Package net.hydromatic.morel.eval

Class Applicable2<R,​A0,​A1>

  • Type Parameters:
    R - return type
    A0 - type of argument 0
    A1 - type of argument 1
    All Implemented Interfaces:
    Applicable, Describable
    Direct Known Subclasses:
    Codes.ListNth, Codes.ListTake, Codes.RealCompare, Codes.StringSub
    public abstract class Applicable2<R,​A0,​A1>
extends ApplicableImpl
    Applicable whose argument is a 3-tuple.

    Implementations that use Applicable3 are more efficient and concise than ApplicableImpl because there is no need to create an ephemeral tuple (Java List) to pass the arguments, and Java's generics provide the casting.

    But the rewrite assumes that the function is strict (always evaluates all arguments, even if the function throws) and doesn't use EvalEnv, so it is not appropriate for all functions. For example, andalso evaluates its arguments lazily and therefore cannot be an Applicable2.

    If a function has an Applicable2 implementation and the argument tuple is evaluated whole, the old evaluation path will be used. For example, the first call below uses apply and the second uses apply: 

    
 - Math.pow (2.0, 3.0);
 val it = 8.0 : real
 - Sys.plan ();
 val it = "apply2(fnValue Math.pow, constant(2.0), constant(3.0))" : string
 - Math.pow (List.hd [(2.0, 3.0)]);
 val it = 8.0 : real
 - Sys.plan ();
 val it =
   "apply(fnValue Math.pow, argCode apply(fnValue List.hd, argCode tuple(tuple(constant(2.0), constant(3.0)))))"
   : string
    See Also:
    Applicable3

    • Constructor Detail

      • Applicable2

        protected Applicable2​(BuiltIn builtIn,
                      Pos pos)

      • Applicable2

        protected Applicable2​(BuiltIn builtIn)