On: One in five genetics papers contains errors thanks...

[shagie]

     ~ % dc -v
     dc 6.5.0
     Copyright (c) 2018-2023 Gavin D. Howard and contributors
     Report bugs at: https://git.gavinhoward.com/gavin/bc

     This is free software with ABSOLUTELY NO WARRANTY.
     ~ % dc   
     3 _ 2 ^ p
     9
     _3 2 ^ p
     9
     3 2 ^ _ p
     -9
     5 _ p
     -5
     _5 p
     -5
     (control-D)

The version that I have appears to have _ parsed as an operator in addition to the negation of a numeric constant.

[gavinhoward → shagie]

I am the author of that dc.

You are correct about its behavior.

See https://git.gavinhoward.com/gavin/bc/src/branch/master/manua... (scroll down to the underscore command).

[bikenaga → shagie]

I'm using the version from Debian testing:

    dc -V
    dc (GNU bc 1.07.1) 1.4.1

In fact, in my version "-v" as opposed to "-V" isn't recognized as a valid option.

    3 _ 2 ^ p
    0

[gavinhoward → bikenaga]

I am Gavin Howard, the author of the other dc.

My dc does have a few differences from the GNU dc. I added the extension of using _ as a negative sign.

That is why you are both seeing behavior differences.