What happened to eval function?

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KAE on 15 Jun 2022
Commented: Walter Roberson on 18 Jun 2022
I am using R2022a, and the eval function is giving me an error,
eval(['4 + 5'])
ans = 9
Unrecognized function or variable 'eval'.
Ignore "ans = 9" in my question, since that's what happened when I ran it online in R2022a; that is the expected behavior but not what I'm getting on my computer.
Any idea what's going on? I tried restarting Matlab and the error persisted.
KAE on 17 Jun 2022
>> which -all eval
built-in (C:\Program Files\MATLAB\R2022a\toolbox\matlab\lang\eval)
C:\Program Files\MATLAB\R2022a\toolbox\matlab\lang\@opaque\eval.m % opaque method
C:\Users\MyName\OneDrive - datacolor\matlab_programs\data processing\fdaM\@bifd\eval.m % bifd method

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Accepted Answer

Walter Roberson
Walter Roberson on 16 Jun 2022
I think maybe you could get this error under the odd conditions:
  • you are inside a function
  • you assign to a variable named eval
  • you run a script
  • the script clears the variable named eval
  • after the script you try to use eval
I am not positive this will generate that exact error, but MATLAB is allowed to lose track of functions and variables if you do this or you assign to a name inside the script when the name matches a function name
Walter Roberson
Walter Roberson on 18 Jun 2022
I have to admit that using "syms" is very convenient, especially for creating symbolic functions or arrays of symbols. syms in that form is implemented as assignin('caller') which is a case of creating variables based upon string.

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