water.rapids.ast.prims.reducers

Class AstReducerOp

java.lang.Object

water.Iced<T>

water.rapids.ast.AstRoot<T>

water.rapids.ast.AstPrimitive

water.rapids.ast.prims.reducers.AstReducerOp

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, java.lang.Cloneable, Freezable

Direct Known Subclasses:

AstRollupOp

public abstract class AstReducerOp
extends AstPrimitive

Subclasses take a Frame and produces a scalar. NAs -> NAs

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
AstReducerOp()

Method Summary

Modifier and Type	Method and Description
Val	apply(Env env, Env.StackHelp stk, AstRoot[] asts) Primary method to invoke this function, passing all the parameters as the `asts` list.
int	nargs() Number of function's arguments + 1.
abstract double	op(double l, double r) Override to express a basic math primitive

Methods inherited from class water.rapids.ast.AstPrimitive

args, description, example, exec

Methods inherited from class water.rapids.ast.AstRoot

str, toString

Methods inherited from class water.Iced

asBytes, clone, copyOver, frozenType, read, readExternal, readJSON, reloadFromBytes, toJsonBytes, toJsonString, write, writeExternal, writeJSON

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

AstReducerOp

public AstReducerOp()

Method Detail

nargs

public int nargs()

Description copied from class: AstPrimitive

Number of function's arguments + 1. Thus, a binary operator like '+' should be declared with 3 nargs: ["+", lhs, rhs]. For variable-argument functions this method should return -1.

Specified by:

nargs in class AstPrimitive

apply

public Val apply(Env env,
                 Env.StackHelp stk,
                 AstRoot[] asts)

Description copied from class: AstPrimitive

Primary method to invoke this function, passing all the parameters as the `asts` list.

Specified by:

apply in class AstPrimitive

Parameters:

env - Current execution environment. Variables are looked up here.

stk - TODO need clarification

asts - List of AstRoot expressions that are arguments to the function. First element in this list is the function itself.

Returns:

value resulting from calling the function with the provided list of arguments.

op

public abstract double op(double l,
                          double r)

Override to express a basic math primitive