Javascript Indirect field reference

ronpyatt

I hope I'm asking this question correctly...
Is there/ will there be a function that might allow me to access a field value by reference instead of having to use its name directly?

For example, I have 25 skills, which I represent each skill with its name, rank and modifiers. Fields: Skill1, Rank1, Mod1; Skill2, Rank2, Mod2, ..., Skill25, Rank25, Mod25.

I've been accessing each field as it is named (typed out in the code), which can get very extensive. It would be nice if there was a way to access those field values by reference using a string such as Field('Skill' + varx).Value, Field('Rank' + varx).Value, Field('Mod' + varx).Value.

Ed_NBOS

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.

royb

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.

Glorfindel69

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);
}