84 lines
2.6 KiB
Python
84 lines
2.6 KiB
Python
"""
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Mermaid Extension for Python-Markdown
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========================================
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Adds mermaid parser (like github-markdown) to standard Python-Markdown code blocks.
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Original code Copyright 2018-2020 [Olivier Ruelle].
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License: GNU GPLv3
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"""
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from markdown.extensions import Extension
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from markdown.preprocessors import Preprocessor
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import re
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import os
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MermaidRegex = re.compile(r"^(?P<mermaid_sign>[\~\`]){3}[\ \t]*[Mm]ermaid[\ \t]*$")
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# ------------------ The Markdown Extension -------------------------------
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class MermaidPreprocessor(Preprocessor):
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def run(self, lines):
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new_lines = []
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mermaid_sign = ""
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m_start = None
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m_end = None
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in_mermaid_code = False
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is_mermaid = False
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old_line = ""
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js_file = "file://" + (os.path.join(os.path.dirname(__file__), "node_modules", "mermaid", "dist", "mermaid.js"))
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new_lines.append('<meta charset="utf-8">')
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new_lines.append('<script src="{}"></script>'.format(js_file))
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new_lines.append('<script>mermaid.initialize({startOnLoad:true});</script>')
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for line in lines:
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# Wait for starting line with MermaidRegex (~~~ or ``` following by [mM]ermaid )
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if not in_mermaid_code:
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m_start = MermaidRegex.match(line)
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else:
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m_end = re.match(r"^["+mermaid_sign+"]{3}[\ \t]*$", line)
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if m_end:
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in_mermaid_code = False
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if m_start:
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in_mermaid_code = True
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mermaid_sign = m_start.group("mermaid_sign")
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if not re.match(r"^[\ \t]*$", old_line):
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new_lines.append("")
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if not is_mermaid:
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is_mermaid = True
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new_lines.append('<div class="mermaid">')
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m_start = None
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elif m_end:
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new_lines.append('</div>')
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new_lines.append("")
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m_end = None
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elif in_mermaid_code:
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new_lines.append(line.strip())
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else:
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new_lines.append(line)
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old_line = line
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return new_lines
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class MermaidExtension(Extension):
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""" Add source code hilighting to markdown codeblocks. """
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def extendMarkdown(self, md, md_globals):
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""" Add HilitePostprocessor to Markdown instance. """
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# Insert a preprocessor before ReferencePreprocessor
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md.preprocessors.register(MermaidPreprocessor(md), 'mermaid', 35)
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md.registerExtension(self)
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def makeExtension(**kwargs): # pragma: no cover
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return MermaidExtension(**kwargs)
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