Reading the required variables for a function

Is there a function that will read the number and names of variables needed to run a function. I'm working on a brute force solution now that just opens the function as a text file and searches for the function declaration then reads the strings between the parenthesis.

[Azzi Abdelmalek]

Do you want the number of variables or their names?

[Adam]

Both, your answer is a viable option, but I don't see how it will read the variables if the function call is not the first line of the .m file.

Answer 1

[Azzi Abdelmalek]

fid = fopen('file.m');
line=''
while isempty(line)
  line=fgetl(fid)
end
fclose(fid);
v=regexp(line,'(?<=\().+(?=\))','match')
n=strfind(v{1},',')  % number of variables

%If you want their names

w=regexp(v{1},',','split')

[Adam]

This is great unless the function call is not on the first line of the code.

[Azzi Abdelmalek]

the test while isempty(line) checks if the first lines are empty

[Walter Roberson]

Remember comment lines, and comments more generally.

Watch out for continuation lines.

[Azzi Abdelmalek]

For comment we can add a test

if line(1)=='%'
      line=''
end

[Walter Roberson]

Comments can start anywhere on a line. Also, blanks are permitted on lines.

line = regexprep(line, {'%.*', '^s+'}, {'', ''});

[Azzi Abdelmalek]

The first character of line is always different from ' '

Answer 2

[Image Analyst]

Maybe take a look at this: http://www.mathworks.com/matlabcentral/fileexchange/17291-fdep-a-pedestrian-function-dependencies-finder

Answer 3

[Adam]

Thanks for the help Azzi. I never used the regexp function before. It works really well in this application.

function [nvars,vars] = req_variables(filename)

% % Open the file for reading only.

[fid,msg] = fopen(filename,'r');

if fid <= 0

    disp('Was not able to open file');
    disp(msg)
    return;
end

% Read the file, line by line, until we find the function call

line = ' ';

while (~strcmp(line(1:8),'function'))

    line = fgetl(fid);
end

% Read the variable names and number from the line

v=regexp(line,'(?<=\().+(?=\))','match');

nvars =strfind(v{1},','); % number of variables

vars=regexp(v{1},',','split');

%Close the file

fclose(fid);