EVALIN cannot execute a return?
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I am trying to create a function that aborts whatever mfile is currently executing after issuing a warning. I see no way of avoiding EVALIN for this and so implemented the following,
function abort_and_warn
warning 'Aborting'
evalin('caller', 'return');
end
However, a simple test of this code in R2020a,
function test
disp 'do this'
abort_and_warn
disp 'do that'
end
fails to block the execution of the final line:
>> test
do this
Warning: Aborting
> In test>abort_and_warn (line 12)
In test (line 5)
do that
Is this an undocumented limitation of EVALIN? I see nothing here to imply that EVALIN should be unable to issue the return command in the caller wokspace.
댓글 수: 4
Bruno Luong
2020년 8월 7일
A simple EVAL('RETURN') is not execute either
function foo
eval('return');
fprintf('this will be printed out\n');
end
>> foo
this will be printed out
>>
채택된 답변
Bruno Luong
2020년 8월 7일
편집: Bruno Luong
2020년 8월 7일
Yes it is written in the doc.
From EVALIN/EVAL document page
...
expression — Expression to evaluate
character vector | string scalar
Expression to evaluate, specified as a character vector or string scalar. expression must be a valid MATLAB expression and must not include any MATLAB keywords."
>> iskeyword('return')
ans =
logical
1
댓글 수: 1
Bruno Luong
2020년 8월 7일
편집: Bruno Luong
2020년 8월 7일
However
eval('global foo')
works and global is a keyword.Go figure....
That exposes few of the hidden paradoxal gems of MATLAB.
추가 답변 (1개)
Fangjun Jiang
2020년 8월 7일
It seems that "return" was not executed in the "caller" workspace as it is supposed to by evalin().
But would a "regular" approach work by passing some kind of flag or value?
In function abort_and_warn, return with a flag or a special value after issuing the warning.
In function test, check the return value of function abort_and_warn, then execute return.
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