inlines new_line = False for current, entering in nodes: node_type = current.t if node_type in ("html_inline", "html_block", "text"): context.on_text(current.literal.replace("\n", " "), node_type) elif node_type == "linebreak": if entering: context.on_text("\n", node_type) elif node_type == "softbreak": if entering: context.on_text(" ", node_type) elif node_type == "link": if entering: link_style = console.get_style("markdown.link", default="none") if self.hyperlinks: link_style += Style(link=current.destination) context.enter_style(link_style) else: context.leave_style() if not self.hyperlinks: context.on_text(" (", node_type) style = Style(underline=True) + console.get_style( "markdown.link_url", default="none" ) context.enter_style(style) context.on_text(current.destination, node_type) context.leave_style() context.on_text(")", node_type) elif node_type in inlines: if current.is_container(): if entering: context.enter_style(f"markdown.{node_type}") else: context.leave_style() else: context.enter_style(f"markdown.{node_type}") if current.literal: context.on_text(current.literal, node_type) context.leave_style() else: element_class = self.elements.get(node_type) or UnknownElement if current.is_container(): if entering: element = element_class.create(self, current) context.stack.push(element) element.on_enter(context) else: element = context.stack.pop() if context.stack: if context.stack.top.on_child_close(context, element): if new_line: yield Segment("\n") yield from console.render(element, context.options) element.on_leave(context) else: element.on_leave(context) else: element.on_leave(context) yield from console.render(element, context.options) new_line = element.new_line else: element = element_class.create(self, current) context.stack.push(element) element.on_enter(context) if current.literal: element.on_text(context, current.literal.rstrip()) context.stack.pop() if context.stack.top.on_child_close(context, element): if new_line: yield Segment("\n") yield from console.render(element, context.options) element.on_leave(context) else: element.on_leave(context) new_line = element.new_line
if __name__ == "__main__": # pragma: no cover import argparse import sys parser = argparse.ArgumentParser( description="Render Markdown to the console with Rich" ) parser.add_argument( "path", metavar="PATH", help="path to markdown file, or - for stdin", ) parser.add_argument( "-c", "--force-color", dest="force_color", action="store_true", default=None, help="force color for non-terminals", ) parser.add_argument( "-t", "--code-theme", dest="code_theme", default="monokai", help="pygments code theme", ) parser.add_argument( "-i", "--inline-code-lexer", dest="inline_code_lexer", default=None, help="inline_code_lexer", ) parser.add_argument( "-y", "--hyperlinks", dest="hyperlinks", action="store_true", help="enable hyperlinks", ) parser.add_argument( "-w", "--width", type=int, dest="width", default=None, help="width of output (default will auto-detect)", ) parser.add_argument( "-j", "--justify", dest="justify", action="store_true", help="enable full text justify", ) parser.add_argument( "-p", "--page", dest="page", action="store_true", help="use pager to scroll output", ) args = parser.parse_args() from rich.console import Console if args.path == "-": markdown_body = sys.stdin.read() else: with open(args.path, "rt", encoding="utf-8") as markdown_file: markdown_body = markdown_file.read() markdown = Markdown( markdown_body, justify="full" if args.justify else "left", code_theme=args.code_theme, hyperlinks=args.hyperlinks, inline_code_lexer=args.inline_code_lexer, ) if args.page: import pydoc import io console = Console( file=io.StringIO(), force_terminal=args.force_color, width=args.width ) console.print(markdown) pydoc.pager(console.file.getvalue()) # type: ignore else: console = Console(force_terminal=args.force_color, width=args.width) console.print(markdown)