[macintux]

My primary language (Erlang) does. I assume all functional programming languages do.

[safek]

That's true. I suppose my next argument is that seeing matrix.append(row) on its own line signals strongly that this is not a functional language.

[thedufer]

Is that true? I thought most functional programming languages did call-by-reference. I mean, if you have immutable data you can't tell the difference (outside of performance).

[macintux]

Under the hood it's probably by reference, but the semantics are by value. By reference indicates that the original value can be changed in the called function.

I think. Not a language lawyer.