Pandoc UI

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Useful Links

Name	URL
Pandoc User’s Guide	https://pandoc.org/MANUAL.html

import streamlit as st
import re
import os
import subprocess

Print banner.

@st.cache_data
def print_banner():
    print("""
                                ,--.                            ,--.
       ,---.  ,--,--.,--,--,  ,-|  | ,---.  ,---.,-----.,--.,--.`--'
      | .-. |' ,-.  ||      \\' .-. || .-. || .--''-----'|  ||  |,--.
      | '-' '\\ '-'  ||  ||  |\\ `-' |' '-' '\\ `--.       '  ''  '|
      |  |-'  `--`--'`--''--' `---'  `---'  `---'        `----' `--'
      `--'

    """)
    return 1

print_banner()

Input and output formats.

ext_names = {
    ".md": "Markdown",
    ".rst": "ReST",
    ".adoc": "AsciiDoc"
}

def ext_name(name):
    return ext_names[name]

i_ext = st.sidebar.radio(
    "Input format",
    options = [".md", ".rst"],
    format_func = ext_name,
)

o_ext = st.sidebar.radio(
    "Output format",
    options = [".rst", ".adoc"],
    format_func = ext_name,
)

Checks if output_folder exists in the user’s home directory.

home_directory = os.path.expanduser("~")
output_folder = os.path.join(home_directory, ".a-services")
if not os.path.exists(output_folder):
    os.makedirs(output_folder)

temp_name = "pan_ui"
input_file = os.path.join(output_folder, temp_name + i_ext)
output_file = os.path.join(output_folder, temp_name + o_ext)

When converting from ReST to Asciidoc using the Pandoc tool, the code snippets are surrounded by dots. We can use a custom Lua filter in Pandoc to transform the code blocks into the desired format.

custom_codeblock = """
function CodeBlock(el)
    local code = el.text
    local lang = el.classes[1] or "python" -- Get the first class as the language
    if lang ~= "" then
        return pandoc.RawBlock('asciidoc', '```' .. lang .. '\\n' .. code .. '\\n```\\n\\n')
    else
        return pandoc.RawBlock('asciidoc', '```\\n' .. code .. '\\n```\\n\\n')
    end
end
"""

lua_codeblock_file = os.path.join(output_folder, "custom_codeblock.lua")
with open(lua_codeblock_file, "w", encoding="utf-8") as fout:
    fout.write(custom_codeblock)

lua_filter = "--lua-filter=" + lua_codeblock_file

Convert text.

text_area_height = 250

text = st.text_area("Input text", height = text_area_height)

def run_pandoc(input_file, output_file):
    with open(input_file, "w", encoding="utf-8") as fout:
        fout.write(text)

    if i_ext == ".md":
        subprocess.run(["pandoc", "-f", "gfm", "-s", input_file, "-o", output_file], check=True)
    elif o_ext == ".adoc":
        subprocess.run(["pandoc", lua_filter, "-s", input_file, "-o", output_file], check=True)
    else:
        subprocess.run(["pandoc", "-s", input_file, "-o", output_file], check=True)

    with open(output_file, "r", encoding="utf-8") as fin:
        result = fin.read()

    return result

def convert_text():

    result = run_pandoc(input_file, output_file)
    if o_ext == ".adoc":
        result = asciidoc_headers(result)

    st.text_area(label = "Output text", value = result, height = text_area_height)

Remove lines that contain Pandoc’s anchor markup: [[something]]

def asciidoc_headers(content):
    # This will remove the entire line if it matches, including the newline.
    cleaned_content = re.sub(r'^\[\[.*?\]\]\s*\n', '', content, flags=re.MULTILINE)
    return cleaned_content

Click button.

st.sidebar.write('---')
if st.sidebar.button('Convert', type='primary'):
    if i_ext == o_ext:
        st.error("Input and output formats shouldn't be the same!")
    elif text is None or text.strip() == '':
        st.error("Input text is empty!")
    else:
        convert_text()