Package hydra.lib.lists

Class SafeHead

java.lang.Object

hydra.tools.PrimitiveFunction

hydra.lib.lists.SafeHead

public class SafeHead
extends PrimitiveFunction

Safely returns the first element.

Constructor Summary

Constructors

Constructor	Description
SafeHead()

Method Summary

Modifier and Type	Method	Description
static <X> Maybe<X>	apply(List<X> list)	Apply the function to it single argument.
protected Function<List<Term>,Flow<Graph,Term>>	implementation()	A dynamic/interpreted implementation of the function.
Name	name()	The unique name of the primitive function.
TypeScheme	type()	The datatype of the primitive function.

Methods inherited from class hydra.tools.PrimitiveFunction

term, toNative

Methods inherited from class java.lang.Object

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

Constructor Details

SafeHead

public SafeHead()

Method Details

name

public Name name()

Description copied from class: PrimitiveFunction

The unique name of the primitive function.

Specified by:

name in class PrimitiveFunction

Returns:

the name of this primitive function

type

public TypeScheme type()

Description copied from class: PrimitiveFunction

The datatype of the primitive function.

Specified by:

type in class PrimitiveFunction

Returns:

the type scheme of this primitive function

implementation

protected Function<List<Term>,Flow<Graph,Term>> implementation()

Description copied from class: PrimitiveFunction

A dynamic/interpreted implementation of the function.

Specified by:

implementation in class PrimitiveFunction

Returns:

the function implementation

apply

public static <X> Maybe<X> apply(List<X> list)

Apply the function to it single argument.

Type Parameters:

X - the element type

Parameters:

list - the list to get the head from

Returns:

an optional containing the first element, or empty if the list is empty