Java formulas in xml format

[Vassili Vladimir]

Hello,

I have mathematical formulas which will be used inside java code.

Is there a way or an API to express these formulas through XML and read it from code and execute it?

The reason for this is the formulas may change at any time.

Regards,

[Karthik Shiraly]

Here's one possible approach, using Java6 and its embedded Javascript script engine, to handle fairly complex math expressions without much DIY:

public class ExpressionEval {
	public static void main(String[] args) {

		String formulaFromDataFile = "userinput + 2 - 3 * 8 / 9 * sin(1.57)"; // Simulated read from text/XML file
		
		int userInput = 2; // Simulated value. Actually got from some user actions
		
		ScriptEngineManager mgr = new ScriptEngineManager();
		ScriptEngine jsEngine = mgr.getEngineByName("javascript");
		ScriptContext ctx = jsEngine.getContext();
		ctx.setAttribute("userinput", userInput, ScriptContext.ENGINE_SCOPE);
		
		String jsExpr = formulaFromDataFile.replaceAll("sin", "Math.sin"); // And other such javascript relevant replacements
		
		Object ret = null;
		try {
			ret = jsEngine.eval(jsExpr);
			System.out.println(ret.toString());
		} catch (ScriptException e) {
			e.printStackTrace();
		}
		
	}
}

[Paul Clapham]

MathML is a standard way to represent mathematical formulas in XML.

[Jesper de Jong]

As far as I know, the purpose of MathML is more to specify mathematical formulas so that they can be rendered in mathematical form. It's not really meant to specify formulas so that you can fill in values and "execute" (calculate) the result of the formula.