Re: [Nano-devel] disable a time-consuming multiline regex?

[Mike Frysinger]

On 01 Dec 2015 21:14, Benno Schulenberg wrote:
> The following regex in c.nanorc is very time-hungry:
> 
>   # Multiline strings.  This regex is VERY resource intensive!
>   color brightyellow start=""(\\.|[^"])*\\[[:space:]]*$" end="^(\\.|[^"])*""
> 
> For example, run 'src/nano --cons +4444 src/winio.c',
> then press and hold ^Y.  See how the flying by of the
> pages is fairly smooth.
> 
> Then exit nano and run the same command again, and
> type ^Y ^K.  Then press and hold ^Y.  See how after
> a few seconds the scrolling begins to stutter and
> pause (at least here it does, on a 1.6 GHz Atom).
> 
> Maybe that string should be commented out by default?
> (When I do so, scrolling becomes fluid.)
> 
> Also, the regex doesn't work fully correctly.
> For example, run 'src/nano imperfect.c' and type:
> 
> "one
> two
> three"
> 
> The string isn't coloured, which is correct, because backslashes
> are missing.  Now type a backslah after "one" -- all three words
> are coloured.  But that should happen only when there is also a
> backslash after "two".  Nano's regexes are not capable of expressing
> this, so maybe also therefore such an imperfect matcher should be
> disabled?

i tend to disable it as well because it gets other cases wrong like:
#define FOO() \
    printf("ok!"); \
    blah; \
    printf("done!");

it causes the whole body of the macro to be highlighted
-mike

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