Hi Thomas, Thanks for your reply. I will open an issue, but I wanted to make sure I wasn’t overlooking an already available solution for my problem. Also, I thought it might be better to find consensus in the email list first. Or would it be better to have a discussion like this in an issue? I am not so familiar with the do’s and don’ts of open-source collaboration.
exch / swap Your suggestion is a third way to solve my problem. That would work fine. LIFO / FIFO Switching from LIFI to FIFO seems an easier solution to me. But I have no experience with stacks in programming languages, so maybe FIFO is too unconventional? Or would the change in behaviour from LIFI to FIFO be problematic for other users? I have never seen a PROJ pipeline using more than one value on the stack. Alternative A difference between PROJ and the language Forth is that PROJ has a coordinate value next to the stack. My suggested flip operator does the same as your exch / swap operator. The only difference is that I interpret the current coordinate value as the top value of the stack. The advantage is that my alternative needs just one step: +step +proj=flip +v_3 to do the same are your 3 steps: step omit_fwd proj=push v_3 # restore the geometrical height step omit_fwd proj=exch # swap the two heights, to get the geometrical to the top-of-stack step omit_fwd proj=pop v_3 # save the geophysical height Name Even if my alternative behaviour of flip would be implemented, I think your suggested name exch or swap would better explain what it does. Could there be a need for other stack operators too, like dup, over, rot and drop? To avoid confusion with other PROJ operators like axisswap and over, maybe a name like stackswap could be preferable? Jochem Disclaimer: De inhoud van deze e-mail is vertrouwelijk en uitsluitend bestemd voor de geadresseerde(n). Gebruik, openbaarmaking, vermenigvuldiging, verspreiding en/of verstrekking van deze informatie aan derden is niet toegestaan. Op al onze producten en diensten zijn onze algemene leveringsvoorwaarden van toepassing [https://www.kadaster.nl/algemene-leveringsvoorwaarden]. Disclaimer: This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you are not the intended recipient, you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. Our general terms and conditions of delivery apply to all our products and services [https://www.kadaster.com/general-terms-and-conditions].
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