water.rapids.ast

Class AstBuiltin<T extends AstBuiltin<T>>

java.lang.Object

water.Iced<T>

water.rapids.ast.AstRoot<T>

water.rapids.ast.AstPrimitive<T>

water.rapids.ast.AstBuiltin<T>

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, java.lang.Cloneable, Freezable<T>

Direct Known Subclasses:

AstDistance, AstGrep, AstIsNa, AstMoment, AstPivot, AstUniOp, AstWhichFunc

public abstract class AstBuiltin<T extends AstBuiltin<T>>
extends AstPrimitive<T>

(Replacement for AstPrimitive).

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
AstBuiltin()

Method Summary

Methods

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.
protected Val	exec(Val[] args) Most Ast* functions will want to override this method.

Methods inherited from class water.rapids.ast.AstPrimitive

args, description, example, exec, nargs

Methods inherited from class water.rapids.ast.AstRoot

str, toString

Methods inherited from class water.Iced

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

Methods inherited from class java.lang.Object

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

Constructor Detail

AstBuiltin

public AstBuiltin()

Method Detail

apply

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

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

The default implementation of this method executes all Asts within the provided environment, and then calls exec(Val[]) passing it the arguments as the list of Vals. A derived class will then only need to override the second `exec()` function which is much simpler.

However for certain functions (such as short-circuit boolean operators) executing all arguments is not desirable -- these functions would have to override this more general method.

Specified by:

apply in class AstPrimitive<T extends AstBuiltin<T>>

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.

exec

protected Val exec(Val[] args)

Most Ast* functions will want to override this method. The semantics is "call this function with the provided list of arguments".