Matlab中多行注释的正则表达式

Question

I try to write a regexp that would match this pattern:

%{
...
...
%}

It should also match:

sth   %{
...
...
  %}

or

%{
something%}
%}again something
%}

but not:

%{something
...
%}

or

%{
...
%}something

or

%{
...
something%}

So it matches everything between a line with whatever character followed by %{ and a line with only %} (see multiline comment Matlab : https://fr.mathworks.com/help/matlab/matlab_prog/comments.html )

I tried this :

     ^.*%\{\n(^((?!%\}).)*\n)*(\s)*%\}\n

It works well to find the block, but for example, it doesn't match:

%{
%}something
...
%}

Do you have any ideas ?

Answer 1

You may use

^.*%\{(?:\n(?!.*%\{).*)*\n\s*%\}$

See the regex demo . Use it with a multiline modifier.

If your regex engine is Java, you may use \\R to match any line break and \\h instead of \\s to match any horizontal whitespace:

^.*%\{(?:\R(?!.*%\{).*)*\R\h*%\}$

See this regex demo .

Details

• ^ - start of a line
• .* - any 0+ chars other than line break chars as many as possible
• %\\{ - a %{ substring
• (?:\\n(?!.*%\\{).*)* - 0 or more sequences of
  • \\n(?!.*%\\{) - a newline not followed with %{ anywhere on the current line
  • .* - any 0+ chars other than line break chars as many as possible
• \\n - a newline
• \\s* - 0+ whitespaces
• %\\} - a %} substring
• $ - end of line.