Error formatting macro: pagetree: java.lang.NullPointerException
Skip to end of metadata
Go to start of metadata
You are viewing an old version of this page. View the current version. Compare with Current  |   View Page History

Problem

Bit operations don't have the same semantics that the rest of Clojure's numeric functions do. Primitive semantics should be the default, there should be no conditionals, and bit ops should map directly to primitive ops.

Steps

  1. Bit ops have primitive semantics by default (CLJ-772 bit ops to have primitive semantics by default, no conditionals, direct mapping to JVM primitive ops)
  2. Bit ops with boxed semantics are in another ns (CLJ-767 Remove support for non-primitive bit-shift operations)
  3. n-ary bit ops are inlined (CLJ-184 n-ary bit functions, also inlining of n-ary bit and math operations)

Questions

  1. Does "boxed semantics" mean negative shift distance flips the direction?  Does it mean anything else, e.g., returning BigInt on overflow?  Can this just be left to the API on BigInteger?
  2. Changing bit ops Numbers methods to map directly to primitive ops means a breaking change with respect to negative bit-shift distances.  Is this intended/acceptable?
  3. Assuming no overflow support, is there any reason bit ops should not all return long, as opposed to sometimes Object?
    1. If no, do we still need the BitOps interface?
    2. Can the bit ops fns be written using prim interfaces?
  4. Support of n-ary ops via reduce causes a multiple orders of magnitude performance hit. Is unbounded expansion an acceptable solution for inline n-ary support?  Is there work underway for better support for reduce when working with primitive-taking/returning fns?

Related Tickets

Labels: