[eru]

Not all control-flow primitives are necessary.

Eg Haskell and Scheme get by without 'while' and 'goto'.

Haskell would do just fine without a built-in 'if': you can define 'if' as a function via pattern matching.

Given that perspective, the article would be a call to use more expressive types than Booleans to match on---and in lots of cases not to match at all, but provide what would be the result of the match as an argument to the function.

[qwertyuiop924]

Scheme and Haskell have other primitives that take the place of while and goto.

But yes, using more expressive match types or parameters is a good idea. As for providing the result as an argument, that can be a good pattern, but isn't always practical. Note what I said in my original comment about using your own discretion.

[eru]

They don't have `other primitives': they have function calls. Most languages have function calls these days.

[qwertyuiop924]

Yes, I read LTUI and LTUD. But in most languages, function calls and loops don't have the same semantics. I'll call that a different loop primitive.

[eru]

For C, this seems to be implementation defined.

(At least for C as encountered in the wild, I don't know about C the standard.)

Most modern C compilers support tail call optimization.

I don't know about `most languages'. Eg I know Java on the JVM doesn't do tail call optimization. Lots of languages probably do not require TCO of their implementations, though.