>It started out as a pure Scheme, then "took a practical turn" as the parent said.
False.
PLT Scheme, like all serious schemes, started out as Scheme extended for practical use.
Racket, what PLT Scheme became, isn't an extended Scheme: it is a different language with its own semantics. That's not good, bad, or pedantic, but it is true.
>You can still make it act like a pure Scheme with a #lang directive.
No, you can make it use RnRS. The difference is that in actual Schemes, the language you write in is extended RnRS, not an entirely different language.
At the end of the day, calling Racket a Scheme is like calling Java a C: they look similar, but they are radically different under the surface.
I think the truth is somewhere between what you and dTal said. First, Racket isn't much more different from "Scheme" now than when we changed the name in 2010. Second, if you copy-and-paste a random portable Scheme program into #lang racket, it will probably work. This is somewhat less likely than with most systems that call themselves Scheme, but way more likely than with Scheme's closest relatives (Arc, Clojure, etc), and similarly with Java vs C.
Ultimately, Scheme is a language family, and Racket is further away than most or all of the other members, but there's considerable distance between Guile and Gambit as well (to pick some other examples).
Full disclosure: I'm a core developer of Racket, but not all of us have the same perspective on this question.
Not at all.
>It started out as a pure Scheme, then "took a practical turn" as the parent said.
False.
PLT Scheme, like all serious schemes, started out as Scheme extended for practical use.
Racket, what PLT Scheme became, isn't an extended Scheme: it is a different language with its own semantics. That's not good, bad, or pedantic, but it is true.
>You can still make it act like a pure Scheme with a #lang directive.
No, you can make it use RnRS. The difference is that in actual Schemes, the language you write in is extended RnRS, not an entirely different language.
At the end of the day, calling Racket a Scheme is like calling Java a C: they look similar, but they are radically different under the surface.