Update: this is obsolete as a CurrentValue workaround
If your only need is to have nested loops and be able to reference outer
CurrentValue, you should do this now with aWithName()construct like hereHowever, the Iterator Tables pattern still holds up if you need to:
create logic more complex than a ForEach loop in the ForEach loop — like in the video below there’s a “Do… While” loop that doesn’t just go over a defined collection of items.
be able to monitor the execution of steps, catch and rerun failed steps — for that you could still use an iterator table like I did it here with the HLP Doc Distro Runner table — it is your model iterator table.
After answering the CurrentValue issue questions so. many. times, I finally recorded the tutorial on a Coda data processing pattern I use as a workaround for this very problem. It involves creating single-row helper tables that store outer CurrentValue values into cells, so that they’re accessible in nested Filters and FormulaMap loops. I call this pattern Iterator tables, and beside being a workaround for CurrentValue, these are very powerful for doing more complicated calculations
The video is ~40 minutes long. The first ~8 minutes explain the pattern using a simple example. The rest of the video discusses a much more advanced use. Also I noticed only now that my webcam window overlaps pieces of formulas 
sorry for that, see the sample doc below.
TL;DR:
- Create a single-row table with a button that first thing stores
CurrentValuein eachFormulaMapinto a separate column. Then reference that column when you want to retrieve that value.
Pros:
- Elegantly works around the
CurrentValuecontext issues. The table is like a collection of variables. - Avoids doc bloat because of buttons in each row — shrinks the doc tremendously if your table has lots of rows.
- You can build very complicated calculation logic there.
- You can break that logic down into steps, and examine for issues more easily, step by step.
Cons:
- Takes some effort to setup (but you know whom to hit up if you need some paid assistance
) - Most likely, you won’t be able to set up automation to run this for you. In one of my setups automations were failing with unspecified Coda error.
- Iterating over large datasets will generate hundreds or thousands of Coda “ops” (tiny edit operations), which are then sent very slowly (like, 4 per second) to Coda servers and synced to other collaborators. You’ll have to wait for the doc to save all changes before you can close the tab. You’ll know when it’s not finished yet — trying to close or reload the tab will show you a warning.
- Frugal free plan users: it adds 1 table and 1 row to your object and row count
Also, the sample doc:
Once again I remind you that I’m going to run a blog codatricks.com — please subscribe for tricks like this. I’m ashamed to say it’s been a year and I still haven’t started publishing anything there, and I’m putting everything out in this Community instead. For me, writing articles is much harder than just spinning unrehearsed single take videos like this one. But I’ll get there.
