Old method of publishing code with line numbers to html is broken in MATLAB R2021. What is the new method?

We use "publish" to store reports of generated MATLAB code, and we used the line-numbering technique shown here: How can I print line numbers when I use the PUBLISH command in MATLAB?

However, MATLAB R2021b appears to be using the lint/parser to publish the code, so adding text at the beginning generates a syntax error. The current documentation still does not support a feature to enumerate the code lines: publish

So, is there a new techique to inject line numbers in the resulting html report of the source file?

Answer 1

[Narvik]

Hi,

As per my understanding, you are trying to add line numbers to the code blocks in the HTML report generated using ‘publish’ method. As you mentioned, the current ‘publish’ function does not support a feature to enumerate the code lines.

One straightforward way is to manually inject line numbers into the HTML report generated using the ‘publish’ function. You can try to write a script to automate this.

Another way is to try using part of the custom function suggested in the MATLAB answer: https://www.mathworks.com/matlabcentral/answers/92096-how-can-i-print-line-numbers-when-i-use-the-publish-command-in-matlab along with the ‘export’ MATLAB function. Refer to the modified function below:

function mypublish(filename) 
    % A Custom publish function that includes the line 
    % number for each line in the function 
    % Usage: addLineNumbers('myfun.m') 
    copyfile(filename, 'mytemp.m', 'f') 
    fid1 = fopen(filename); 
    fid2 = fopen('mytemp.m', 'w'); 
    i=1; 
    while 1 
        tline = fgetl(fid1); 
        if ~ischar(tline) 
            break; 
        end 
        if ~isempty(tline) 
            tline = [num2str(i),' ', tline]; 
            fprintf(fid2,'%s',tline); 
            fprintf(fid2,'%s\n',''); 
            i = i + 1; 
        end 
    end 
    fclose(fid1); 
    fclose(fid2); 
    % Get file name as string 
    [~,fileName,~] = fileparts(filename); 
    % Convert .m file to .mlx file 
    matlab.internal.liveeditor.openAndSave('mytemp.m', 'mytemp.mlx'); 
    % Generate HTML file from .mlx file with same file name 
    export('mytemp.mlx', strcat(fileName, '.html'), Format="html"); 
    % Remove temporary files 
    delete('mytemp.m'); 
    delete('mytemp.mlx'); 
end 

This function adds line numbers to the code, convert .m file to .mlx file and uses the ‘export’ function to generate HTML file. Note that ‘export’ function was introduced in R2022a. For more information, refer to the following documentation:

https://www.mathworks.com/help/matlab/ref/export.html

Hope this helps!

[James Sorenson]

Did you try this function yourself? It appears to have the exact same issue as the original method: the modified file is no longer valid MATLAB syntax, so the publish/export fails. I copied this verbatim to "mypublish.m" and created a "test_publish.m" file as so:

% Test the mypublish tool
disp('line 2')
disp('line 3')

Then I called mypublish('test_publish.m') in MATLAB R2023b and got the same error I expected:

>> test_publish

line 2

line 3

>> mypublish('test_publish.m')

function_options =

struct with fields:

format: 'html'

Error using matlab.codeanalyzer.internal.analyzeCode

Input code contains one or more syntax errors.

Error in m2mxdom (line 21)

cellLocations = matlab.codeanalyzer.internal.analyzeCode(code);

Error in publish

Error in mypublish (line 29)

publish('mytemp',function_options); % publish temp function with line numbers

Caused by:

Line 2 (Column 3): Parse error at disp: usage might be invalid MATLAB syntax.

This is because the code is modified (shown below) before being parsed, which creates a syntax error on line 2:

1 % Test the mypublish tool
2 disp('line 2')
3 disp('line 3')

Now, we could prefix everything with "%" so that the whole file is just comments, but that would disable most of the best features of the publishing tool. They've implemented some impressive markdown capabilities within the comments, but I'm surprised no developers have yet seen a need to enumerate the file in order to reference warnings or errors. We worked around it with the old method for years, but that no longer works.

This web comments system still highlights the modified code without issue. I guess it's using the old parser?

[Narvik]

Hi @James Sorenson

The modified function avoids using the 'publish' function and uses the new 'export' function. The error message above mentions the use of 'publish' function. Since you mentioned that you copied the provided function into your .m file, ensure :

1. You are using the correct 'mypublish.m' file
2. The 'mypublish.m' file has the modified implementation provided in the above answer
3. The .m file is saved before running the function

Your 'mypublish.m' file seems to be using the previous implementation.

The modified 'mypublish' function publishes code with line numbers into a HTML file. I tried using the 'test_publish.m' as input to 'mypublish' function and got the desired result in a HTML file:

1 % Test the mypublish tool
2 disp('line 2')
3 disp('line 3')

Hope this helps!

[James Sorenson]

My apologies for my rookie mistake, as I should've noticed that from the error. The old mypublish.m was still in the path from the old project folder. I renamed yours to "mypublish2" to make sure I called the correct one. It does indeed work! So, "export" doesn't do the same syntax-check as "publish."

Unfortunately, our project is stuck on MATLAB R2021B due to some Simulink AutoCoder incompaitibilities introduced in R2022, so it looks like we're going to be broken for a while until we resolve that. Thanks for the future solution, though.