Re: prefix increment operator does not work as expected

[arnold]

Hello.

Thank you for taking the time to send in a report.

Hyunho Cho<mug896@naver.com> wrote:
>
> GNU Awk 5.0.1, API: 2.0 (GNU MPFR 4.0.2, GNU MP 6.2.0)
>  Operating System: Ubuntu 20.04 LTS
>  Kernel: Linux 5.4.0-39-generic
>  Architecture: x86-64
>
> ### 1. "++" prefix increment operator does not work as expected
>
> $ LC_ALL=C awk 'BEGIN { n = 12; x = 2; print n x++ }'  # OK
> 122
>
> $ LC_ALL=C awk 'BEGIN { n = 12; x = 2; print n ++x }'  # not as expected
> 122

Spaces in awk are tricky.  Concatenation is specified by placing two
expressions adjacent to each other, space is not explicitly an operator.

Furthermore, space is ignored between operators and operands:

        $ gawk 'BEGIN { x = 12 ; print x ++ ; print x }'
        12
        13

In the case of your example gawk is parsing the code as

        BEGIN { n = 12; x = 2; print (n ++) x }

This explains what's happening in all your other examples
as well.

To get what you wanted, use parentheses or stick a null string
in the middle:

        $ gawk 'BEGIN { n = 12; x = 2; print (n) ++x }'
        123
        $ gawk 'BEGIN { n = 12; x = 2; print n "" ++x }'
        123

Thanks,

Arnold