Thanks! First-time user feedback is incredibly valuable, and hard to come by.

> After reading through it, I discovered that I was supposed to use - to select an argument and = to enter a value for it.

You can also double-click the right part of an operation. I agree, though, on-boarding is one of my weaknesses right now.

> I haven't purchased too many Mac Store apps, maybe this is some limitation of that, but I've never had an app before that couldn't access a file without my first telling it where it was allowed to look. Is that really necessary?

I'm having a little trouble unpacking the triple-negative here, but basically, yes. The Mac App Store requires sandboxing, and the sandbox prevents the app from accessing a file until the user shows some intent to access it -- like by drag-n-drop, or a system Open File panel.

There are some exceptions, like public files in /System, or if an app has the "com.apple.security.assets.music.read-only" entitlement then it can read your ~/Music folder. In the general case, though, an app can only access files once it's been given explicit permission.

(Oh, and in case you didn't try this: you can drag-n-drop a file onto the Strukt icon in the dock, or into an existing pipeline window, and it'll add the appropriate "Load File" operation, and also automatically add that to the list of authorized files. I do try to save you a step, where I can.)

> I have an outstanding question on how to insert one between two steps, but I haven't needed to do it yet so I haven't experimented.

You can use control-O (like Emacs -- or Mac text fields) for this. It's also in the Edit menu, though one thing I've learned recently is that nobody looks in the Edit menu, so I'm working on some alternative methods that are more discoverable.

> TSV was able to break it up into two fields, but I don't have any control over specifying the keys for the fields, it just automatically eats the first row of data and uses it as the key name. :(

Good point. CSV/TSV don't actually mandate that the first line contains headers (even though it often is), so those operations should let you bypass that functionality.

One hacky workaround, for now (which I admit there's no way you would have guessed): you can use "Literal Value" with string="foo<tab>bar" where="before" to prepend a line to your data, before the Parse TSV operation.

> I then tried to add a Parse JSON operator. First tried to point it at the "key" field, got nothing back, so I tried the "value" field. Still nothing.

Hmm, it looks like my JSON parser is expecting an object at the top-level, and doesn't seem to work with an array, or anything else. It should really be more lenient.

I do want to have native JSON support (not just strings, or atoms) someday. If you have a sample file you can share with the structure you've got, I can make sure it works well. I'm not familiar with Kafka but "JSON-in-TSV" sounds like exactly the sort of thing I should support.

> Sorry that this is kinda a negative review. Don't let it get you down, there is a lot of promise in the concept and interface.

I don't take it as negative at all. You took a chance on a new app, and even when it failed for you, you took the time to write down exactly what I need to do to make it better! I wish everybody did that. This is my favorite comment so far, because it's loaded with actionable feedback.