How to underline an undefined function or variable

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Heorhii Koltsov
Heorhii Koltsov 2018-10-5
评论： Heorhii Koltsov 2018-10-8
Hi,
I am curious if there is a way to configure Matlab to show an undefined function or variable before running a script. For example, I want the following code to be executed if variable "a" is defined, otherwise I get notification that "a" is not set before pressing "F5".
if a>1
b=2;
end
Is there a way to configure this, maybe in Matlab code analyzer?
  2 个评论
Stephen23
Stephen23 2018-10-5
编辑：Stephen23 2018-10-5
It is easy for code to change the MATLAB Search Path while running, to run scripts and call functions which change/define/clear variables in the workspace, and to overload almost any operator. There is no way to know what code will resolve to and what variables it actually has, until it is run.
That is simple a side effect of a dynamically typed language which is parsed on the fly. It is in the very nature of such a language.
Heorhii Koltsov
Heorhii Koltsov 2018-10-8
I read that there is pylint for Python which is checking the code statically and I think it will also check for the variables

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采纳的回答

John D'Errico
John D'Errico 2018-10-5
I believe that capability would not exist, because it is easy enough to create a variable or function name on the fly. It would be terribly poor coding practice to do so, but you CAN do it.
A quick check in the editor preferences did not show such a flag.

更多回答（1 个）

Image Analyst
Image Analyst 2018-10-5
There is a not very practical way. You could do
if exist('a', 'var')
if a>1
b=2;
end
else
uiwait(errordlg('a does not exist'));
end
But you really don't want to do that for every variable in your program. Anyway, if you knew to check for it, then you'd know to assign it. There is no automatic way to do it before running your program. However sometimes the mlint will tell you that a variable is being used before it's assigned with a orange squiggly underline, but it doesn't always detect that.
  1 个评论
Heorhii Koltsov
Heorhii Koltsov 2018-10-8
Yeah that's correct. I read about exist function but of course it would be painful to write it for each variable. I guess the problem is that I am not using matlab correctly that's why I have such question :)

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