How to get .m file definition programmatically?

When looking at the Current Folder pane, the icons let you know if a m-file is a "script", "function", or "class" definition and if a .mlx is a "live script" or "live function". Is there any way to get that information programmatically using a built-in function?

[Dyuman Joshi]

You can read the file name, specifically the extension in the form of a char or a string array and compare it accordingly.

[dpb]

But an m-file can be either a script or a function from starters, so just having the file name is insufficient.

One has to parse the content of the file to know which. The internal interpreter does that so it knows; at the moment I'm unaware of any such user tool that returns that info (although I'm a couple rev's behind and haven't read the release notes for new features).

[Dyuman Joshi]

Check out the FEX submission - isfunction() by Jos (10584)

[Travis Bueter]

For added clarity, my goal is to check if an arbritary .m file contains a class defintion, a function definition, or is a script. As seen in the image above, all 3 .m files have different icons to distinguish their contents. I could write my own text-parser to read the file, strip it of all white space/comments, and then see if it starts with the keywords "classdef" or "function".

Similarly, I would also like to know if an arbritary .mlx file is formatted as a live script or a live function. However, since these are binary files, I'm unsure what metadata to be looking for to distinguish them.

My hope is there is an accessible method (even if undocumented) that does this since MATLAB is capable of distiguishing them in the interface.

[dpb]

Understanding the wish isn't the problem; it's that unless Yair has uncovered and published something recently, there's nothing exposed to the end user that tells you this.

The command window and interpreter have access to all the internals so they can do things such as this not available otherwise.

Now, that there may be something buried deep in the hidden bowels of the private sections...

[Steven Lord]

my goal is to check if an arbritary .m file contains a class defintion, a function definition, or is a script.

How are you planning or hoping to use this information? What do you want to do differently depending on whether the file is a class file, a function file, a script file (and do you care if the script does or does not contain a local function?), or is not a MATLAB code file at all?

[Travis Bueter]

I am working to create a system to do a "health check" of our repositories that is performed by a CI system. Some of the checks include ensuring files are in the correct location (e.g. no scripts in certain folders, classes always in an @ folder when in a package, etc.) and other supplementary files exist (e.g. documentation, test files, etc.), which differ between classes and functions.

Currently I don't need to know if a script contains a local function.

Answer 1

[Sulaymon Eshkabilov]

It is possible differentiate .m and .mlx files by referring to their file extensions or simlarly, Simulink's .mdl and .slx or slxc files by using a wildcard, e.g.

Sm = dir('*.m')            % Locates all M-files in the current directory
Sm.name                    % Names of M-files
numel(Sm)                  % How many M-file
% Similarly, MLX-files
Smlx = dir('*.mlx')
Smlx.name
numel(Smlx)
% Similarly, SLX files
Sslx = dir('*.slx')
Sslx.name
numel(Sslx)

[Travis Bueter]

Thank you for your response! Distinguishing the files by their extension is not the problem I am looking to solve. I added a comment to help clarify what my goal is: https://www.mathworks.com/matlabcentral/answers/1915745-how-to-get-m-file-definition-programmatically#comment_2624560

Answer 2

[Image Analyst]

Try using readlines then removing comments and see if the first line is classdef, function, or something else:

% Define filename.
fileName = 'testRGBImage.m';

% Read in all lines of a file.
allLines = readlines(fileName);
% Get rid of leading white space.
allLines = strtrim(allLines);
% Get rid of all lines that start with a comment.
c = startsWith(allLines, '%');
allLines(c) = [] % Delete lines starting with a comment.

% See if the first line of code is a classdef
itsAClass = contains(allLines{1}, 'classdef')
% See if the first line of code is a function declaration
itsAFunction = contains(allLines{1}, 'function')
% If it's not one of those, then it is a script (which may be followed by internal functions).
itsAScript = ~(itsAClass || itsAFunction)