in John Backus' 1978 FP paper "Can Programming Be Liberated from the von Neumann Style" he says
To help assemble the overall result from single words [von Neumann ie. conventional mutation-based] languages provide some primitive combining forms in the statement world--the for, while,and if-then-else statements--but the split between the two worlds [ie. between the expression-only and statement-only, as I understand him] prevents the combining forms in either world from attaining the full power they can achieve in an undivided world.
He shows the expressiveness of functional programming, that's what the paper is about, but he implies there's a similar expressiveness that can be got from the statements-only part, per the above quote. However I don't know what he means by this; he gives no examples.
The only language that appears ruthlessly statement-y that I can think of is (pure) prolog (eg. see https://en.wikipedia.org/wiki/Prolog#Quicksort, there's no expressions as such only statements giving relationships) and it's not statements so much as the backtracking that gives it the power.
So what did Backus mean by this? What example languages are there that are statement only (but without backtracking)?
Edit: belated link to orginal paper https://dl.acm.org/doi/10.1145/359576.359579 for interest.
(The question has nothing to do with BNF form. Also, if someone can edit the title to better summarise the long quote, please do Edit: that's much better, thanks!)