Javascript Indirect field reference

Comments

• Ed_NBOS

  November 2010

  No, I dont think there's a way to do that. I can look at adding such, but it woundnt be for the 1.x version as I dont want to introduce incompatibilities.
• rroyb

  January 2011

  I also had an issue with this and found a solution (though kinda ugly) to deal with it.
  
  you can do something like this.

  for(i=1;i<=25;i++)
  {
      skillstr = eval('Skill' + i);
      rankstr = eval('Rank' + i);
      modstr = eval('Mod' + i);
  
      skillstr.Text = somevalue;  if i = 1 this will reference  Skill1.Text and so on.
      rankstr.Text = some other value;
      modstr.Text = yet another value;
  }
  

  
  The trick is using the eval() function. Its not really considered a good thing to do, but it is the only way I have found to do what you want.
• GGlorfindel69

  March 2013

  Thank you royb!
  Your snippet helped me writing a script function that can evaluate a dynamic formula.
  
  Example.
  Say you have DataStore with named Skills

  Skill,Attribute
  Sneak,Dexterity+Quickness
  Melee Weapons,Strength+Quickness
  

  Add field Dexterity
  Add field Quickness
  Add field Strength
  Add field Skill1 with List property := Skills This will make it a drop down box with all items in the datastore
  Add field SkillFormula1 with Field Source := Lookup( 'Skills', Skill1.Text, 'Attribute') This will display the formula for selected item
  Add field FormulaResult1 with Field Source := CalculateSkillPotential(SkillFormula1.Text) This will calculate the value of the formula using fields in the sheet
  Some extra field for user information, txtOut and txtError
  

  // ******************************************************************************
  // Routine:       CalculateSkillPotential
  // Description:   Calculates skill potential
  // Parameters:    Attributes formula
  // Returns:       Potential as Number
  // ==============================================================================
  // Date       Version  Author                         Description
  // ---------- -------- ------------------------------ ---------------------------
  // 2013-03-21 1.0.0    Anders Forslund                Routine created
  // ******************************************************************************
  function CalculateSkillPotential(strAttributes)
  {
      // some debug related text fields
      txtOut.Text="";
      txtError.Text="";
      // setup default variables
      var dblPotential=0;
      var dblAttribute=0;
      // check that string entered is not empty
      if (strAttributes.length > 0)
      {
          // prepare string
          // split  into array
          var n=strAttributes.split("+");
          // loop array
          for (var i in n){
              // get attribute name
              strAttribute = n[i] ;
              // get value for attribute
              // enter error checking part
              try
              {
                  // check that valid number is entered in the text
                  if (isNumber(eval(strAttribute + "\.Text")))
                  {
                      // get value
                      dblAttribute = eval(strAttribute + "\.Value");
                      // sum potential
                      dblPotential = dblPotential + dblAttribute;
                  }
                  else
                  {
                      // invalid character in field
                      txtOut.Text= "Invalid number in field " + strAttribute;
                      return "E!";
                  }
              }
              catch (e)
              {
                  // something went wrong evaluating the attribute, inform user
                  txtError.Text= "Error evaluating attribute " + strAttribute + ": " + e.message;
                  return "";
              }
              finally
              {
                  // do nothing
              }
      }
      // completed ok
      return (dblPotential);
      }
      else
      {
      return "";
      }
  }
  

  Comments on the code above.
  Using dots(.) in string functions is tricky since the dot is a special character in javascript. That is why the escape character "\" is used in conjunction with the dot(\.)
  
  Support function

  // ******************************************************************************
  // Routine:       isNumber
  // Description:   Evaluates expression to check if it is numeric
  // Parameters:    Expression
  // Returns:       True/false
  // ==============================================================================
  // Date       Version  Author                         Description
  // ---------- -------- ------------------------------ ---------------------------
  // 2013-03-21 1.0.0    Anders Forslund                Routine created
  // ******************************************************************************
  function isNumber(n)
  {
    return !isNaN(parseFloat(n)) && isFinite(n);
  }