Nilad (QDL root module 1.5.6 API)

java.lang.Object
- edu.uiuc.ncsa.qdl.expressions.ExpressionImpl
- - edu.uiuc.ncsa.qdl.expressions.Nilad

All Implemented Interfaces:

ExpressionNode, ExpressionInterface, HasResultInterface, Statement, Serializable
```
public class Nilad
extends ExpressionImpl
```
This would be an operator that takes no arguments. Niladic user defined functions (no arguments) abount. It is possible to have a niladic operator in QDL, but as of yet there is no example of one. One possible way would be to use these as control symbols, such a special operator that means to, say, open an editor window. These would also require special handling inthe parser.
Created by Jeff Gaynor
on 1/13/20 at 3:36 PM

See Also:

Serialized Form

Field Summary
- Fields inherited from class edu.uiuc.ncsa.qdl.expressions.ExpressionImpl
  arguments, result, valence
- Fields inherited from interface edu.uiuc.ncsa.qdl.statements.ExpressionInterface
  ALL_INDICES_NODE, ALT_IF_NODE, ASSIGNMENT_NODE, CLOSED_SLICE_NODE, COMPARISON_DYAD_NODE, CONSTANT_NODE, DYAD_NODE, DYADIC_FUNCTION_REFERENCE_NODE, EXPRESSION_STEM_NODE, EXPRESSION_STEM2_NODE, FUNCTION_REFERENCE_NODE, LAMBDA_DEFINITION_NODE, LIST_NODE, MODULE_NODE, MONAD_NODE, NILAD_NODE, OPEN_SLICE_NODE, PARENTHESIZED_NODE, PARSE_EXPRESSION_BLOCK_NODE, PARSE_STATEMENT_BLOCK_NODE, POLYAD_NODE, QDL_NULL_NODE, SELECT_NODE, SET_NODE, STEM_ENTRY_NODE, STEM_EXTRACTION_NODE, STEM_NODE, UNKNOWN_NODE, VARIABLE_NODE

Constructor Summary

Constructors
Constructor Description

Nilad(int operatorType)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Object`	`evaluate(State state)`
`int`	`getNodeType()`	QDL is not strongly typed but Java is, so each node type should have a unique integer and conditionals should use that, not the instanceof operator.
`ExpressionNode`	`makeCopy()`

Methods inherited from class edu.uiuc.ncsa.qdl.expressions.ExpressionImpl
evalArg, evalLastArg, evaluatedArgs, getAlias, getArgAt, getArgCount, getArguments, getEvaluatedArgs, getLastArg, getOperatorType, getResult, getResultType, getSourceCode, getTokenPosition, hasAlias, hasEvaluatedArgs, hasTokenPosition, isEvaluated, isSizeQuery, setAlias, setArguments, setEvaluated, setEvaluatedArgs, setOperatorType, setResult, setResultType, setSizeQuery, setSourceCode, setTokenPosition, toString

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Nilad
```
public Nilad(int operatorType)
```
- Method Detail
  - evaluate
```
public Object evaluate(State state)
```
  - makeCopy
```
public ExpressionNode makeCopy()
```
  - getNodeType
```
public int getNodeType()
```
    Description copied from interface: ExpressionInterface
    
    QDL is not strongly typed but Java is, so each node type should have a unique integer and conditionals should use that, not the instanceof operator. This allows for efficient programming with switch statements rather than a bevy of conditionals (potentially each of which gets done even if the correct case has been handled).
    
    Returns: