[Animats]

I'm not saying those things should be written in a declarative form, just that what the author is calling "declarative" isn't.

If you wanted to do something like that in a declarative way, though, consider a spreadsheet with an intelligent evaluator. The spreadsheet is a declaration of a dependency relationship. When a number is changed, the numbers depending upon it change. It's not always just a recalculation, either. There are spreadsheets that let you work backwards (change a total, watch the inputs change), and cloud-based spreadsheets that sync (one of YCombinator's companies, Fivetran, has one).

Spreadsheets also suffer from imperative creep. People try to use Excel spreadsheets for iterative work, which gets away from the declarative design.

[kyllo]

Spreadsheets also suffer from imperative creep. People try to use Excel spreadsheets for iterative work, which gets away from the declarative design.

...which is how we ended up with VBA macros.

[Dewie]

> If you wanted to do something like that in a declarative way, though, consider a spreadsheet with an intelligent evaluator. The spreadsheet is a declaration of a dependency relationship. When a number is changed, the numbers depending upon it change.

Seems like you're talking about functional reactive programming (or reactive programming in general).