C and C++ are about the worst possible languages to use for scripting—let alone interactive interfaces, which even the current crop of conventionally “scripting” languages is kind of bad at[1].
Having an interpreter to poke at in-development code, though, would IMO still be useful. (I wouldn’t use Haskell or SML/OCaml for scripting either, and yet I swear by their interpreters.) Even GDB has something like one—the expression fragment the “print” command understands includes casts, which means it can parse type names, and for unoptimized C that’s honestly half the battle.
Or take it from (younger) Russ Cox[2]:
> All current C environments suffer from a much larger problem, namely a lack of interactivity. You can’t sit at a prompt, enter C fragments, and see what happens.
[1] http://yosefk.com/blog/i-cant-believe-im-praising-tcl.html