• HaraldZealot (6/6) Jan 05 2015 For my particular project (it binds with something like finite
• Jakob Ovrum (8/14) Jan 06 2015 For UTF, there's already std.utf.strideBack which does most of
• Jonathan M Davis via Digitalmars-d (6/17) Jan 06 2015 I'm pretty sure that you basically have to do what strideBack does befor...
• HaraldZealot (3/11) Jan 06 2015 I have to read more attentively std.utf, but strideBack seems
• Andrei Alexandrescu (2/8) Jan 06 2015 back() and popBack() for narrow strings do reverse decode. -- Andrei
• HaraldZealot (9/23) Jan 06 2015 I need reverse decode from any position, not only from the last.

"HaraldZealot" <harald_zealot tut.by> writes:

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?

"Jakob Ovrum" <jakobovrum gmail.com> writes:

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.

Jonathan M Davis via Digitalmars-d <digitalmars-d puremagic.com> writes:

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

"HaraldZealot" <harald_zealot tut.by> writes:

 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!!!

Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:

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

"HaraldZealot" <harald_zealot tut.by> writes:

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.