I tried the example from the std.regex documentation:

//Comify a number auto
com = regex(r"(?<=\d)(?=(\d\d\d)+\b)","g");
assert(replace("12000 + 42100 = 54100", com, ",") == "12,000 + 42,100 = 54,100");

It did not work for me when I entered numbers with more than 6 digits. Using \d{3} instead of \d\d\d worked in all cases. The issue appears to be in the lookahead, not the lookbehind. Here are some examples:


import std.regex, std.stdio;

int main(string[] args)
{
  if( args.length != 2 ) {
    writefln("usage: rdmd commas.d  digits", args[0]);
    return 1;
  }
  auto digits = args[1];

  // \d{3} ok, with and without lookbehind
  auto rx_bf_d3 = regex( r"(?<=\d)(?=(\d{3})+\b)", "g");
  writefln( "rx_bf_d3 : %s", replace(digits, rx_bf_d3, ",") );
  auto rx_f_d3 =   regex( r"(\d)(?=(\d{3})+\b)", "g");
  writefln( "rx_f_d3  : %s", replace(digits, rx_f_d3, "$1,") );

  // \d\d\d fails, with and without lookbehind
  auto rx_bf_ddd = regex( r"(?<=\d)(?=(\d\d\d)+\b)", "g");
  writefln( "rx_bf_ddd:  %s ", replace(digits, rx_bf_ddd, ",") );
  auto rx_f_ddd =  regex( r"(\d)(?=(\d\d\d)+\b)", "g");
  writefln( "rx_f_ddd :  %s", replace(digits, rx_f_ddd, "$1,") );
  return 0;

}

/*
$> rdmd commas.d 1234567
rx_bf_d3 : 1,234,567
rx_f_d3  : 1,234,567
rx_bf_ddd:  1234,567
rx_f_ddd :  1234,567
*/

Am I missing something, or is this a bug?

Thanks,

Peter

12/26/2012 9:26 PM, Peter Summerland пишет:
> I tried the example from the std.regex documentation:
>
> //Comify a number auto
> com = regex(r"(?<=\d)(?=(\d\d\d)+\b)","g");
> assert(replace("12000 + 42100 = 54100", com, ",") == "12,000 + 42,100 =
> 54,100");
>
> It did not work for me when I entered numbers with more than 6 digits.
> Using \d{3} instead of \d\d\d worked in all cases. The issue appears to
> be in the lookahead, not the lookbehind.
[snip]

>
> Am I missing something, or is this a bug?
>

It is and is something new (or a regression). Please go ahead and file it:

http://d.puremagic.com/issues/

Meanwhile I'll try to fix this before we get 2.061 out the door.

-- 
Dmitry Olshansky

On Wednesday, 26 December 2012 at 21:16:30 UTC, Dmitry Olshansky wrote:
> 12/26/2012 9:26 PM, Peter Summerland пишет:
>> I tried the example from the std.regex documentation:
>>
>> //Comify a number auto
>> com = regex(r"(?<=\d)(?=(\d\d\d)+\b)","g");
>> assert(replace("12000 + 42100 = 54100", com, ",") == "12,000 + 42,100 =
>> 54,100");
>>
>> It did not work for me when I entered numbers with more than 6 digits.
>> Using \d{3} instead of \d\d\d worked in all cases. The issue appears to
>> be in the lookahead, not the lookbehind.
> [snip]
>
>>
>> Am I missing something, or is this a bug?
>>
>
> It is and is something new (or a regression). Please go ahead and file it:

Done

>
> http://d.puremagic.com/issues/
>
> Meanwhile I'll try to fix this before we get 2.061 out the door.

Thanks for the great regex library!