What is Gradual Typing

Re:What is Gradual Typing by rurban on Wednesday November 12, 2014 @06:50AM (#8594998)

Optional type annotations do exist for ages in Common Lisp, and the optimizations are implementation specific. All good implementations do not only check the types, they are mostly used to optimize the data types (raw vs boxed) and reduce unneeded run-time type checks and unneeded generic methods. See e.g. the python compiler for SBCL, formerly knows as CMUCL.

Perl5 also has optional types since 15 years, just the implementations (checkers and optimizers) were broken in the last big refactoring around 5.10, and there's no interest in enabling it again. The optimizing perl5 compiler B::CC honors optional types (besides doing type inference for core types, IV, NV and PV) and gets a typical 2-5x speedup. http://act.yapc.eu/ye2013/talk/4637

BTW: This is a very old article, and was posted here some months ago already.

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Re:What is Gradual Typing by masklinn on Wednesday November 12, 2014 @07:38AM (#8595142)

Erlang has also had a gradual type system (and a fairly interesting one at that[0]) for a long time: http://learnyousomeerlang.com/dialyzer

AFAIK there's no optimisation based on that, just typechecking.

[0] it's interesting in that where most typecheckers restrict language semantics as they require a form of correctness proof, dialyzer is optimistic and only errors out if types are clearly inconsistent

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