lispmultiuserfunction.java

计算机代数系统

package net.sf.yacas;


import java.util.*;

/// Set of LispArityUserFunction's.
/// By using this class, you can associate multiple functions (with
/// different arities) to one name. A specific LispArityUserFunction
/// can be selected by providing its name. Additionally, the name of
/// the file in which the function is defined, can be specified.

class LispMultiUserFunction 
{
    /// Constructor.
    public LispMultiUserFunction()
    {
      iFileToOpen = null; 
    }
  
    /// Return user function with given arity.
    public LispUserFunction UserFunc(int aArity) throws Exception
    {
      int i;
      //Find function body with the right arity
      int nrc=iFunctions.size();
      for (i=0;i<nrc;i++)
      {
        LispError.LISPASSERT(iFunctions.get(i) != null);
        if (((LispArityUserFunction)iFunctions.get(i)).IsArity(aArity))
        {
          return (LispArityUserFunction)iFunctions.get(i);
        }
      }

      // if function not found, just unaccept!
      // User-defined function not found! Returning null
      return null;
    }

    /// Specify that some argument should be held.
    public void HoldArgument(String aVariable) throws Exception
    {
      int i;
      for (i=0;i<iFunctions.size();i++)
      {
        LispError.LISPASSERT(iFunctions.get(i) != null);
        ((LispArityUserFunction)iFunctions.get(i)).HoldArgument(aVariable);
      }
    }

    /// Add another LispArityUserFunction to #iFunctions.
    public  void DefineRuleBase(LispArityUserFunction aNewFunction) throws Exception
    {
      int i;
      //Find function body with the right arity
      int nrc=iFunctions.size();
      for (i=0;i<nrc;i++)
      {
          LispError.LISPASSERT(((LispArityUserFunction)iFunctions.get(i)) != null);
          LispError.LISPASSERT(aNewFunction != null);
          LispError.Check(!((LispArityUserFunction)iFunctions.get(i)).IsArity(aNewFunction.Arity()),LispError.KLispErrArityAlreadyDefined);
          LispError.Check(!aNewFunction.IsArity(((LispArityUserFunction)iFunctions.get(i)).Arity()),LispError.KLispErrArityAlreadyDefined);
      }
      iFunctions.add(aNewFunction);
    }

    /// Delete tuser function with given arity.
    public  void DeleteBase(int aArity) throws Exception
    {
      int i;
      //Find function body with the right arity
      int nrc=iFunctions.size();
      for (i=0;i<nrc;i++)
      {
        LispError.LISPASSERT(((LispArityUserFunction)iFunctions.get(i)) != null);
        if (((LispArityUserFunction)iFunctions.get(i)).IsArity(aArity))
        {
          iFunctions.remove(i);
          return;
        }
      }
    }


    /// Set of LispArityUserFunction's provided by this LispMultiUserFunction.
    ArrayList iFunctions = new ArrayList();//<LispArityUserFunction*>

    /// File to read for the definition of this function.
    LispDefFile iFileToOpen;
};