Apple Array System

Compiler-As-a-Library

Rather than an environment-based interpreter or a compiler invoked on the command line and generating object files, Apple generates machine code which can be used by a JIT compiler or in general.

Thus the same implementation can be used interpreted, compiled, or called from another language.

Documentation from Types

Like Haskell's Haddock or Doxygen, one can generate hyperlinked type signatures, e.g.

hypergeometric : Arr (i `Cons` Nil) float -> Arr (j `Cons` Nil) float -> float -> float

This saves the author from writing redundant documentation.

Programmatic type inference can be of aid in debugging.

Dimension As a Functor

This is based on J (and APL?). Looping is replaced by functoriality (map); we have a family of functors ('n)

Linear Memory Allocation

Rather than calling malloc to create a new array, arrays

<!-- reuse analysis --> <!-- no gc etc., comes from array &c. -->

Special Combinations

Apple takes inspiration from J's special combinations.

Moving Code vs. Moving Data

> For a computation to take place the data and the program have to be at the > same point in space-time - this is just physics. You can move the data to the > program or the program to the data, or both somewhere else. ... > data movement predominates.

• Joe Armstrong

Property Testing

Types act as witnesses, as in QuickCheck.