forked from varia/varia.website
337 lines
9.7 KiB
Python
337 lines
9.7 KiB
Python
"""
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class Renderer
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Generates HTML from parsed token stream. Each instance has independent
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copy of rules. Those can be rewritten with ease. Also, you can add new
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rules if you create plugin and adds new token types.
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"""
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from __future__ import annotations
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from collections.abc import Sequence
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import inspect
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from typing import Any, ClassVar, Protocol
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from .common.utils import escapeHtml, unescapeAll
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from .token import Token
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from .utils import EnvType, OptionsDict
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class RendererProtocol(Protocol):
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__output__: ClassVar[str]
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def render(
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self, tokens: Sequence[Token], options: OptionsDict, env: EnvType
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) -> Any:
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...
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class RendererHTML(RendererProtocol):
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"""Contains render rules for tokens. Can be updated and extended.
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Example:
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Each rule is called as independent static function with fixed signature:
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::
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class Renderer:
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def token_type_name(self, tokens, idx, options, env) {
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# ...
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return renderedHTML
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::
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class CustomRenderer(RendererHTML):
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def strong_open(self, tokens, idx, options, env):
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return '<b>'
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def strong_close(self, tokens, idx, options, env):
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return '</b>'
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md = MarkdownIt(renderer_cls=CustomRenderer)
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result = md.render(...)
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See https://github.com/markdown-it/markdown-it/blob/master/lib/renderer.js
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for more details and examples.
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"""
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__output__ = "html"
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def __init__(self, parser: Any = None):
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self.rules = {
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k: v
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for k, v in inspect.getmembers(self, predicate=inspect.ismethod)
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if not (k.startswith("render") or k.startswith("_"))
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}
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def render(
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self, tokens: Sequence[Token], options: OptionsDict, env: EnvType
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) -> str:
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"""Takes token stream and generates HTML.
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:param tokens: list on block tokens to render
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:param options: params of parser instance
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:param env: additional data from parsed input
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"""
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result = ""
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for i, token in enumerate(tokens):
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if token.type == "inline":
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if token.children:
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result += self.renderInline(token.children, options, env)
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elif token.type in self.rules:
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result += self.rules[token.type](tokens, i, options, env)
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else:
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result += self.renderToken(tokens, i, options, env)
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return result
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def renderInline(
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self, tokens: Sequence[Token], options: OptionsDict, env: EnvType
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) -> str:
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"""The same as ``render``, but for single token of `inline` type.
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:param tokens: list on block tokens to render
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:param options: params of parser instance
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:param env: additional data from parsed input (references, for example)
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"""
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result = ""
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for i, token in enumerate(tokens):
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if token.type in self.rules:
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result += self.rules[token.type](tokens, i, options, env)
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else:
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result += self.renderToken(tokens, i, options, env)
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return result
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def renderToken(
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self,
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tokens: Sequence[Token],
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idx: int,
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options: OptionsDict,
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env: EnvType,
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) -> str:
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"""Default token renderer.
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Can be overridden by custom function
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:param idx: token index to render
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:param options: params of parser instance
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"""
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result = ""
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needLf = False
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token = tokens[idx]
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# Tight list paragraphs
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if token.hidden:
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return ""
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# Insert a newline between hidden paragraph and subsequent opening
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# block-level tag.
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#
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# For example, here we should insert a newline before blockquote:
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# - a
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# >
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#
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if token.block and token.nesting != -1 and idx and tokens[idx - 1].hidden:
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result += "\n"
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# Add token name, e.g. `<img`
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result += ("</" if token.nesting == -1 else "<") + token.tag
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# Encode attributes, e.g. `<img src="foo"`
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result += self.renderAttrs(token)
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# Add a slash for self-closing tags, e.g. `<img src="foo" /`
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if token.nesting == 0 and options["xhtmlOut"]:
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result += " /"
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# Check if we need to add a newline after this tag
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if token.block:
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needLf = True
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if token.nesting == 1 and (idx + 1 < len(tokens)):
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nextToken = tokens[idx + 1]
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if nextToken.type == "inline" or nextToken.hidden: # noqa: SIM114
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# Block-level tag containing an inline tag.
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#
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needLf = False
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elif nextToken.nesting == -1 and nextToken.tag == token.tag:
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# Opening tag + closing tag of the same type. E.g. `<li></li>`.
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#
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needLf = False
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result += ">\n" if needLf else ">"
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return result
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@staticmethod
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def renderAttrs(token: Token) -> str:
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"""Render token attributes to string."""
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result = ""
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for key, value in token.attrItems():
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result += " " + escapeHtml(key) + '="' + escapeHtml(str(value)) + '"'
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return result
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def renderInlineAsText(
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self,
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tokens: Sequence[Token] | None,
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options: OptionsDict,
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env: EnvType,
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) -> str:
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"""Special kludge for image `alt` attributes to conform CommonMark spec.
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Don't try to use it! Spec requires to show `alt` content with stripped markup,
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instead of simple escaping.
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:param tokens: list on block tokens to render
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:param options: params of parser instance
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:param env: additional data from parsed input
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"""
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result = ""
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for token in tokens or []:
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if token.type == "text":
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result += token.content
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elif token.type == "image":
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if token.children:
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result += self.renderInlineAsText(token.children, options, env)
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elif token.type == "softbreak":
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result += "\n"
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return result
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###################################################
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def code_inline(
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self, tokens: Sequence[Token], idx: int, options: OptionsDict, env: EnvType
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) -> str:
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token = tokens[idx]
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return (
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"<code"
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+ self.renderAttrs(token)
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+ ">"
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+ escapeHtml(tokens[idx].content)
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+ "</code>"
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)
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def code_block(
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self,
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tokens: Sequence[Token],
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idx: int,
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options: OptionsDict,
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env: EnvType,
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) -> str:
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token = tokens[idx]
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return (
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"<pre"
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+ self.renderAttrs(token)
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+ "><code>"
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+ escapeHtml(tokens[idx].content)
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+ "</code></pre>\n"
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)
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def fence(
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self,
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tokens: Sequence[Token],
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idx: int,
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options: OptionsDict,
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env: EnvType,
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) -> str:
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token = tokens[idx]
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info = unescapeAll(token.info).strip() if token.info else ""
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langName = ""
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langAttrs = ""
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if info:
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arr = info.split(maxsplit=1)
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langName = arr[0]
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if len(arr) == 2:
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langAttrs = arr[1]
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if options.highlight:
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highlighted = options.highlight(
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token.content, langName, langAttrs
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) or escapeHtml(token.content)
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else:
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highlighted = escapeHtml(token.content)
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if highlighted.startswith("<pre"):
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return highlighted + "\n"
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# If language exists, inject class gently, without modifying original token.
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# May be, one day we will add .deepClone() for token and simplify this part, but
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# now we prefer to keep things local.
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if info:
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# Fake token just to render attributes
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tmpToken = Token(type="", tag="", nesting=0, attrs=token.attrs.copy())
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tmpToken.attrJoin("class", options.langPrefix + langName)
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return (
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"<pre><code"
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+ self.renderAttrs(tmpToken)
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+ ">"
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+ highlighted
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+ "</code></pre>\n"
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)
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return (
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"<pre><code"
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+ self.renderAttrs(token)
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+ ">"
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+ highlighted
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+ "</code></pre>\n"
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)
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def image(
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self,
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tokens: Sequence[Token],
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idx: int,
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options: OptionsDict,
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env: EnvType,
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) -> str:
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token = tokens[idx]
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# "alt" attr MUST be set, even if empty. Because it's mandatory and
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# should be placed on proper position for tests.
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if token.children:
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token.attrSet("alt", self.renderInlineAsText(token.children, options, env))
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else:
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token.attrSet("alt", "")
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return self.renderToken(tokens, idx, options, env)
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def hardbreak(
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self, tokens: Sequence[Token], idx: int, options: OptionsDict, env: EnvType
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) -> str:
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return "<br />\n" if options.xhtmlOut else "<br>\n"
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def softbreak(
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self, tokens: Sequence[Token], idx: int, options: OptionsDict, env: EnvType
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) -> str:
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return (
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("<br />\n" if options.xhtmlOut else "<br>\n") if options.breaks else "\n"
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)
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def text(
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self, tokens: Sequence[Token], idx: int, options: OptionsDict, env: EnvType
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) -> str:
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return escapeHtml(tokens[idx].content)
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def html_block(
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self, tokens: Sequence[Token], idx: int, options: OptionsDict, env: EnvType
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) -> str:
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return tokens[idx].content
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def html_inline(
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self, tokens: Sequence[Token], idx: int, options: OptionsDict, env: EnvType
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) -> str:
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return tokens[idx].content
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