regular expression to replace ~ in code
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Edit: wrote new function StripTildes.m (see below) that works with all cases including output list on multiple lines
Edit: Modified the StripTildes function to use Daniel's regular expression from FEX function. This still does not work with modified TestFunction that uses a line continuation in the output argument list.
My version of Matlab does not support the use of ~ in an output argument list so it is giving syntax errors when I try to use some downloaded code.
My regular expressions are extremely rusty so I would appreciate a regular expression to use with regexprep to replace the ~ in an output argument enclosed in brackets but not replace ~= and other uses of the symbol.
responding to Azzi's comment: I would like to replace ~ with a regular variable name like 'dummy' so it will not cause a syntax error. The rest of the code should then work OK so long as there is no collision with an existing variable name.
My idea is to write a Matlab function to scan the downloaded code file, replace the ~'s, and then write the output to another file.
My editor 'Editpad' allows regular expression search and replace so I can also use the regular expression with it but for definiteness please stick with regexprep and I will take it from there.
Question: I am no clear the allowable syntax. Are only spaces between output arguments allowed such as?
[~ ~ y3 ] = NewFunction(foo);
TIA.
I created a function to implement the filtering and a test function as follows:
1. the filtering function
function StripTildes(filename)
% replace tildes in output parameter lists with 'the_dummy'
% in Matlab file filename
% outputs new file named filename_notilde.m to same directory as original file
pattern='~(?=[^\]\[='']*\][\s(\.\.\.)]*=[^=])'; % regular expression to find tildes
fid = fopen(filename); % open for read only
assert( fid ~= -1);
% read all file into one long string (including line break chars) so regexprep can work across lines
filetext = [];
while 1
tline = fgets(fid);
if ~ischar(tline), break, end % quit at end of file
filetext = [filetext tline];
end
fclose(fid);
filetext = regexprep(filetext,pattern,'the_dummy');
% output the file
[path,name,ext] = fileparts(filename);
out_name = [path filesep name '_notilde' ext];
fidout = fopen(out_name,'w');
assert( fid ~= -1);
fwrite(fidout,filetext);
fclose(fidout);
2. the function to test
function TestFunction
if 1 ~= 0
[~,~,y] = LocalFunction;
elseif ~(true) or ~exist(foo,'dir')
[~ ~ y ] = LocalFunction;
end
tf = [~true, 1~=0, ...
];
[~,~, ...
y] = LocalFunction;
function [y1,y2,y3] = LocalFunction
y1 = 0;
y2 = 0;
y3 = 0
p.s. I cannot afford to upgrade my Matlab version so please do not suggest it as a solution
6 Kommentare
per isakson
am 11 Jul. 2013
Bearbeitet: per isakson
am 11 Jul. 2013
I modified the expression below to handle [~,~,y] and [~,a,~]
Akzeptierte Antwort
per isakson
am 11 Jul. 2013
Bearbeitet: per isakson
am 11 Jul. 2013
regexprep( '[ a, ~, b ]', '(?<=\[.+?,[ ]*)\~(?=.+?])', 'dummy' )
returns
[ a, dummy, b ]
Firstly, backup all your files
and make more tests
.
.
Bugfix:
str = '[~,~,y] = LocalFunction;';
regexprep( str, '(?<=\[(.+?,)|([ ]*)[ ]*)\~(?=.+?])', 'dummy' )
returns
ans =
[dummy,dummy,y] = LocalFunction;
.
and another bugfix
str = '[~,a,~] = LocalFunction;';
regexprep( str, '(?<=\[(.+?,)|([ ]*)[ ]*)\~(?=.*?])', 'dummy' )
returns
ans =
[dummy,a,dummy] = LocalFunction;
and more test needed
7 Kommentare
per isakson
am 11 Jul. 2013
Bearbeitet: per isakson
am 11 Jul. 2013
Try this
reg = '(?<=\[(.+?,)|([ ]*)[ ]*)\~(?=.*?][ ]*(=|(\.\.\.)))';
str = '[~,a,~] = LocalFunction;';
regexprep( str, reg, 'dummy' )
str = 'tf = [~true, 1~=0, ...';
regexprep( str, reg, 'dummy' )
str = '[~,a,~] ...';
regexprep( str, reg, 'dummy' )
The expression looks at one line. Thus, I give up on this one
[~,~, ...
y] = LocalFunction;
and after that we will face
[y,~, ...
~] = LocalFunction;
You could
- concatenate the continuation lines
- search&replace
- restore the continuation lines
per isakson
am 11 Jul. 2013
FileLocator Lite is a free really good find_in_files_program. It will help you find the remaining cases, which you should edit interactively.
Weitere Antworten (1)
Azzi Abdelmalek
am 11 Jul. 2013
Bearbeitet: Azzi Abdelmalek
am 11 Jul. 2013
str='one ~ two ~= three ~'
pattern='~(?!\S)'
regexprep(str,pattern,'dummy')
2 Kommentare
Daniel Shub
am 11 Jul. 2013
I think this will fail if the ~ is in a string. It is possibly better to also include [] since I think that is a requirement. I think counting opening/closing quoutes might be hard.
Azzi Abdelmalek
am 11 Jul. 2013
Bearbeitet: Azzi Abdelmalek
am 11 Jul. 2013
str=' z~d one ~ two ~= three ~'
pattern='~(?!\=)'
regexprep(str,pattern,'dummy')
%or
str=strrep(str,'~=','obma')
str=strrep(str,'~','dummy')
str=strrep(str,'obma','~=')
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