get_cpp_from_ipynb.py

import os
import nbformat
import sys
import re
import tempfile


def has_gpp():
    """
    Check if this system has g++ compiler
    """
    result = os.system('bash which g++')
    print(f"has_gpp() result = {result}")
    return not (result)


def is_markdown_cpp_src(ipynb_cell):
    """
    True if a cell is markdown && multiline source code && C++

    ```'s wrap multiline code blocks
    C++ source code blocks have C++ right after starting ```
    """
    result = False

    # Markdown
    if 'markdown' == ipynb_cell['cell_type']:
        src = ipynb_cell['source'].strip()

        # Multiline code block within ```'s
        if (src.startswith('```')
            and src.endswith('```')):

            # check C++ right after ```
            if "c++" in src.splitlines()[0].lower():
                result = True

    return result


def get_main_function_pattern():
    return re.compile(r'^[A-Za-z]\w*\s+main\s*\(', re.M)


def get_filename_in_second_line(cpp_txt):
    """
    From the second line of cpp_txt, get the filename

    Expected input argument:
    // ```
    // Begin file_name.cpp
    // ...

    Expected output argument in this case:
    file_name.cpp
    """

    result = ""

    for line in cpp_txt.splitlines():
        if line.strip().lower().startswith('//'):
            # ignore if too short
            if 2 < len(line.lower().split()):
                # If second word is 'begin'
                if 'begin' == line.lower().split()[1]:
                    result = line.lower().split()[-1]
                    break

    return result


re_main_function = get_main_function_pattern()


def get_build_command_in_last_line(cpp_txt):
    """
    From the last line of cpp_txt, get the build command

    Expected input argument:
    // ...
    // End account_module_user.cpp
    // Build command : g++ -Wall -g account_module.cpp account_module_user.cpp
    // ```

    Expected output argument in this case:
    "g++ -Wall -g account_module.cpp account_module_user.cpp"
    """

    result = ""

    # Starting from the last line.
    cpp_lines = cpp_txt.splitlines()
    cpp_lines.reverse()

    # Source code loop
    for line in cpp_lines:
        # Check comment lines only
        if line.strip().lower().startswith('//'):
            # ignore if too short
            if 4 < len(line.lower().split()):
                # Check words
                if (
                    ('build' == line.lower().split()[1])
                    and ('command' == line.lower().split()[2])
                    and (':' == line.lower().split()[3])
                ):
                    # reassemble compile command
                    result = ' '.join(line.split()[4:])
                    break

    return result


def build_markdown_cpp_cell(ipynb_cell):
    """
    Save the C++ source code and try to build it
    """
    # Comment out ```'s
    txt = ipynb_cell['source'].replace('```', '// ```')

    cpp_file_name = get_filename_in_second_line(txt)

    if not cpp_file_name:
        # obtain temporary file name
        cpp_file_name = get_temp_cpp_filename()

    cpp_file_basename, _ = os.path.splitext(cpp_file_name)

    # open the temporary file and write to it
    with open(cpp_file_name, 'wt') as cpp_file:
        cpp_file.write(txt)

    # Build the code
    # Complex literal example needs C++ 14
    # https://www.linuxquestions.org/questions/programming-9/trouble-with-double-complex-numbers-in-c-4175567740/
    # https://stackoverflow.com/questions/31965413/compile-c14-code-with-g

    if re_main_function.findall(txt):
        # if txt includes the main() function, build execution file

        # if the C++ source code seems to have build command, use it
        if "\n// build command" in txt.lower():
            compile_command = get_build_command_in_last_line(txt)
        else:
            compile_command = ""

        if not compile_command:
            compile_command = f"g++ -Wall -g -std=c++14 {cpp_file_name} -o {cpp_file_basename}"

        compile_result = os.system(compile_command)
        run_result = os.system(os.path.join(os.curdir, cpp_file_basename))

        result = (compile_result or run_result)
    else:
        # if txt does not include main() function, just check grammar
        compile_command = f"g++ -Wall -g -std=c++14 {cpp_file_name} -fsyntax-only"

        result = os.system(compile_command)

    # Delete the execution file
    if os.path.exists(cpp_file_basename):
        os.remove(cpp_file_basename)

    result_dict = {
        'result': result,
        'cpp_filename': cpp_file_name,
    }

    return result_dict


def get_temp_cpp_filename():
    """
    Generate a temporary filename
    """
    # obtain temporary file name
    with tempfile.NamedTemporaryFile(suffix=".cpp", mode='wt') as cpp_file:
        cpp_file_name = cpp_file.name
    return cpp_file_name


def get_cpp_src_from_ipynb(path):
    """
    Get cpp source code from markdown cells of the ipynb file

    To test C++ source codes of the documents

    + Choose markdown cells
    + Choose C++ source code cells
    + Save to a temporary file and try to build
    """
    with open(path, encoding='utf-8') as ipynb:
        nb = nbformat.read(ipynb, nbformat.NO_CONVERT)

    # choose markdown cells with C++ source code only
    markdown_cpp_code_cells = filter(
        is_markdown_cpp_src,
        nb['cells']
    )

    # save the C++ source code and try to build it
    return map_build_run_over_markdown_cpp_cells(markdown_cpp_code_cells)


def map_build_run_over_markdown_cpp_cells(markdown_cpp_code_cells):
    # save the C++ source code and try to build it
    results_map = map(build_markdown_cpp_cell, markdown_cpp_code_cells)

    results_list = []
    files_to_delete_list = []

    for d in results_map:
        cpp_file_name = d['cpp_filename']
        results_list.append(d['result'])
        files_to_delete_list.append(cpp_file_name)

    for cpp_file_name in files_to_delete_list:
        # Delete the temporary cpp source file
        if os.path.exists(cpp_file_name):
            os.remove(cpp_file_name)

    return not(any(results_list))


def main(arg):
    print('return value = ', get_cpp_src_from_ipynb(arg[0]))


if "__main__" == __name__:
    if 2 < len(sys.argv):
        main(sys.argv[1:])
    else:

        ipynb_00 = os.path.abspath(
                os.path.join(
                os.path.split(os.path.abspath(__file__))[0],
                os.pardir,
                '00.ipynb',
                )
        )

        if os.path.exists(ipynb_00):
            main([ipynb_00])