Within a function : get complete command-line calling text, a la dbstack()..?

조회 수: 21(최근 30일)
Bradley Stiritz
Bradley Stiritz 2011년 9월 25일
댓글: Matthew 2017년 12월 15일
Hi everyone,
I understand how to use dbstack(), within a saved M-function, to get the complete text of the command which called the current function. For example, if we have two M-files, A.m & B.m, where A() calls (B):
FILE 'A.m'
function output = A(input)
output = B(input);
FILE 'B.m'
function output = B(input)
% ---------------------------------------------------------------------
% What line of text called this function..?
% ---------------------------------------------------------------------
% Get call-stack info:
stDebug = dbstack;
% We know a-priori that this function's caller info is in (stDebug)(2)
% Get caller file name & line number of code which called this function:
callerFileName = stDebug(2).file;
callerLineNumber = stDebug(2).line;
% Open caller file:
fCaller = fopen(callerFileName);
% Iterate through lines to get to desired line number:
for iLine = 1 : callerLineNumber
% Read current line of text:
currLine = fgetl(fCaller);
end
% (currLine) now reflects calling desired code: display this code:
fprintf('Complete text of calling code is : ''%s''\n',currLine);
% Close caller file:
fclose(fCaller);
% ---------------------------------------------------------------------
% Determine function output
% ---------------------------------------------------------------------
% Arbitrary operation just for demonstration:
output = input + 5;
If we call A() from the command-line, we get:
>> A(10)
Complete text of calling code is : 'output = B(input);'
ans = 15
However, if we call B() directly from the command-line, we get an error, b/c there is no 2nd element in the dbstack() output. In other words, for this case dbstack() output is a single-element structure containing info for the local function B() context only:
>> B(10)
Index exceeds matrix dimensions.
Error in B (line 12)
callerFileName = stDebug(2).file;
My problem : I need a way to programmatically get the complete literal calling text, within function B(), no matter whether the caller is another M-file or the command-line.
I thought of looking in the MATLAB diary file, but apparently it's not guaranteed the last line of the diary text file will reflect the currently-executing command-line command at any given point in the executing call stack..
Any suggestions greatly appreciated!
Thanks, Brad
  댓글 수: 1
Matthew
Matthew 2017년 12월 15일
This isn't an answer to the question as it won't work for command line calls, but its worth noting that there are ways to get a calling line without scanning the file the calling line is in.
A pretty simple way is to create an error, and then use the getReport function on the MatlabException object.
try
error('DummyError');
catch ME
callStackDetails = getReport(ME);
end
callLine = regexp(callStackDetails,'(?<=Error in [^\n]*\n)[^\n]*','match','once');
callLine = strtrim(callLine);

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채택된 답변

Bradley Stiritz
Bradley Stiritz 2011년 9월 29일
I was able to find a solution, with help from Google, by searching for : matlab "command history". After all that tedious debate above, it's nice to see a four-line solution, which I've verified with limited testing. Note that it relies completely on undocumented MATLAB functionality.
Sincere thanks to StackOverflow.com for this solution. Hope it can help s/o else as well..
function str = getLastMATLABcommandLineStr()
% Function returns a string containing the last command entered in the Matlab Command Window..
% Code via : http://stackoverflow.com/questions/5053692/how-do-i-search-through-matlab-command-history
% Get session history from Java object:
history = ...
com.mathworks.mlservices.MLCommandHistoryServices.getSessionHistory;
% Convert to a vector of char strings:
historyText = char(history);
% Convert to a cell vector of strings:
cvHistory = cellstr(historyText);
% Extract last string:
str = cvHistory{end};
end

추가 답변(2개)

Jan
Jan 2011년 9월 25일
Sorry for this not being an direct answer:
There are very likely cleaner methods than parsing the contents of the calling line. The input can be a function, which has side-effects such that a textual pasing will not be successful. This method will fail if called from a Mex function or a P-coded fail also.
Reading the program text of the caller is another variant of the old EVAL problems. Therefore I strongly recommend to find a more direct solution, which si safer, cleaner and is less prone to errors.
  댓글 수: 7
Jan
Jan 2011년 9월 29일
@Brad: "Can you think of any software which asks the user to enter the same information twice, but does not validate the entries against each other?" Yes, Windows UAC. And I agree that it is a good idea not to compete with it.
And I agree, that my answer does *not* solve your problem.

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Daniel Shub
Daniel Shub 2011년 9월 25일
I think you always want the last function on the stack:
callerFileName = stDebug(end).file;
callerLineNumber = stDebug(end).line;
  댓글 수: 2
Bradley Stiritz
Bradley Stiritz 2011년 9월 25일
Just to clarify, here's the call-stack output we wish to generate when B() is called from the command-line:
>>B(10)
Complete text of calling code is : 'B(10)'

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