Package weka.core.expressionlanguage.common

Class IfElseMacro

java.lang.Object
weka.core.expressionlanguage.common.IfElseMacro
All Implemented Interfaces:
Macro, MacroDeclarations
public class IfElseMacro extends Object implements MacroDeclarations, Macro
A macro declaration exposing the ifelse function.

The ifelse macro can be used as follows:
ifelse(condition, ifpart, elsepart)

Whith the following constraints:
  • condition must be of boolean type
  • ifpart and elsepart must be of the same type
  • ifpart must be either of boolean, double or string type
Examples:
  • ifelse(A < B, true, A = B)
  • ifelse(A = B, 4.0^2, 1/5)
  • ifelse(A > B, 'bigger', 'smaller')
Version:
$Revision: 1000 $
Author:
Benjamin Weber ( benweber at student dot ethz dot ch )

  • Constructor Details

    • IfElseMacro

      public IfElseMacro()

  • Method Details

    • hasMacro

      public boolean hasMacro(String name)
      Whether the macro is declared
      Specified by:
      hasMacro in interface MacroDeclarations
      Parameters:
      name - name of the macro
      Returns:
      whether the macro is declared

    • getMacro

      public Macro getMacro(String name)
      Tries to fetch the macro

      The same invariant of MacroDeclarations applies here too.
      Specified by:
      getMacro in interface MacroDeclarations
      Parameters:
      name - name of the macro
      Returns:
      a macro

    • evaluate

      public Node evaluate(Node... params) throws SemanticException
      Evaluates the ifelse macro
      Specified by:
      evaluate in interface Macro
      Parameters:
      params - the parameters
      Returns:
      an AST (abstract syntax tree) node evaluating the ifelse function
      Throws:
      SemanticException