Hi darisler,
Trying to write some code that reads in a list of coordinates, must have an odd number for some odd reason... but I'd like to know how to define '$coords' recursively

Do you have to define '$coords' recursively or repeatedly? And I don't know why you are using your regex like you are doing. If I get what you wanted, you can simply use split to get all the coords into an array, so they are in right order as follow in your original string, then loop for this like so: 

use v5.16;
use strict;

my $prBoundaryString = <<endPrBoundary;
'( (0.01 0.02) (0.0 1328.23) (0.01 0.02) (0.04 0.53) (0.03 44.23)
   (0.0 1328.23) (0.04 0.53)
 )
endPrBoundary

say "prBoundaryString=$prBoundaryString";

my @pts = grep { /\d+/ } split /\s+|[()]/, $prBoundaryString;

my $count = 0;
for ( 0 .. $#pts ) {
    if   ( $_ % 2 == 0 ) { print qq[-x$count=$pts[$_]] }
    else                 { print qq[-y$count=$pts[$_]]; $count++ }
}

[download]
Output: 
prBoundaryString='( (0.01 0.02) (0.0 1328.23) (0.01 0.02) (0.04 0.53) 
+(0.03 44.23)
   (0.0 1328.23) (0.04 0.53)
 )

-x0=0.01
-y0=0.02
-x1=0.0
-y1=1328.23
-x2=0.01
-y2=0.02
-x3=0.04
-y3=0.53
-x4=0.03
-y4=44.23
-x5=0.0
-y5=1328.23
-x6=0.04
-y6=0.53

[download]
Note: I modified the string you gave to show that it would get it in right order.
Hope this helps

If you tell me, I'll forget.
If you show me, I'll remember.
if you involve me, I'll understand.
--- Author unknown to me

In reply to Re: qr for recursive regex? by 2teez
in thread qr for recursive regex? by darisler

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