Is it possible to implement a method that returns the custom variables from the input given by the user?

[KenobySky]

Hi! This library is great. Im having just one requirement, however:

Is it possible to implement a method that returns the custom variables from the input given by the user?

For example, the user inputs:

String input = "(workHours^2 * workers)/100";

And for that given input, the method would return : "workHours", "workers".

---

I did a method that attempts to do that, it works fine except when the variable name contains a number. For example: String input = "workHours1^2 * workers2) / 100";

....
allBrackets = new HashSet<>();
        allBrackets.add("(");
        allBrackets.add(")");
        allBrackets.add("[");
        allBrackets.add("]");
        allBrackets.add("}");
        allBrackets.add("{");

        allOperators = new HashSet<>();
        allOperators.add(LocalizedEvaluator.MULTIPLY.getSymbol());
        allOperators.add(LocalizedEvaluator.MODULO.getSymbol());
        allOperators.add(LocalizedEvaluator.DIVIDE.getSymbol());
        allOperators.add(LocalizedEvaluator.EXPONENT.getSymbol());
        allOperators.add(LocalizedEvaluator.MINUS.getSymbol());
        allOperators.add(LocalizedEvaluator.NEGATE.getSymbol());
        allOperators.add(LocalizedEvaluator.NEGATE_HIGH.getSymbol());
        allOperators.add(LocalizedEvaluator.PLUS.getSymbol());

        allFunctions = new HashMap<>();
        allFunctions.put(LocalizedEvaluator.RAIZ, LocalizedEvaluator.RAIZ.getName());
        allFunctions.put(LocalizedEvaluator.ABS, LocalizedEvaluator.ABS.getName());
        allFunctions.put(LocalizedEvaluator.ACOSINE, LocalizedEvaluator.ACOSINE.getName());
        allFunctions.put(LocalizedEvaluator.ASINE, LocalizedEvaluator.ASINE.getName());
        allFunctions.put(LocalizedEvaluator.ATAN, LocalizedEvaluator.ATAN.getName());
        allFunctions.put(LocalizedEvaluator.AVERAGE, LocalizedEvaluator.AVERAGE.getName());
        allFunctions.put(LocalizedEvaluator.CEIL, LocalizedEvaluator.CEIL.getName());
        allFunctions.put(LocalizedEvaluator.COSINE, LocalizedEvaluator.COSINE.getName());
        allFunctions.put(LocalizedEvaluator.COSINEH, LocalizedEvaluator.COSINEH.getName());
        allFunctions.put(LocalizedEvaluator.FLOOR, LocalizedEvaluator.FLOOR.getName());
        allFunctions.put(LocalizedEvaluator.LN, LocalizedEvaluator.LN.getName());
        allFunctions.put(LocalizedEvaluator.LOG, LocalizedEvaluator.LOG.getName());
        allFunctions.put(LocalizedEvaluator.MAX, LocalizedEvaluator.MAX.getName());
        allFunctions.put(LocalizedEvaluator.MIN, LocalizedEvaluator.MIN.getName());
        allFunctions.put(LocalizedEvaluator.TANGENTH, LocalizedEvaluator.TANGENTH.getName());
        allFunctions.put(LocalizedEvaluator.TANGENT, LocalizedEvaluator.TANGENT.getName());
        allFunctions.put(LocalizedEvaluator.SUM, LocalizedEvaluator.SUM.getName());
        allFunctions.put(LocalizedEvaluator.SINEH, LocalizedEvaluator.SINEH.getName());
        allFunctions.put(LocalizedEvaluator.SINE, LocalizedEvaluator.SINE.getName());
        allFunctions.put(LocalizedEvaluator.ROUND, LocalizedEvaluator.ROUND.getName());
        allFunctions.put(LocalizedEvaluator.RANDOM, LocalizedEvaluator.RANDOM.getName());

....


public static ArrayList<String> getVariables(String input) {

        for (String operator : allOperators) {
            input = input.replace(operator.trim(), "");
        }

        for (Map.Entry<Function, String> entry : allFunctions.entrySet()) {
            String translated = entry.getValue();
            input = myReplace(input, translated, "");
        }

        for (String bracket : allBrackets) {
            input = input.replace(bracket.trim(), "");
        }

        input = input.trim();

        String[] words = input.split("\\s+");
        
        ArrayList<String> result = new ArrayList<>();

        for (String word : words) {
            word = word.trim();
            if (!isNumeric(word)) {
                //
                word = word.replaceAll("\\d", "");

                //
                result.add(word);
            }
        }
        
        return result;

    }

[fathzer]

Hi, I'm not sure to exactly understand your question, but maybe what you need is just to override the AbstractEvaluator.evaluate(Constant ,Object) method of your evaluator.

Here is an example based on DoubleEvaluator:

import java.util.*;
import com.fathzer.soft.javaluator.*;

public class Test {
	private static class MyEvaluator extends DoubleEvaluator {
		private static final Parameters PARAMS;
		private static final Map<String, Double> MY_CONSTANTS;
		
		static {
			MY_CONSTANTS = new HashMap<>();
			MY_CONSTANTS.put("workHours", 2.0);
			MY_CONSTANTS.put("workHours1", 1.0);
			MY_CONSTANTS.put("workers", 10.0);
			PARAMS = DoubleEvaluator.getDefaultParameters();
			for (String constant : MY_CONSTANTS.keySet()) {
				PARAMS.add(new Constant(constant));
			}
		}
		
		protected MyEvaluator() {
			super(PARAMS);
		}
		
		@Override
		protected Double evaluate(Constant constant, Object evaluationContext) {
			Double result = MY_CONSTANTS.get(constant.getName());
			if (result==null) {
				result = super.evaluate(constant, evaluationContext);
			}
			if (evaluationContext instanceof Set) {
				((Set<String>) evaluationContext).add(constant.getName());
			}
			return result;
		}
		
	}
	
	public static void main(String[] args) {
		final MyEvaluator myEval = new MyEvaluator();
		test(myEval, "(workHours^2 * workers)/100");
		test(myEval, "(workHours1^2 * workers)/100");
	}
	
	private static void test(MyEvaluator myEval, String expression) {
		final Set<String> used = new HashSet<>();
		final Double result = myEval.evaluate(expression, used);
		System.out.println(expression + "="+result+" with use of "+used);
	}
}

It gives the following output:

(workHours^2 * workers)/100=0.4 with use of [workHours, workers]
(workHours1^2 * workers)/100=0.1 with use of [workHours1, workers]

Hope this could help.
Best regards,