Package com.singularsys.jep.misc

Class MacroFunction

java.lang.Object
com.singularsys.jep.functions.PostfixMathCommand
com.singularsys.jep.misc.MacroFunction
All Implemented Interfaces:
JepComponent, PostfixMathCommandI, Serializable
public class MacroFunction extends PostfixMathCommand implements JepComponent
A function specified by a string. For example 
 MacroFunction fact = new MacroFunction(
            "fact",new String[]{"x"}, 
            "if(x>1,x*fact(x-1),1)");
 jep.addFunction("fact",fact);
 fact.init(jep);
 Node n = jep.parse("fact(5)");
Author:
R Morris.
See Also:

  • Field Details

    • varNames

      protected final String[] varNames

    • expression

      protected final String expression

    • preCompiled

      protected final Node preCompiled

    • topNode

      protected transient Node topNode

    • ev

      protected transient Evaluator ev

    • vars

      protected transient Variable[] vars

    • sv

      protected transient SubstitutionVisitor sv

    • jep

      protected transient Jep jep

    • nf

      protected transient NodeFactory nf

  • Constructor Details

    • MacroFunction

      public MacroFunction(Jep jep, String funName, String[] parameters, String expression)
      Create a macro function with two or more arguments defined by an expression.
      Parameters:
      jep - The jep instance
      funName - name of the function
      parameters - an array of the formal parameter names used by the function
      expression -
      Since:
      3.4.0

    • MacroFunction

      public MacroFunction(Jep jep, String funName, String parameter, String expression)
      Create a macro function with a single arguments defined by an expression.
      Parameters:
      jep - The jep instance
      funName - name of the function
      parameter - the name of the formal parameter.
      expression -
      Since:
      3.4.0

    • MacroFunction

      public MacroFunction(String funName, String[] parameters, String expression)
      Create a macro function with two or more arguments defined by an expression. Use this method for recursive functions like factorial. The init(Jep) method must be called after the function is added to the function table, which will recompile the function.
      Parameters:
      funName - name of the function
      parameters - an array of the formal parameter names used by the function
      expression -

    • MacroFunction

      public MacroFunction(String funName, String[] parameters, String expression, Node root)
      Create a MacroFunction from a node tree. The init(Jep) method must be called to compile the expression.
      Parameters:
      funName - function name
      parameters - list of parameters
      expression - string representation of equation
      root - root of expressions tree.
      Since:
      Jep 4.0

  • Method Details

    • init

      public void init(Jep j)
      The init method must be called after construction. This complies the equation, either by parsing the expression, or by copying the node tree specified in the MacroFunction(String, String[], String, Node) constructor. Names of variables are changed to be of the form name::varname, or as specified by the misc.MacroFunction.variableNameFormat message.
      Specified by:
      init in interface JepComponent
      Parameters:
      j - Jep instance
      Throws:
      JepRuntimeException - if errors compiling the expression.

    • setName

      public void setName(String newName)
      Change the name of a MacroFunction. Names of all variables are also changed.
      Specified by:
      setName in interface PostfixMathCommandI
      Overrides:
      setName in class PostfixMathCommand
      Parameters:
      newName - the function name

    • run

      public void run(Stack<Object> stack) throws EvaluationException
      Calculates the value of the expression.
      Specified by:
      run in interface PostfixMathCommandI
      Overrides:
      run in class PostfixMathCommand
      Parameters:
      stack - arguments for function
      Throws:
      EvaluationException - if the calculation cannot be performed

    • getTopNode

      public Node getTopNode()
      The actual expression used for evaluation, after substitution of variable names.
      Returns:
      top node of expression

    • getParameterNames

      public String[] getParameterNames()
      The names specified in the constructor.
      Returns:
      an array of names.

    • getVars

      public Variable[] getVars()
      Get the internal variables used, these have specific names like 'fun::x'
      Returns:
      list of variables

    • toString

      public String toString()
      Description copied from class: PostfixMathCommand
      Return a string representation of the function. If the name is not null, return the name, otherwise return the class name.
      Overrides:
      toString in class PostfixMathCommand

    • getLightWeightInstance

      public JepComponent getLightWeightInstance()
      Returns a new copy of the function, uses the MacroFunction(String, String[], String, Node) constructor.
      Specified by:
      getLightWeightInstance in interface JepComponent
      Returns:
      either a new instance, null or 'this'.

    • getDescription

      public String getDescription()
      Description copied from class: PostfixMathCommand
      Return a description of the function from the properties file. The property name is the class name followed by ".description". The property is found using the JepMessages class, which can be configured to add additional properties files. If PostfixMathCommand.setDescription(String) has been called, return the description set by that method instead.
      Specified by:
      getDescription in interface PostfixMathCommandI
      Overrides:
      getDescription in class PostfixMathCommand
      Returns:
      the description of the function