bug#22983: syntax-ppss returns wrong result.

[Alan Mackenzie]

Hello, Dmitry.

On Sat, Sep 09, 2017 at 15:18:11 +0300, Dmitry Gutov wrote:
> On 9/9/17 1:20 PM, Alan Mackenzie wrote:

> > In the implementation, I have left the function `syntax-ppss' untouched
> > except for adding a function call to set up the cache right at the
> > start.  I have refactored syntax-ppss-flush-cache, extracting a function
> > which is called directly from the cache-selecting code.  Other than
> > that, there is one new function (which switches the current cache in
> > use) and a few new variables to keep track of the caches.

> Not sure I understand. If you call (syntax-ppss) with significantly 
> different narrowings without flushing the cache (e.g. without modifying 
> the buffer), sounds like it'll have to return the same results under the 
> described implementation.

> If so, it doesn't sound strict enough.

On changing from one narrowing to another narrowing (more precisely, when
point-min is changed, neither value being 1), the cache is flushed, even
though the buffer has not been modified.

Anyhow, I've posted a patch elsewhere on this thread.  Comments on it
would be welcome.

[ .... ]

-- 
Alan Mackenzie (Nuremberg, Germany).