Re: decodeReverse

[HaraldZealot via Digitalmars-d]

On Tuesday, 6 January 2015 at 16:58:24 UTC, Andrei Alexandrescu 
wrote:

On 1/5/15 10:43 PM, HaraldZealot wrote:
For my particular project (it binds with something like finite 
state
machine) I will write some counterpart of decode function from 
std.utf.
Future function will decode string backward, return dchar and 
change

index passed by reference.

Is it interesting for community that I code this feature in 
general way

targeting in phobos for future?


back() and popBack() for narrow strings do reverse decode. -- 
Andrei


I need reverse decode from any position, not only from the last.
I have coded a litle with stideBack allready, it works. But usage 
isn't clear as could: first strideBack, then decode, and decode 
move index forward, then I have to strideBack again :)


Perhaps i will wrap such algorithm in some function, but an other 
side i will be forced to optimize that and write real decodeBack 
function.

Re: decodeReverse

[Andrei Alexandrescu via Digitalmars-d]

On 1/5/15 10:43 PM, HaraldZealot wrote:

For my particular project (it binds with something like finite state
machine) I will write some counterpart of decode function from std.utf.
Future function will decode string backward, return dchar and change
index passed by reference.

Is it interesting for community that I code this feature in general way
targeting in phobos for future?


back() and popBack() for narrow strings do reverse decode. -- Andrei

Re: decodeReverse

[HaraldZealot via Digitalmars-d]

I'm pretty sure that you basically have to do what strideBack 
does before
you can decode a code point, so all decodeBack would do would 
be to do
exactly what back already does for strings, which is to use 
strideBack

followed by decode.

- Jonathan M Davis


I have to read more attentively std.utf, but strideBack seems 
very suitable for me.


Thanks you both!!!

Re: decodeReverse

[Jonathan M Davis via Digitalmars-d]

On Tuesday, January 06, 2015 08:09:57 Jakob Ovrum via Digitalmars-d wrote:
> On Tuesday, 6 January 2015 at 06:43:13 UTC, HaraldZealot wrote:
> > For my particular project (it binds with something like finite
> > state machine) I will write some counterpart of decode function
> > from std.utf. Future function will decode string backward,
> > return dchar and change index passed by reference.
> >
> > Is it interesting for community that I code this feature in
> > general way targeting in phobos for future?
>
> For UTF, there's already std.utf.strideBack which does most of
> the work. I don't know why there is no std.utf.decodeBack -
> should be very simple to wrap over strideBack.

I'm pretty sure that you basically have to do what strideBack does before
you can decode a code point, so all decodeBack would do would be to do
exactly what back already does for strings, which is to use strideBack
followed by decode.

- Jonathan M Davis

Re: decodeReverse

[Jakob Ovrum via Digitalmars-d]

On Tuesday, 6 January 2015 at 06:43:13 UTC, HaraldZealot wrote:
For my particular project (it binds with something like finite 
state machine) I will write some counterpart of decode function 
from std.utf. Future function will decode string backward, 
return dchar and change index passed by reference.


Is it interesting for community that I code this feature in 
general way targeting in phobos for future?


For UTF, there's already std.utf.strideBack which does most of 
the work. I don't know why there is no std.utf.decodeBack - 
should be very simple to wrap over strideBack.


However, for grapheme clusters, there isn't yet a counterpart for 
std.uni.graphemeStride/decodeGrapheme, which notably affects 
std.uni.byGrapheme, which is currently not a bidirectional range. 
Any improvement would be much appreciated.

decodeReverse

[HaraldZealot via Digitalmars-d]

For my particular project (it binds with something like finite 
state machine) I will write some counterpart of decode function 
from std.utf. Future function will decode string backward, return 
dchar and change index passed by reference.


Is it interesting for community that I code this feature in 
general way targeting in phobos for future?