[binarybanana]

Common Lisp does have a "proper strong type system". What it doesn't have OOTB is is static type checking at compile time. Those two are orthogonal issues. Although with CLOS (object system) you get pretty close. Some compilers like sbcl have type inference and you can declare types of variables and function arguments. There are also libraries that take this much further to make it work more like a statically typed language. There are even libraries that add things like dependent types and such crazy things.

Note that static type checking can be difficult to work with when using the prominent interactive programming style since the types aren't always wellhdefined and/or in flux while writing and adding new bits and pieces of code, or redefining types, adding struct/object members at runtime, etc.

But it's possible, yes.

[lisper]

And it is certainly possible to put static type inference into a DSL embedded within Lisp.